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'''Friday''' - We spoke about designing entire ecosystems, if it's possible and has anyone done it before successfully? we thought about designing ecosystems that include our mythological bacteria. In our case for our Samdura Manthan Bacteria I felt that it would work well as a weapon. So if we used in in darts and bullets they could be really lethal!!!!!
We found out that due to a political situation in the City we would have to leave early, so we split research work on the various actors we'd included in our giant mind map with which we will design a comic story on Moday! My task was to investigate America, Obama, the CIA etc and all their connections with Synthetic Biology.
We found out that due to a political situation in the City we would have to leave early, so we split research work on the various actors we'd included in our giant mind map with which we will design a comic story on Monday! My task was to investigate America, Obama, the CIA etc and all their connections with Synthetic Biology.
'''Saturday''' - Farhad, Aaron and I extracted my DNA. We were supposed to use the Hand Held Centrifuge, but the Centrifuge's Twist and Lock contraption seems to have melted beacuse of the heat created by the extra friction caused by the weight that it wasn't meant to take. We will send the blender back to the company to have the Locking system fixed. Only then can we see if our centrifuge works on actual DNA.
To read special entries click here > The Specials
Honestly all I knew about this competition was that it had something to do with biology and it was the memory of how much I used to love biology back in the tenth grade that motivated me to take it up. Also, there's a bit of a science fiction fan inside me!
We started work today. The majority of us being purely Art students came with the little knowledge that high school biology provides. We learned that we have missed out on a lot of details and that there is a sea of information out there that we need to know in order to fully and effectively exercise our creative skills.
Although I love biology I realised that I remember very little of what I had been taught, so I asked myself, how much do I remember? Though it seemed like a lot, the group discussion made me realise that it was hardly anything; most of what I remembered was either jumbled up with something else or was too vague and flimsy, and there was also quiet a lot of stuff that came out of no where...spontaneous generation? ha!...figments of my imagination!
We spoke about each of our perceptions on biology, a system, cells, DNA, genes and proteins, genetic splicing and what genetic engineering is all about. The theories on the origin of life and from where or how living cells came into existence, especially with so much diversity was another thing we discussed. Every theory makes sense in its own way, even with Pasteur's simple experiment to disprove the theory of spontaneous generation, no one can explain how the first cells, if there is a first that is, came into existence. As Karthik pointed out our brains are practically hardwired with the theory of cause and reaction, it is only natural that we assume that everything has an origin, things can't just pop out of nowhere. I personally believe that we don't know enough to disregard or discard seemingly irrational theories. Anything is possible.
The bbc documentary on cells gave us substantial insight into the history of the discovery of the cell and about the invention of the microscope; about Antonie van Leeuwenhoek and the other pioneers who planted major landmarks in the world of science.
We were also constantly trying to make sense of how we can contribute our skills as artists and designers to this world. When we started to learn about what genetic engineers did and about gene splicing and gene sequencing, it made sense, it's all an art; a gene sequence is like a colour, mixing different sequences would produce different results, i.e. different colours, the way you compose them on a canvas is the art. Once you get a hang of how to make the different colours, you can compose it anyway you like.
I got my kiddie microscope to class today, it isn't too bad, magnifies up to 600x. We placed a droplet of muddy water on the slide and we were able to see what looked like little translucent worms, but we weren't sure if it was just the dust and scratches on the lens or if it was in the water. Then we tried placing a thin piece of sliced leaf and saw the pores on its surface. We tried making a microscope using an old Logitech webcam, it was interesting to know that all we had to do after dismantling the webcam was invert the lens! This made me realise that there's a lot of old stuff in all our homes which we could play around with and create new things; recycle and rebuild for some other purposes.
Then we watched videos on the Mendelian theory, how he observed and theorised the process of genetic inheritance using the pea plants, we were given examples of how this works in human beings. We learned about genomes, chromosomes and genes, a chromosome is sort of like a complex pack of genes. A gene in itself contains strands of DNA, which in turn contain pairs of bases-ATs and CGs.
For me, the coolest part was that Mendel was a monk and Antonie van Leeuwenhoek was an apprentice to a cloth merchant; and both of them are now seen as the forefathers of today's Science. Growing up in a time when the Arts and the Sciences were perceived as immiscible (for the most part), it was empowering and reassuring to learn that just about anyone could be the next person to go down in history for discovering or coming up with an idea that could prove to be invaluable to the world.
Apart from watching more videos about genetics, our task today was to create an imaginary creature. It could be absolutely useless and whimsical. These kinds of assignments are my personal favourite!
I've thought about this many times (although not in this context).Ever since I was little I remember imagining creatures; watching cartoons and TV shows with things that you wouldn't really see living on your planet makes you wonder and makes you dream about your own little (or really huge) creatures. Recently while watching Avatar I was constantly imagining things and I was really excited to do this exercise.
So my creature would be something that floats or flies. I wanted it to be translucent with a slight portion of its insides visible to us on the outside, I wanted it to be roughly the size of a medium sized bubble or a tennis ball. I wanted it to be a wobbly sphere.
Now, I didn't want my creature to be completely useless, since we are in great need of air purifiers, especially in big cities like Bangalore, why not create something that fed on the pollutants. Every time the pollution increased in the atmosphere these little creatures start sprouting out. It's their source of nutrition. I decided to name it Purgcaelum. It's latin for purify air (purg and caelum respectively).
I found that Nitrogen oxides are major pollutants, so I wanted Purgcaelum to be able to turn the nitrogen oxides into ammonia that could be helpful to plants. I wanted it to perform the role of nitrogen fixing bacteria! I'm not sure about how scientifically possible this task is though...
We're also doing a living art piece. Using any medium of portrayal, we're going to take a living thing and study it's pattern of growth or behaviour. As against cruelty towards living things as I am, I decided to study fireflies to see how I could control their behaviour (I will let them free ofcourse). Finding them around where I live however, is very difficult. I'm not even sure if it's their habitat.
After a lot of research, I found that sadly fireflies all around the world are endangered. Well, seeing a firefly in itself was a huge deal for me as a kid, forget catching one. I haven't seen one in years. It's extrememly sad. We should save them.
Our previous ideas for creatures while crazy weren't crazy enough, so we set out to intensify their crazy quotient.
I thought up a whole new idea. And this is most definitely not possible, atleast won't be (I think) for many many years. And it is that, my creature is able to carry out the process of nuclear fission with in its body. It has a lining of concrete to protect its out membranes from exposure to the radiation and for it to coexist peacefully with the other organisms. Now why it needs this process is to create enough energy to produce enough pressure to survive both in shallow waters and in the deepest parts of the ocean. It has a highly developed pressure sensor.
Very little of the earth's seabed/ oceanbed has been explored by mankind due to the high amounts of pressure and this creature would be just the thing we need to look into the unexplored. It also has photogrpahic memory which we can easily access since its brain can be hacked into by humans. Again it is sphereical in shape with many pressure nodules on it's surface, it has eyes, a mouth and breathes as well. The nodules also act as the pressure sensors.
A colony of these creatures can be used to harvest energy to power whole cities.
Just got back to college today after four days of being ill, I missed out on the DNA extraction, but was explained the process of how it happens and how it looks. I never imagined it to be so simple, the very term 'DNA extraction' sounds like one needs an entire lab (like dexter's lab) to facilitate it!
This made me think on a more philosophical note; all the things that we think are really difficult, that are complicated and almost impossible to do are sometimes and most of the times the simplest and easiest to do, while the ones which we wrongly assume to be easy end up being really tough while doing them.
We FINALLY went to the National Centre for Biological Sciences (NCBS) today! This place is bea-uti-full!!!!! It's so fancy, shiny labs, awesome rooftop cafes, and a dinning hall with inexpensive yummy food (or so I heard). We were supposed to meet up with Mukund, but couldn't since he was busy but we did get to meet another scientist, Shorab(I not sure about the spelling...) who spoke to us about the experiment he was working at that moment(literally, he'd even timed himself and the alarm went off for him to go back while he was in the middle of our discussion). It was to do with mice brains and their brain activity, he said a lot of things about the synapse, which I cannot recall since a very little of it made sense...but it did sound very interesting.
However what caught me was that he had to kill the mice before he worked on slices of their brain. He said that they're anesthetised before they're killed so I don't think they feel pain; they are not employing cruel methods, so that's good.
We met another scientist, who showed us around the labs and told us what the different machines do. It was amusing to find out that half the machines in the lab were only used to mix ingredients!
Also, we had a very interesting conversation in the morning at NCBS, it was about how a scientific institue could afford to be so luxurious while a majority of our country was starving and shelterless. How does our government prioritize? Does it even prioritize? We came up with many explainations to this, but I wonder, are we in a position, as a 3rd party, as outsiders to both the groups in question, to make assumptions about the situations. I think we need to listen to both stories and the government's story, and only then can we make a fair judgement.
Finding fireflies is super hard! So while I'm still on the look out for them, I decided to try my music test on ants. I took two different kinds of ants. I'm not sure I can identify them because there are 632 different species of ants in India! All I can say is that on was a big black ant, with a longer body, while the other was smaller with a boxier body.
I put them in the glass bottle I'd saved for the fireflies with a two long leaves for company. The bigger one was more active on the whole, while the smaller one was mellow. I strated off playing really loud hip hop! It didn't seem to faze them much, the big one became more limited in it's exploration of the bottle while the smaller one hid under one of the leaves. It was very still through out. Next I gave them same quiet time. The big one resumed running around, the small one was still under the leaf. I started playing 3oh!3, then tweaked it by increasing the pitch (which was very very disturbing) and this time I played it on ear phones and I hung one ear phone into the bottle midway. Again they did the same thing, the little one was still under the leaf and the big one froze up on one of the leaves. I took the ear phone out and played it out loud, same reaction.
Now here's the interesting part, I played Explosions in the sky, who are a lot more soothing to human ears than 3oh!3 and the little guy actually came out from under the leaf, I don't know if it was just him getting used to the music but at one point it was as though he was coordinating his leg and antennae movement to the music. It probably was just coincidence or my imagination going wild but just to double check I'm going to repeat this experiment with different ants. Let's see what happens! However, I didn't see reaction as pronounced as I was hoping!
Moving on, hre's another idea. Instead of plastic, we could use bacteria. Bacteria which we could use in all the ways we use plastic, for bags, containers, clothes etc etc. The best part is that it's biodegradble! When the bacteria start dying we just put the product in a compost bin and use it as manure!
I had an inkling that there is already something like this out there, and yes there is, so take a look at this, it may not be exactly what I'm talking about but it's close enough to what I'm saying! http://www.scientificamerican.com/article.cfm?id=turning-bacteria-into-plastic-factories-replacing-fossil-fuels
We tried to grow yeast today! We went up to the Aditi Lab and made some agar. We then tried colonising three different forms of yeast on the agar plates. One plate was smeared with dry yeast mixed with room temperature water, one with yeast in warm water and another with just dry yeast. We will leave it undisturbed for two days and see what happens!
Today, we went for a talk and presentation on Darwin's theory of evolution by Dr. Narsimhan at the National Institute of Advanced Studies. It was mainly a discussion about how much chance and how much design is involved in the making of the world. The presentation definitely brought on some questions and confusion, which I will write about in detail soon (which I will post in my Special entries section).
Later that day we went to NCBS again, we met Mukund (finally!) and he showed us around the area where we will be working. He also suggested that we make our own lab equipment! So this should be really cool! :)
We started work on building our lab equipment. We did some research on how to build incubators and centrifuges. I always felt that we needed something super fancy to make things happen but this course has kept surprising me with how much we can do with stuff we have lying around at home!
We had a look at what had happened to the yeast on the agar plates (to see if there were any colonies) and only one had some kind of growth, the one sprinkled with dry yeast was the only one that showed some kind of development while the rest were not so successful.
We also tried a new formula for the agar plates, we changed the agar:water proportions to see which one gave the best results. I think the one with 5g of agar to 250ml of water worked the best, it wasn't too dry and hard nor was it too gooey.
7th - 12th June 2010
This week was mostly about constructing our lab equipment, with the centrifuge not cooperating with our attempts at trying to make it work, it was a little crazy and at times frustrating. We got a table top mixer, we tried connecting a pipe to it's blade which we were hoping would spin, but the pipe was almost impossible to keep stable on the blade without making it permanent, and since we weren't sure about whether the rest of the idea would work or not, we needed something temporary, so after a lot of trial and error, we figured that all we need was the axis on which the blade rotated, if we could fix a round disc or metal trips on the part where the blade goes it would prove to be a lot easier, and as it happens it was a lot easier. We also had to deal with strong vibration and we were able to do away with them as well. Once the sealant used for covering the bottoms of the test tube holders has dried completely we will try this out, it should work.
Simultaneously, we made a hand held centrifuge using a hand blender. This was relatively easier to make since we had learned how to dodge certain problems from the table top version. It's quiet effective on chalk powder and poster paint but we still haven't tried it on actual DNA. I hope it works, this one's sort of like my baby :D.
The incubator was stubborn too, we only got it to maintain a near steady 37 degrees C on saturday. We realised that the thermocole ice box didn't really need aluminium foil lining and a light bulb beacuse these made the temperature rise over 100 C, with the clinical thermometer bursting! We also figured that it needed an industrial thermometer and four fans instead of the initially estimated, one. With four fans and a mosquito repellor providing heat our team mates were able to notice an almost steady temp. of 37 degrees C which was exactly around what we were hoping to achieve. Now all we need to do is see if the mosquito repellor affects the specimens in the petri dishes, if it does, then we will have to find an alternate source of low heat. I was thinking maybe a few Christmas lights or the little blubs used in torches, I think they would provide enough heat and we we could just use batteries to power it; making it more portable.
Can't wait for Monday!:)
14th, 15th and 16th June 2010
Alexandra and James are here! We presented a slideshow of our progress until now and they showed us their work.
On the first day, we spoke about our ideas and categorised them under the categories made by the Design for the First World competition. From what I gathered from the discussions that we had, trying to "solve" a problem is such a western thought and while critiquing western design it wouldn't really help us to think in exactly the same way that has been there. And this does make sense.
On the second day, we were asked to look up a previous Igem teams' project and imagine that this idea was actually being put into effect sometime in the future. We chose Team ULB-Brussels' project Glucoli, a bacteria which secretes a biodegradable and natural adhesive. My initial idea behind proposing to use this team's project in context was that, this product could be used as an innovative way to kill people. Since our exercise was to report the repercussions of the product as a news report, I felt that this idea would make a good story to report. Later my team mates and I changed it up a little to make a new story. However, I think a little more organisation from our side would have been more justifiable to our portrayal of the situation.
On the third day, we were split into groups again, this time it was to actually take part in the competition we had designed the day before which is for bio-artists and designers. It's called IGEA, the International Genetically Engineered Art Competition.
Our team was supposed to make a piece of art that fit into the categories - a Social Critique and an example of the Remix culture. We came up with many ideas, one of mine was to question our idea of personal space and hygiene. We're always so fussy about personal space and hygiene, especially me, and I wondered what would happen if we knew just how many people had touched every single object around us before we touched it. Would we be disgusted? would we feel like perpetually living under a wash basin? Or would it make us feel more at home? Less lonely, more connected? While this idea was a social critique, we couldn't see how it could connect to Remix culture.
Anyway, we finally ended up questioning where genetic engineering will take us in the future? an evolutionary glass ceiling?
Here's my interpretation of how our group poster could look -
I don't know whom to credit the original(unmodified) picture to, I hope whoever it is doesn't mind and isn't offended that I modified it.
On Thursday, we had a presentation on telling stories. We watched clips of the movies The Man in the White Suit and Spirited Away (A Japanese anime....which was very interesting). We also looked at Polish film posters. Generally film posters aim at easy readability, and a sort of in your face message, but these posters were abstract, unless you knew what the movie was about you wouldn't know what the poster was trying to convey. So in a way I think this a clever strategy; you go watch the movie just to decipher the poster! Makes you wonder about how Polish people think....they must have a really interesting thought process!
We were also supposed to re-work on our presentations and present them on Friday. Our group decided to take up a new idea since all of us felt that the previous idea was too generic. Our final idea was to make bacteria which tell you what the weather is like by playing a certain music playlist. We called it E.Cloudy.
We went critical on this project. We looked at almost every aspect of what could go wrong with it and what could become popular. We listed it out and I think this really helped us sort out the project. In the end it worked out well, but we hoped to make a 3D model which we couldn't, but we will some time soon.
On Saturday, we read some stories from the Amar Chitrakata books about Shiva and the other Gods. I'm not an extreme feminist but some parts of the story set something off in my head and I just couldn't get around the fact that women were treated and perceived in the way that I perceived them in the stories. Maybe it's just me, but yeah this was sort of annoying. However I didn't know a lot of these stories so it definitely was good to read them. Anyway our idea behind reading these was to see what hybrids and genetic engineering we could find in our Hindu mythologies. One of the groups that presented had worked on how sages in history would go into a state of trance due to the internally produced DMT (which I think is really awesome! :D) and there were also talks about Shiva's third eye, and this led me to think about all the other Gods, like Hanuman, Brahma and Garuda, all of whom are very modern images of science fiction. It brings you to question how our ancestors imagined these things, what made them believe that these things were in existence and were possible, was there a time when such people (or Gods?) did exist?
The soma bacteria
This idea of the soma bacteria is primarily inspired by the popular Hindu myth of the samudra manthan , commonly known as "the churning of the ocean". The phrase "soma bacteria" comes from the drink of "soma", which is a drink primarily behaving as an anesthetic in the famous mythical incident of Samudra manthan.
Now we come to the working of the bacteria:
The soma bacteria are not just one bacterium but a pair of bacteria, which are co- dependent, and they are unstable in the absence of each other. One bacterium is harmful in relation to the human body, whereas the other one is harmless, but it is to be noted that it is not of a curative nature. The habitat of these bacteria is common rust. While they live in their rusty habitat, they live in colonies but there is no activity of exchange taking place. The minute it comes in contact with the human body, the bacteria get activated at once. It commutes throughout the human body, causing harm. The minute it comes in contact with a WBC, the two bacteria start exchanging their genetic material rapidly. While the WBC recognizes that one bacterium is harmless, it also realizes that the other one is harmful. But due to the rapid state of exchange of genetic material, the WBC is unable to recognize the harmful one and try and kill it. While the harmless bacterium contains a protein, which the WBC cannot counter, it cannot kill either of the bacteria. Thus, the WBC can never destroy the soma bacteria at any given time.
June 21st to 26th 2010
Monday - Daisy's Birthday!!!!! Happy Birthday! :D This day, we looked at how we could organise potential synth bio material we had collected from the myths we'd read. We looked at categorises such as Soma ( a durg like substance believed by some to be a drink of immortality and and by some as an anesthetic, a drink that keeps you happy), jugaad ( I finally know what this word means!!!), Karma and Immunisation against a Disaster, etc.
Later in the day, we tried to take the way the myths were told and use them in context of a synth bio scenario. Anusha, Diya and I teamed up to come up with something. Our initial idea sprang out of us questioning the role of Priests. We wanted to create a bacteria that specifically killed priests. We thought we could make bacteria which lived in Camphor, which in Inida we use to burn and use as little lamps in temples!
We also went over to Yashas' place to hear Arshia Satta talk about Shiva and clarify our doubts on the mythologies we'd been reading. Further thoughts on this will come up in my specials page! (Look at the begining of my page)
Tuesday - We started making our stories more scientific. We decided on bacteria which rapidly switched genetic material and dodged WBCs in the human body. They need to do this since one of the bacterium in the pair of the co-dependant bacteria is seen as harmful by the WBCs while the other one which produces histamine isn't seen as a foreign body. This bacteria lives on iron and feeds off the haemoglobin in the RBCs.
We made a poster for our bacteria.
Wednesday - we re-iterated our poster for our bacteria since it wasn't very vocal. This time I think it made more sense. This day we also made an enormous mind map which included everyone related to synthetic biology.
Thursday - We finished making our power point presentation on the Biobricks that would come into play to make the Samudra Manthan bacteria possible. We were supposed to present it to Mukund and seek scientific opinion but he had to cancel for some reason. We will hopefully present to him next week.
We also met the Level 10 Comics guys today and what was really nice about their work was that it was based in familiar spaces. Their stories about Bangalore (and an illustration which showed Mallya Hospital in ruins after a zombie attack) were brilliant, it was a different expirience than compared to stories about Cities in countries we've never been to, localising these stories we've been hearing and watching in cartoons and movies is another thing! It was fun! Next time I'm somewhere close to the Vidhan Sauda I can't help but start imagining half dead people and blood all over the place!!! And I think this is the only time when I'll be soo excited to see such mayhem in our city!!!!
We were also invited to a play by Aditi at Alliance Francaise that evening. It was called The Clearing. It was awesome! I loved it! It was a story weaved around a plant called lantana!
Friday - We spoke about designing entire ecosystems, if it's possible and has anyone done it before successfully? we thought about designing ecosystems that include our mythological bacteria. In our case for our Samdura Manthan Bacteria I felt that it would work well as a weapon. So if we used in in darts and bullets they could be really lethal!!!!!
Saturday - Farhad, Aaron and I extracted my DNA. We were supposed to use the Hand Held Centrifuge, but the Centrifuge's Twist and Lock contraption seems to have melted beacuse of the heat created by the extra friction caused by the weight that it wasn't meant to take. We will send the blender back to the company to have the Locking system fixed. Only then can we see if our centrifuge works on actual DNA.
Retrieved from "http://www.hackteria.org/wiki/index.php?title=Samrajni_Patil&oldid=2390"


Interest Rate Guarantees under ICS/Solvency II – Don't let your legacy book disturb you!
Dr. Günter Schwarz is a German and was born in 1959. He has studied mathematics and physics and received his PhD in 1989. In 1995 he was awarded with the title of a "Privatdozent (Dr. habil.)" by the University of Mannheim. In 2002 he nominated as a fellow of the German Actuarial Society.
Dr. Schwarz looks back to a long academic carrier in Germany and Canada. Since 1997 he works for the insurance industry, first as a mathematician with an actuarial consultant firm and since 2003 with Munich Re. He focus is on accounting and regulatory issues and leads a specialist team responsible for structuring reinsurance transactions both in order to achieve supervisory recognition and to optimize the anticipated effects on the client's balance sheet. During 2010-2013 the also headed the Global Life Solvency project and since 2018 an IFRS 17 project, both focus on developing Munich Re solution for Solvency II and consulting clients. Dr. Schwarz has been nominated as a member of several task forces in the German Actuarial Society (e.g. "Options and Guarantees" and "IFRS Accounting"). Since 2010 he also is appointed as a lecturer at the Ludwig Maximilian University Munich.


text:
Part 1: 2012 Henryville tornado confronted Hoosiers with life-and-death decisions
robert.king@indystar.com
This story was originally published on May 13, 2012.
Victor Arnold stepped out onto his back porch and gazed up at the sky over Fredericksburg.
At 56, Arnold had lived here in the heart of Southern Indiana for most of his life. But he'd never seen what the sky was doing right now: It was spinning.
Arnold lowered his gaze. That's when he saw it.
Bouncing back and forth across the treetops to the west was a curving sidewinder of a thing that resembled Dorothy's cyclone in "The Wizard of Oz."
It was a tornado. And it was roaring.
Arnold called inside to his mother, Virginia. Take cover, he told her. He helped her crawl under a computer table.
Maybe, he thought, they would need some protection against flying debris. So he went to the bedroom and grabbed some blankets.
He also grabbed the tomcat, which had been sleeping among them. Arnold went to the archway, pulled the cat and his two dogs next to him and covered them all with the blanket.
Then it hit.
49 Miles, 49 Minutes:
Part 2: School and bus in path of 2012 Henryville tornado
Part 3: 2012 Henryville tornado reshaped lives and landscape
The tornado's winds, already at 130 mph, peeled back the roof, toppled the chimney and lifted the house off the ground, moving it 3 feet to the north.
Under his blanket with the animals, Arnold was oblivious to the extent of what was happening to the home. He heard the windows shatter, but he didn't notice a jolt, no freight train noise. He even wondered whether the tornado had missed.
But as he pushed out from under the covers, Arnold felt things falling to the floor. They were small chunks of his roof. He looked up where the roof had been a few minutes before -- and there was blue sky.
It was no longer spinning.
The tornado had moved on. And it was just getting started.
From Fredericksburg, the tornado would wind its way to the Ohio River near Madison and briefly into Kentucky -- a journey of terror that would cover 49 miles in 49 minutes.
Both numbers are remarkable.
Tornadoes are one of the most unstable forces in nature. They typically are born and die within minutes, within a few miles of their birthplace. This tornado, which dropped from the sky at 2:50 p.m. on March 2, barreled across Southern Indiana for the better part of an hour.
Remarkable, too, were the mechanics of the storm.
The typical Indiana tornado lumbers along at 30 mph. This one swept across the state at 60.
It was fast -- and it was powerful. Many Indiana tornadoes produce winds no stronger than 100 mph. This one? Its swirling winds whipped up as strong as 175 mph.
On the Enhanced Fujita scale, which gauges a tornado's ferocity on a scale of one to five, this tornado at times rated an EF-4. In short, it was one of the most powerful tornadoes ever to hit the state.
Born from a weather system that packed two supercells as it moved through Indiana, the tornado traversed a region of the state that knows what powerful storms look like. Residents along its path remember Hurricane Ike in 2008, tornadoes from 2004 and the last monster tornado that struck, in 1974.
But most who encountered those storms say that what hit them on March 2 topped them all.
Some described what was about to upset their lives as if it were a living animal.
It roared like a beast, they said, and ate the objects in its path. To others, it seemed to stalk them like a predator or pursue them as they fled.
Images of the tornado, captured in photos and on video, show a storm that expanded and contracted, produced fangs and pointed fingers. At times, the tornado even sprouted sisters.
Some accounts of the tornado were deeply personal.
The tornado pulled at people's skin, made their ears pop and their noses bleed. More than one person said the tornado lifted them off the ground. One person described a storm chase in which the tornado seemed to be the one doing the chasing. It ended with a father clinging to his daughter at the threshold of safety, only to feel the tornado try to pull her away.
The tornado cut across three counties (Washington, Clark and Jefferson) and a sliver of a fourth (Scott).
Along the way, it demolished mobile homes, manufactured homes, log cabins and even brick McMansions.
It swept into a state forest, thick with trees, and mowed down everything in its path.
It laid waste to Marysville, casting doubt on whether that tiny community will ever recover.
It delivered a direct hit to Henryville, thrashing the high school.
And it killed 11 people.
What follows is an account of the storm, the first in a three-part series that retraces the tornado's path from its start in Fredericksburg to the Ohio River, where its graceful exit as a waterspout belied the destruction in its wake.
Along the way, you will meet the people who encountered the tornado -- people who, in a matter of minutes, had to make terrifying life-defining decisions. The results of those split-second choices were sometimes fortunate, sometimes heroic, sometimes tragic.
The National Weather Service started issuing warnings of potential calamity three days earlier. In some ways, it was as close as possible to a climatological sure thing.
Temperatures that week had topped out in the 70s. It was shirt-sleeve weather in late winter. But arriving late in the week, forecasters said, would be a strong low-pressure system that could send temperatures plunging into the 20s. Worse yet, the system would arrive with high-altitude winds ranging from 50 to 100 mph.
"It was," as Brian Schoettmer, a weather service meteorologist in Louisville, Ky., said, "a classic setup."
The potential for trouble was such that bands of storm chasers began parking themselves across Southern Indiana, from Evansville to Henryville and across the river in Louisville.
As the sun rose on March 2, weathercasters were predicting hail and devastation. At 11:30 a.m., the weather service issued an unusually stern warning that "tornado outbreaks were likely."
As soon as the storm system moved into the state, it had people's attention.
Victor Arnold was one of them.
He'd spent a good part of the day -- his 56th birthday -- responding to well-wishers on Facebook and keeping an eye on the weather. And by 2:45 p.m., he noticed that the sky had taken on a weird gloom.
He headed toward the back porch just as the tornado was being born a mile away in a cornfield, where it snapped some trees along a shallow creek. It quickly moved over a ridge and through a pasture.
It arrived at the Arnold home, built by Victor's grandfather in the 1950s, and seemed to set off an explosion. It opened up the roof and scattered the family's belongings across the countryside.
Yet Victor and Virginia Arnold, one under a blanket, the other under the computer table, emerged unhurt.
"We were just lucky," Victor said.
The tornado rushed up the street quickly, plowing headlong into a 164-foot-tall electric transmission tower. As part of a necklace that stretches across the land, the towers have underground supports and concrete footings embedded more than 30 feet deep. The tornado would uproot nearly half a dozen such towers. Here, in Fredericksburg, it hit the tower with 130-mph winds, grabbing its steel skeleton, twisting it like a metal coat hanger and tossing it aside.
It was from this point that storm chaser Bob Hartig caught the tornado pressing four miles across the countryside on a video now on YouTube. The footage shows a tornado diving and ascending from a roiling sky, spinning wispy strands, pulling back and intensifying into a tower of white muscle. That's what it looked like as it crossed Ind. 135 near Dutch Creek Road.
As it hit the highway, the tornado brought with it winds estimated at 150 mph. It used them like a pry bar under the road, lifting a chunk of the highway roughly the size of a backyard swimming pool.
The asphalt was 4 inches thick, packed and heavy. But the tornado took the road and hurled it skyward.
Seconds later, in a farmhouse on Old Palmyra Road a thousand feet away, Anne O'Connell began to hear them: a meteor shower of sorts, the thuds of a series of heavy objects hitting her house.
She heard them from her closet.
O'Connell, 57, had known all morning the weather was going to be dicey. But as she became immersed in her housework, she lost track of the weather.
It became too hard to ignore when the world outside her windows began turning black.
O'Connell went to the front door for a look. When she opened it just a couple of inches, her dog, Katie, pushed her way into the house and disappeared. Katie, a boxer mix, lived outside and almost never came in.
O'Connell opened the door a bit wider, and it became obvious why Katie sought shelter: Debris was flying everywhere.
There was a cellar door under a rug in the kitchen. But O'Connell knew she didn't have time to get there. Her best option was her bedroom closet.
She called to Katie, but the dog wouldn't come. O'Connell wasn't going to try to reason with her. She entered the closet and closed the door. For protection, the closet offered her only a low ceiling, some piles of junk and, of all things, a gun. She pulled some coats down on top of her and started praying.
Outside, the tornado was mowing down the forest across the road like so much grass. It bullied into a long row of catalpa trees that had lined the property for 70 years and snapped them like twigs. It pelted a weathered barn that had stood for a century with tree limbs and chunks of Ind. 135. Built in a bygone era, the barn hung together. But it began to move, ever so slightly, on its stone foundation.
To O'Connell, all these things came to her as a buffet of sound. She heard glass breaking. She heard the heavy objects hitting the house. All she could do was pray and wait and pray some more. A calm came over her.
She was resigned to whatever fate the storm held for her.
O'Connell listened to the storm's bluster for five minutes. After it seemed to die down, she exited without a scratch. Katie was unharmed, too.
O'Connell went to the kitchen. Had she opted for the root cellar, this would have been her path. It's good she didn't.
The dishes she'd left in the open dishwasher were shattered. Pieces of her roof -- shingles, insulation and other chunks -- lay scattered about. And in a couple of places were some dark rocks she couldn't quite place. One had come through a hole in the ceiling right above and was now sitting, perfectly balanced, on the divider in the sink. It was 4 inches thick, heavy and had no business falling from her ceiling.
It was a chunk of debris that had been uprooted moments earlier a quarter-mile away.
It was a piece of Ind. 135.
Five miles farther east, in New Pekin, Town Marshal Jeff Thomas had been scurrying about all afternoon, trying to coordinate with the local schools. The storms were expected to arrive just as the buses were to start rolling for home. School officials eventually decided: They'd hold the kids in school.
Thomas wanted to make it to a ridge south of town where he normally went to watch the storms that roll in from the southwest. But as he drove through town, he heard the excited voice of a firefighter on his radio.
Tornado near Big Springs Road.
Thomas looked over his shoulder in that direction. And there, spinning up in the air, was a funnel cloud.
Thomas turned on the siren in his patrol car and began to race through the streets to draw attention to the coming calamity.
At Saroyan Hardwoods, a big lumber supplier in town, worker Steve Martin was in his forklift, unloading wood from a semi. He was oblivious to the havoc heading his way.
Thomas rolled by in his patrol truck. For some reason, he was pointing feverishly toward a nearby ridge. Martin couldn't figure it out. But as he turned his forklift around, it became clear what the fuss was about: A tide of debris was coming over the hill.
Martin yelled at the semi's driver to take cover, then drove his forklift into one of the wood warehouses. The cab of his forklift was encased in glass -- not a great place to be in a tornado -- but it weighed perhaps 25,000 pounds. It wasn't going to fly. Martin crouched down on the floor of the forklift. The semi driver outside could only cuddle up next to the machine.
To Martin, it sounded as if cannons had begun to fire.
The tornado pulled apart the metal sheeting on the warehouse. It twisted into pretzels the heavy steel beams that had been the building's skeleton. It grabbed the 20-foot-high doors attached to the heating kilns, ripped them away and flung them a mile. The warehouse seemed to be coming down on top of him.
Martin, 57, had lost his wife to an infection in January. Now it looked as if he'd be joining her. But what he feared the most was losing his son. Jason Martin had pulled into the lumberyard just as the storm hit; he must have come to warn about the storm.
He tried to get out of his car but saw it was too late. He dived into the back seat. As he did, an enormous bundle of wood tumbled over onto the car. Its roof was crushed.
As the tornado enveloped his world, Steve Martin feared the worst.
All this drama played out right in front of Rhonda and Steve Burnett.
As they stood in front of their welding shop across the street, they saw the tornado top the ridge, come down into town and tear apart the lumberyard. Now, the debris -- including large pieces of flying steel -- was being hurled in their direction.
The Burnetts took their two employees inside their shop and into a windowless bathroom in the core of the building. Their shop had been built sturdily. They briefly had a fitness center on its second floor and had made sure the flooring there was stout enough to handle the heavy exercise equipment.
But outside, the tornado was doing some heavy lifting of its own. The Burnetts sold trailers that carry heavy logs out of forests, big steel-ribbed rigs, and the tornado was kicking them around like toys. It was shredding the building's metal skin. And it was beginning to lift the framework.
It was as if the tornado were breathing life into the building.
To Rhonda's ears, it sounded like a roar.
For Josh Pellman, one of her employees, it was the sensation of a lifetime.
As the tornado roared overhead, Pellman became frightened. He heard a humming, whooshing noise unlike anything he'd heard before.
It was new to him because the tornado's engine was roaring loud enough to be heard by someone who had lived his 28 years in complete silence.
Pellman is deaf.
A few hundred yards ahead, Gene Lewellyn occupied the only brick home in a patch of town surrounded by mobile homes. He thought everyone in the neighborhood understood they were welcome to share his basement during bad storms. But no one had come.
Except for his son Kendall, and his son's daughter.
Lewellyn, 62, had been watching television since his wife called from Salem earlier and told him to pay attention. But the looming giant black cloud was ahead of where the weathermen had said the storm should be.
When Kendall appeared, he didn't mince words.
"Dad," he said, "this is a bad one."
They went to the basement, where Gene covered his granddaughter with his own body.
Kendall stepped out into the backyard for one last look. He also pulled out his camera phone for 20 seconds of footage of a tornado about to descend on a town.
The view is chilling. The tornado is a menacing white funnel that's practically rippling with muscles. It's potent, and it's poised to wipe out anything in its path as it crests the ridge above New Pekin on its way toward the lumberyard and the welding shop.
The screen wobbled as Kendall headed to the basement. As he went down the steps, the video flickered out. His dad, meanwhile, took one last glimpse out a basement window.
The funnel cloud hit the bottom of the hill and mushroomed. It was getting bigger.
In a mobile home across the street, 32-year-old Jason Miller stepped out onto his little wooden porch and, without thinking, called out reflexively at what he saw.
"Tornado."
He heard a scream.
It was Moriah Brough, his next-door neighbor. She stood on the steps at the door of her own mobile home with Joe Babcock, the father of her three kids. But after screaming, she darted back inside their mobile home. Babcock followed.
Miller knew that neither mobile home offered much protection against a tornado that was nearly half a mile wide. But he was sure that his double-wide home, with its attached front and back porches, was better anchored. And he called to his neighbors.
"Get out of there! Get out of there! Get to my house!"
Brough, back outside with a child in her arms, said nothing but hurried toward Miller's home.
Babcock emerged with the couple's two other children. Miller went to Babcock and grabbed one of them, 15-month-old Angel. The two men followed Brough into Miller's place.
Inside, the only refuge they had was a narrow hallway. Everyone huddled on the floor and started to pray.
After getting the family settled, Miller took out his phone and headed to the door for a peek. When he opened it, the tornado was eating his garage. To him, it was a giant animal, a roaring beast.
Miller slammed the door shut and then dived on top of the Babcocks. Miller held Angel in his arms. And he joined the Babcocks in prayer.
The home shook. There was a loud boom. The windows blew out.
Miller felt the mobile home lift off the ground and turn.
He opened his eyes.
He was 50 feet off the ground.
And in the middle of a tornado.
At the lumberyard, Steve Martin climbed out of the forklift with frayed nerves but no injuries. His forklift had a cracked windshield but had served well as an anchor.
It also had sheltered the semi driver from harm, even though he could do nothing more than curl up next to the rig. Martin's son, who had driven up just as the tornado arrived, escaped the crushed car with some bruised ribs.
Next door to the lumberyard, the tornado had ripped open the roof of Martin's home and moved the entire house 15 feet askew from its foundation.
After his wife's death two months before, and the loss of his home and his workplace in the tornado, Steve Martin was ready for what his daughter called a "2012 do-over."
"We're just coping with it," he said, "day by day."
The Burnetts and their two employees, including Josh Pellman, emerged unharmed from the welding shop, which no longer resembled a building as much as it did a tattered heap.
Surviving, too, was Gene Lewellyn, who crawled out of his basement with his son Kendall and his granddaughter. They emerged without a scratch. But the brick house Gene built in the 1970s had been leveled.
The sight of the house, now nothing but a few partial walls and a debris pile, came as a shock. In the basement, they'd heard the turbinelike whir of the tornado, but none of the noise of a house being blown apart.
"Oh, my God."
It was all he could say.
The view of the neighborhood was no better. The tornado had rolled through the mobile homes like a bowling ball. Next door, the tornado picked up one trailer and blew it over another. Then it blew the second trailer back into the first.
Across the street, the mobile home that the Babcocks had left was pulverized.
But so, too, was Jason Miller's -- the mobile home to which they had fled.
Sheriff's deputies and firefighters, who had followed the storm track, were quick to the scene. They began to sift through the rubble, looking for survivors. But, initially, they found no one at Miller's place.
About 300 yards away, at the Worley Lumber Co., owner Rick Lanham stepped out into a tornado-ravaged world and came across a battered, broken and disoriented Jason Miller. He was wandering around behind Lanham's sawmill. Miller had several broken bones and a gash in his back, and his left arm was nearly severed. And he wasn't sure how he had ended up there.
Lanham brought over a sheriff's deputy to speak to Miller. He said he'd been huddling with five other people in his home. Rescue workers scrambled. They'd been looking for survivors. But they hadn't known that five people were missing. They renewed their search with fresh urgency, looking for the Babcocks.
They turned up soon enough.
Sgt. John Miller, a 22-year-old volunteer with the Pierce-Polk Volunteer Fire Department (and no relation to Jason), was among the first on the scene. In a field between the lumberyard and the mobile home lots, he and others started finding the bodies.
Moriah Brough, the 20-year-old mother of three, lay dead with two of her children, Jaydon Babcock, 2, and Kendall Babcock, 2 months, near her.
About 15 feet away lay Joe Babcock, who had gone that morning for his driver's license and was excited about the work he had been picking up from the sawmill. Sgt. Miller needed just one look to know that Babcock, 21, was dead.
But close to her father, maybe 10 feet away, lay 15-month-old Angel Babcock. Sgt. Miller feared the worst for her. But she was kicking her feet. Miller checked her pulse, found one, gently picked her up and took her to an ambulance.
Angel became known as the miracle baby who survived.
Foreign press correspondents came to tell her story. Some came with distorted notions of how far the tornado had carried her. One asked, in all sincerity, how many miles Angel had flown.
In reality, Angel had been blown a few hundred feet. But it was far enough. She suffered a serious brain injury. After holding on for two days, Angel Babcock died.
In its sprint across Washington County, from Fredericksburg to east of New Pekin, the tornado covered 18 miles and destroyed 45 homes. It damaged scores of others. It killed five people, all in Joe Babcock's young family.
And yet the tornado was just beginning. It would pillage its way across 31 more miles, leaving more destruction, more death in its wake.
But here in Washington County, the terror was over.
In the days that followed, an army of volunteers from as far away as New Mexico would descend upon the area to remove the trash and debris.
Donations would roll in from far and wide. So much so that people who had lost nearly everything were heartened by the generosity of strangers.
Some, such as Victor Arnold, who turned 56 on March 2, tried to find the humor in the destruction. The storm came to his home on what he now refers to as his "birthday blowout."
Others, though, are struggling on this side of the storm.
Steve Martin, who hid on the floor of his forklift, had trouble sleeping for weeks.
So did Josh Pellman, the deaf man who heard the tornado. Though Josh is a big, muscular former bodybuilder, his wife, Melissa, said he now realizes there are dangers such as tornadoes that can break into his silent world before he realizes it.
Sgt. John Miller, who found the Babcocks in the field where they died, sought help from two chaplains in trying to cope with what he had seen.
Jason Miller struggles with survivor's guilt: He brought the Babcocks into his home. They died. He lived. "I shouldn't have thought that my house was that much stronger," he said. Knowing that the Babcocks' home was erased from the Earth -- and that they almost certainly would have died there, too -- was little consolation.
"I don't believe that God creates a tornado and that God kills people," Miller said. "He allows things to happen. He had a reason for saving my life."
Such sentiments would be repeated often in the stories that would unfold over the next 31 miles. In places such as Hanover and Chelsea and Marysville and at the next stop along this tornado's path of destruction -- a town just 10 miles from New Pekin with a school that was directly in the path of the onslaught: Henryville.
Heart of Henryville healing after 2012 tornados
Call Star reporter Robert King at (317) 444-6089. Follow him on Twitter at @RbtKing.

redpajama_set_name: RedPajamaCommonCrawl


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text:
XY Stage
Project CNC Mill Is Not Square, And It Shows
After our most recent test cutting session, I wanted to prepare our scrap MDF stock for the next test by milling off everything earlier and leaving a flat surface. And like most tests, there was an unintended and interesting data point: The surface is not flat. Not only that, it was the worst "not flat" yet. Our first cutting session did not result in a flat bottom surface, either, but because there was so much tool chatter, it was hard to distinguish one contributing factor to another.
The second cutting session left us a very smooth bottom surface. Since we eliminated the majority of chatter in this session, we thought chatter was a contributing cause and life was good.
But with the third session's results in hand, we now know it wasn't quite that simple. The nasty tool chatter has been mitigated, but the bottom surface is poor. The ridges are consistent with a cutter tilted from vertical axis.
The square-ness of this machine was always a question mark, because it was only set up by eyeballing against a machinist's square. This is better than most drill presses, but barely counts as a starting point for a vertical mill. MDF is more forgiving than machining metal, so the fact we have three clearly different grades of surface finish means something changed drastically between runs. Well, "drastic" relative to CNC milling norms, where the thickness of a sheet of paper is a big deal. In normal everyday human experience it was pretty small, but still, what caused the change?
After some consideration, we realized we already knew the culprit: our bent Z-axis ball screw. As our cutter travels in the Z-axis, its tilt relative to the table would vary slightly. Since we've been using the same piece of scrap MDF, every test session cut slightly deeper than the last. When we are lucky as in the second project's bottom surface, we find a height where things are very close to square, and we get a smooth finish. Otherwise we see ridges left by our endmill as it cut across the surface while not quite vertical, pushed off axis by the bent screw.
Back when we realized the Z-axis ball screw was bent, we thought we'd use it until it proves to be a problem. We have now reached that point. Between the bent ball screw and loose Z-axis rollers, redoing the Z-axis (for the fifth time!) is moving up on the priority list. But not at the top yet, because even though we've identified this limitation, we still have things we can explore.
Running CNC Program Again Shows Encouraging Consistency
Once we made adjustments to Fusion 360 defaults to be friendlier to our scratch built CNC mill, the generated G-code program gave us better results with less tool chatter. There's still more chatter than we'd like, so we still need to find and fix weak points like our Z-axis rollers, but these CAM parameter changes are enough to let us continue exploring the world of CNC in parallel with our mechanical work.
This test program was generated by Fusion 360's "2D Adaptive Clearing" feature. The tooltip for the feature explained its intent is to minimize abrupt changes in direction, which we think is a good thing for a machine lacking rigidity. What it also means is an impressive looking tool path far more complex than what we would try to write by hand.
After we ran this program on our scrap MDF test piece (already partially cut from earlier tests) we vacuumed away the debris and saw a very satisfying result. The rough edges from tool chatter have all but disappeared. With that dominant artifact removed, it leaves us with minor imperfections that we can work on.
The first question is: are we losing steps in the motor control? That might cause some of the imperfections here. We had problems with missed steps when we first introduced the motor spindle, so now it is the first thing we check. And the easiest test to run is to run the same program again. In an ideal case, the machine would perfectly duplicate its motion and no new material would be removed. If we had lost steps, the controller's internal coordinate position and the actual tool position would be offset by some amount, causing us to cut the same shape in a slightly different place.
The actual result was somewhere in between. As shown in the picture, we did get a light dusting of powdered MDF from places where the cutter removed a tiny bit of material. It was not consistent enough in any particular direction for us to think steps were lost, which is good news. We are free to continue our CNC exploration and find entirely new problems.
Making Fusion 360 CAM Friendlier To Hobbyist CNC Mills
In parallel with investigating points of weakness within the physical structure, we're also learning how to make Autodesk Fusion 360 CAM friendlier to hobbyist grade CNC mills. We know our project machine, built mostly out of salvaged parts, is not a CNC powerhouse. We now need to tell Fusion 360 how to be kinder to it.
Looking over parameters for tool path generation, the first item we noticed is the default of "Climb Milling". We're not professional machinists, but we knew enough to know this is not a good way to go for this machine. But what if we didn't even have that much knowledge? Thankfully Fusion 360 included a brief explanation accompanying many settings, including the "Sideways Compensation" parameter relevant here.
Key phrase in that explanation: This generally gives a better finish in most metals, but requires good machine rigidity. Our machine is not rigid at all by CNC mill standards and must be switched over to "Conventional Milling". Most real CNC mills in operation today are rigid enough for climb milling, so this was a reasonable default value for Fusion 360 to use, just not for us.
We also wanted to take shallower cuts in the material, as by default Fusion 360 generates code to tell the CNC to plunge into full cutting depth of the cutter. Making full use of all cutting surfaces on the tool is a reasonable default, but that involves removing far too much material at once for our mill. To tell Fusion 360 to take shallower passes, we can select the "Multiple Depths" option.
Unlike the other explanation text, this doesn't mention the setting as a potential compensation to lack of machine rigidity, but it worked. Our next test cut was far more successful.
Z-Axis Rollers Contribute to Tool Chatter
During our chatter-dominated CNC testing session, we used our fingertips to feel around machine structure. Most people's fingertips are sensitive enough for identifying the presence of relative motion between mechanical parts, though only very few people can accurately quantify the distance of that motion. In this case we wanted to know which parts are moving relative to other parts, and our fingers were great for the purpose.
One of the weakest links in our machine rigidity were the four rollers aligning our Z-axis vertical extrusion beam. Two each on left and right sides of the spindle, one above the other. We could feel the vertical extrusion beam vibrating within these rollers clamping them in place.
Examination after our cutting session found the lower two rollers loose. Before this session, all four were tightened up against our vertical beam allowing no movement and enough friction they were difficult to turn by hand. By the end of the session, the lower two could be moved by hand. It appears the upper two held tightly enough to act as a fulcrum, and our cutting tool had enough leverage to move the lower two loose.
Movement of the lower two rollers were a consequence of this modular design built out of aluminum extrusion beams. These rollers are held by square nuts inside the slot of an extrusion, meaning they were held in by friction. When forces build up enough to overcome that friction, these square nuts would slide within their slot, loosening our rollers.
Until we find a better way to arrange our Z-axis, we will have a constant maintenance task of re-tightening these rollers. We also went looking in Fusion 360 CAM for settings to take shallower cuts, and together they made follow-on session a lot more successful.
Problem of Tool Chatter Dominates CNC Session
Obtaining maximum spindle RPM was the last bit of preparatory setup for our next CNC work session. There are still lots of parameters we don't yet understand for Autodesk Fusion 360 CAM, but we knew the fundamental bits and put them in as parameters for G-code generation calculations.
Specify offsets and toolpaths using Fusion CAM, though, is still a skill we're not very practiced at just yet. In the spirit of incremental learning, we try not to let the unknown stop us from experimenting. Mistakes are expected and, as long as nobody gets hurt and nothing is broken (well, even if something is broken) each run should teach us a little more about the process.
And the lesson of the day is tool chatter. Lots of it.
In action the machine really sounds unpleasant, but not quite bad enough to make us think breakage is imminent, so we would let it run in short sessions while we experiment and try to understand its cause. Slowing down our feed rate and adjusting our RPM appeared to have little effect, the variable that mattered was the depth of cut. Even though we had expected MDF to be relatively easy to cut, we now believe the machine is not rigid enough in its current state to cut 3-4mm deep with our 1/4″ cutter. The final cutting pass in this test program (creating the X shape) was only 1mm deep, and that ran quite smoothly even at higher feed rates.
Lessons from this session tells us we can take two parallel approaches: mechanically, we'll need to think of ways to improve machine rigidity. And while that is under development, we'll need to learn how to tell Fusion 360 CAM to take shallower passes.
My machining textbooks talk about importance of rigidity but seeing my janky setup chattering madly really drives the point home. https://t.co/ZJL2jqJ44z
— Roger Cheng (@Regorlas) December 24, 2019
Spindle Clocks In At 11,100 RPM
Once some convenience accessories are in hand, we return to the main business of cutting material. Our biggest unknown at this point is our spindle's maximum speed measured in revolutions per minute (RPM). This is a critical part of calculating the "speeds and feeds" of machining. Yes, we're cutting MDF which will be relatively forgiving, but the point of learning is to practice doing it right.
Our cheap ER11 spindle's product page(*) claimed a maximum speed of 12,000 RPM, but we knew better than to take that at face value. To measure its actual performance, we wanted some sort of non-contact photo tachometer(*). This particular unit was on hand and originally designed for measuring remote control aircraft propeller speeds, and it measured the maximum speed at 11,100 RPM. We'll use 11,000 RPM for our initial calculations. Later we'll measure while it is cutting and see how much its speed drops.
Is this fast? Well, "fast" is always a relative thing. Most people's daily experience with RPM is on their car's dashboard tachometer. In that context it is fast as 11,000 RPM is faster than most normal car engines, though race cars and motorcycle engines can hit that speed. For machine tool purposes, though, this speed is considered on the low side. Especially for small diameter tools that we'll be using. Physically, we are limited by the small ER11 collet for our tool diameter. Plus the machine is not rigid enough to swing a big cutting tool without flexing. And now we know the limitations of spindle speed. Which of these limitations will be the one to actually constrain what we can do with the machine? Let's have another cutting session and find out.
Hex Wrench Holder And Wire Clip For Gantry Extrusion
The first project for designing accessories to mount on the extrusion beam, a holder for ER11 collets, turned out well enough I wanted to continue. Apply some of the lessons learned to create more nice-to-have accessories for the CNC project.
One accessory is a holder for a 5mm hex wrench. This is the size used by the fasteners bolting our gantry's extrusion beams together. There are a set of four bolts, two on the left and two on the right, that we loosen to adjust the height of the gantry. Lowering the gantry lets the cutter cut through our work surface to cut holes for threaded inserts, raising the gantry gives us more Z travel for the work piece. Or we might deliberately trade off Z travel to use a shorter and more rigid gantry for more challenging pieces. We're not sure what the viable combinations are, but we do know we'll need this wrench handy for experimentation.
The other accessory is a wire management clip. Wiring is a perpetual challenge on this project, from finding appropriate component placement to isolating electrical noise. I'm sure electrical challenges will continue to vex us as we proceed. We'll figure out the problems one by one as we go, but one thing is for sure, we'll need a lot of ways to route wires and keep them in place, hence the clips.
Unlike the previous accessories, the wiring clip may be mounted in any orientation. To hold themselves in place, each clip will require additional holding force. To get this force, they are printed slightly more open than their installed configuration. Installation would then require compressing the ring and this tension in the plastic will provide friction against extrusion rail to hold it in place. And while I'm not entirely sure it will be necessary, I added a small flap to keep the wire from sliding out of the ring into the rail slot.
There will be more accessories along the lines of what's been printed so far, but I'm eager to get back to the primary exploration of cutting material.
Collet Holder Clamps To Extrusion
While I was in Onshape CAD designing our goose neck work holding clamps, I also tackled a few other to-do items on the 3D-printable accessory list. The top of the list was building a way to keep extra collets accessible on the machine. Our CNC spindle came packaged with a 1/8″ ER11 collet, which we swapped out for a 1/4″ collet when we wanted a stouter cutter. We didn't have a good place to keep the temporarily unused 1/8″ collet and, rolling around on the tabletop, we were constantly at risk of losing it.
I thought it was a good project to practice designing plastic's flexibility to my advantage instead of constantly seeing it as a disadvantage. I've had several projects along these lines before, but my interest was renewed by Amy Qian's demo board she brought to show off at Supercon.
This is a demo board I made for some #flexures, some of which I have used for projects, others I just think are so cool. #lasercut #delrin pic.twitter.com/5Hdkc5TYJO
— Amy Qian (@amy_makes_stuff) October 28, 2019
There are two ways I wanted to apply this concept. First, I wanted a holding mechanism that can snap into an extrusion rail and stay there without use of tools or fasteners. Second, I wanted a way to hold the collet so that it is held securely by default (not fall out or be dropped easily) but can be removed easily on demand. Again without tools or fasteners.
Here is the first draft of a flexible clip for installation into extrusion beam, this design was too flexible and fell out of the extrusion rail easily. More iterations followed, hunting for the most secure hold possible while still making it possible to insert into the rail.
Separately, I started designing a flexible cover for the collet. The test piece for each mechanism evolved separately until I was happy with both designs, then they were integrated into a single piece incorporating both mechanisms.
With the success of this holder, I took the lessons of a flexible extrusion beam mount and applied the concept to a few additional 3D printed accessories.
3D Printed Goose Neck Clamps For Work Holding
Once we have metal threads securely inserted into our MDF work surface, we could bolt on clamps to hold our work pieces. These clamps are 3D printed because we fully recognize our CNC beginner status and, while we'll do our best to avoid crashing cutting bits into fixtures, it's realistic to plan for the probability that crashes will occur despite our efforts. If we use commodity metal clamps and our carbide cutting tool makes contact it will break our tool. But if our carbide tool contacts a piece of 3D printed plastic it might survive our mistake. We have the luxury of this provision because we're starting easy with scraps of MDF, which requires less forces to hold and to cut than cutting metal.
We started by copying standard step clamps. We weren't sure if the steps could be accurately replicated with 3D printed plastic so it was worth a bit of experimentation to find out. They look very promising but we probably won't use them, because the reason step clamps exist is to have a few set of them that can adjust to various sized work pieces. 3D printing gives us the flexibility to print project-specific fixtures that don't have to compromise for flexibility. This advantage can make up a tiny bit of deficiency inherent in using plastic instead of metal. Hence the second iteration: a single piece clamp shaped like an L designed specifically for the thickness of our test piece of MDF.
Once that was printed and eyeballed on the work table, we moved on to the third iteration: a low profile goose neck clamp tailored for the height of our scrap MDF. Low profile design reduces chance of cutter collision, and it allows us to use shorter and stouter bolts to fasten them to the table. This is what we will use for our first real cutting experiments, alongside other 3D-printed accessories for our CNC project like a collet holder.
Threaded Insert Alignment Tool
We now have a small G-code program that we can call upon to cut holes for self-tapping threaded inserts. We'll cut them as needed for work fixtures on our CNC work table. However, cutting the hole is only part of the process, we had to install the metal insert as well. In order for the resulting threaded hole to be vertical, the inserts have to be held perpendicular to the work surface as we install them. However, the coarse exterior thread makes it difficult to maintain the orientation, made more challenging by the fact the shallow hex socket allows the insert to rotate around the tip of a ball-end hex wrench making it even harder to hold vertical.
We originally had the hypothesis that, given the geometry of the wooden hole, our metal insert will self-align as we start turning it. This may be true for some types of wood but it didn't work for our particular sheet of MDF. If the coarse outer self-tapping thread starts biting at a bad angle, the insert did not self adjust in our experience. It just jams partway down the hole ruining the MDF hole in the process.
To solve this problem, we designed a small 3D-printed plastic tool to help maintain vertical alignment for installation.
The bottom part of this tool helps keep the insert vertical, and the top part keeps the hex wrench vertical. The bottom is mostly flat for the work table surface. I tried adding a small lip to help with hole alignment, but that turned out to be unnecessary. These metal insert can align itself in the XY plane well enough. And once these inserts are in place, we can bolt down our pieces of scrap MDF using custom gooseneck clamps.
CNC Test Program Prepares For Fixtures
My test program exposed an electrical noise issue and helped us track it down to the spindle motor. This was an unplanned but very welcome bonus result on top of its original purpose. It was my first foray into Autodesk Fusion 360 CAM module after following tutorials. I wanted a simple program with few operations, small enough for me to fully understand the G-code output from Fusion 360 post-processor for Grbl. We had scrap pieces of MDF on hand for practice cuts so it wasn't important for the test program to do anything useful. But as I was contemplating work holding for scrap MDF, I realized my first program could be useful after all.
The work surface we installed earlier was also laminated MDF, cut from the same retired treadmill board as the test scraps. Its smooth (well, scratched up, but still relatively flat) top surface is not conducive to any kind of work holding. The original plan was to cut holes by hand with a cordless drill and fasten work pieces using bolts from above fastened by nuts from below the sheet.
Then we had a better idea – use threaded inserts. Counterpart to the heat-set inserts I've been using in my 3D printed plastic(*) projects like Sawppy, there are inserts available for wood. They have a self-tapping coarse thread appropriate for wood on the outside, and a durable machine thread on the inside. Given that our XY table used mostly 1/4″-20 thread, we will continue the trend by using these inserts from McMaster-Carr.
All we needed to put these in was to drill a hole of the specified diameter, and this is a task I can have the machine do for its own work table. I first started with a single hole, walking through each line in the generated G-code to understand what's going on. The results were fine for the insert itself, but the exterior thread damaged surrounding laminate surface during installation.
This lead to extension of the test program, adding a second cutting operation. The first one cut a hole all the way through the surface for the insert, and a second shallower cut to clear surrounding laminate to avoid damage by exterior tread. Once the metal insert was installed with help of an alignment tool, we have a clean fastening point to bolt work pieces to our machine work surface.
Here's footage of a more successful test cut. Plunge speed is still a tad aggressive but otherwise things look quite promising for #SGVHAK CNC project. More details: https://t.co/fINjxWnY5C pic.twitter.com/UY0iO3TlGR
— Roger Cheng (@Regorlas) January 1, 2020
Next Challenge For CNC: Electrical Noise
With a stouter cutter installed, we can experiment with less worry about breaking it. I started generating my own G-code programs from Autodesk Fusion 360 and testing them on the machine. (More about this test program later.) A safety practice I learned in my machining class is to test run a G-code program by intentionally setting a too-high Z offset. This way, when the machine runs through the program, it runs through all the motions but is only moving around in air. This lets us verify the range of motion is as expected. Including making sure it would not exceed either the XY limits of the machine or hit any hold down fixtures that are in the work space.
This process can be repeated any number of times, each time putting the Z a little closer to the workpiece than the last. And even if we don't expect to actually cut material, it's a good idea to power up the spindle just in case the cutter makes contact. While unexpected cuts in the work piece is not great, ramming a non-spinning cutter into the piece is worse.
Running in air is great for finding major problems, but minor issues aren't always visible. It wasn't until I cut into MDF that I found our latest problem: after the test program made its cut, its final position did not match expectations. Running the program again, we expected it to run through the same motion and not remove any new material, but it did. Checking the coordinate display on bCNC, we saw the machine believed itself to have returned to the same position after each run, counter to our physical evidence on hand. What happened?
To diagnose this issue, we tried eliminating individual variables from consideration. Running down the list of possibilities, from loose wires to loose fasteners. The key experiment was running the program without powering up the spindle, at which time all motion tracked as expected. (To protect the endmill from possible impact damage, it was removed from the collet for this test.)
This tells us the source of our unreliable motion was an electrically noisy spindle. A hypothesis is that it degraded our motor controllers' ability to distinguish signal pulses from Grbl, but the precise mechanism is not important. Whatever it was, we need to better protect the system from spindle motor noise. And since every motor will affect nearby electronics to some degree, this is probably not just a consequence of using the lowest bidder on Amazon.
In the immediate term, what we can do for our machine is to make sure the chassis is securely grounded, reroute signal wires further away from the spindle motor subsystem, and add a capacitor across the motor wire terminals to filter some noise. This was not precision tuning, as we just clamped the grounding wire to our gantry and the capacitor was chosen for its voltage tolerance rather than a specific capacitance. Still, the two measures seemed to improve the situation enough to proceed. We know "clean up wiring" is still on our list of technical debt, but this kicks the can a little further down the road and let me return to my test program – cutting holes for work fixtures.
Stouter Cutting Tool For Exploring CNC
Our vertical mill CNC project is barely far along enough for us to run a simple G-code program, so there's a lot we don't yet understand about the machine's capabilities. Pieced together from mostly salvaged parts, we don't exactly have a reference manual we can check for the machine.
What's clear from our first test is that it's easy to accidentally get too aggressive with the machine. The most fragile part in the system is our 1/8″ RotoZip cutting tool. While we want to make sure to wear eye protection when running the machine, we still want to avoid breaking cutters and turning them into sharp high speed projectiles.
To reduce the odds of that happening, further machine testing will use the largest cutting tool we can. Quarter inch shank diameter is just about the widest we can accommodate with our ER11 collet, so I went looking for the shortest quarter inch square nose endmill I can find on Amazon with Prime delivery. (*) McMaster-Carr has higher quality cutters and a wider selection of endmills in general, but they would not have delivered in time for the next available machine work session so I traded off quality for speed.
This is a carbide tool with two flutes. Out of the box, all cutting surfaces looked satisfactorily sharp. Used properly, it should have no problem cutting into our scrap test pieces of MDF. And when used improperly, it should be far less likely to break than our 1/8″ diameter RotoZip cutter. It will serve as the (possibly sacrificial) learning cutter while we explore the rest of our machine, starting with an electrical noise problem.
Scrap MDF Sheet As CNC Working Surface
Once its homing switch was moved to the correct position, our Z-axis is ready to go to work. However, it doesn't have a surface to work on just yet. The XY table forming the heart of this project was originally designed for the purposes of optical inspection, which meant it has a big open space in the middle for cameras and similar optical instruments to see. Big open spaces are not conducive to CNC milling operations!
Fortunately, as part of its original design, this table does have precisely placed mounting points for other equipment. These holes were, in fact, used to bolt the X and Y modules together at right angles to each other. We'll use these mounting points to install a work surface. For precision work, we want something rigid. Ideally something just as strong as the table elements, say maybe a half inch steel plate.
But for learning purposes, we don't need anything so fancy. We just need a reasonably flat surface we can work with. Following the theme, we're going to re-purpose something for the task. This time, it is the main backing board for a retired home treadmill. This piece of laminated MDF had been sitting outdoors for several years and used as a ramp for moving heavy things around. The smooth laminated surface really reduced friction! But it also meant the surfaces are scratched up, and there are signs of water damage at the non-laminated surfaces. Still, it was the biggest, flattest, and most expendable thing on hand for our machine. So it was cut up with [Emily]'s table saw then 12 holes drilled on a drill press. Counter-boring those holes allows the top working surface to remain clear. We're not worried about the cutting tool hitting one of these fasteners — they are outside of range of motion — but it allows flexibility in workplace positioning.
For our first test, we used a scrap piece of wood left from a laser cutter project and a RotoZip cutting bit. The first programmed operation will be the same smiley face test program we used before we even had a Z-axis. Whose G-code, we have now learned, never moved Z-axis at all! There are only spindle on/off codes, likely designed for laser engraving. Which also explained the speed, which pushed the RotoZip bit too fast, bending it quite alarmingly until we turned up the spindle speed. It did all right, but until we get the machine dialed in, what we really should use is a stouter cutting tool.
SGVHAK CNC router makes its first cuts. This has been @Regorlas's pet project for a couple months pic.twitter.com/PMzZjQKUPS
— Emily Velasco (@MLE_Online) December 6, 2019
Reposition CNC Z-Axis Homing Switch
Top of the CNC mill electrical work items list was making sure it had a functioning Emergency Stop button. Once that was completed, the next work item was the Z-axis homing switch. For a vertical mill, we want the Z-axis homing operation to take it to its highest position, furthest away from workpiece. This is reverse of many 3D printers, which home against the print bed. This is because 3D printers have the luxury of starting from an empty print bed as a characteristic of additive manufacturing. A CNC vertical mill, representing subtractive manufacturing, could not make such an assumption since the workspace would have work fixtures and material stock.
Our initial Z-axis homing switch was appropriate for our initial orientation of the mechanism, allowing it to home to the top of its travel. But once it was flipped around, the homing switch is now sensing the bottom of its travel instead. We need to find another mounting position before we could have a good Z axis.
This switch had the luxury of sitting next to the motor and conveniently sensing the approach of the carriage. Its height was sized to match the length of the motor ballscrew coupler, engaging the switch just before the carriage would run into the coupler.
This linear actuator have no convenient location to sense the other end of the range of motion. Since there was no coupler on the other side, a similar mechanism would subtract from valuable range of motion. We didn't have a good place until we installed the spindle motor mount plate, whose top edge gave us an feature we could use to trigger the homing switch.
From that point, it was a matter of running through a few 3D prints to find the correct dimensions to trigger a homing switch while maximizing useful travel distance. Now our Z-axis homes against the top of its range of travel again, let's give it an useful surface to work on.
CNC Physical Controls Panel V2
When I started to build a panel for physical control buttons, I had planned to use arcade console buttons. Big, bright, and durable, they were designed to take a punishment and I thought they would serve well. But before I finished the first version, I had switched to a more task specific button for the emergency stop. I proceeded with arcade buttons for the other two, but [Emily] had a better idea.
She had salvaged some control buttons from retired industrial machinery, so these would be buttons originally designed for the purpose of machinery and not controlling a video game character. They should be given a second life doing their old jobs on a new pieced-together CNC vertical mill.
Using them would require designing and printing another panel. They were smaller in diameter so I thought maybe I could get away with a shim, but even though their smaller diameter required less panel front surface, their mechanism for disassembly and installation actually required more clearance under the panel. As a result I had to rearrange the buttons from forward-back to side-by-side. This is a good thing – the results more closely mimicked that seen on real industrial equipment like this Haas console. My three-button panel is a poor comparison to that full featured beast, but is a lot cheaper.
I also appreciate the black rim on these buttons, making them more difficult to press them accidentally compared to arcade buttons lacking such protection. It was also interesting to note these buttons have provision for three switches underneath, controlling three circuits at once. These, however, only have a single switch in the center slot and given these were salvaged we are unlikely to populate the remaining two slots.
I started the physical button control panel task planning to use three arcade buttons I had on hand. By the time I completed the second version of the panel, no arcade buttons were used but the panel looked better and worked closer to the way they would be on actual machinery. I call that a success, and turned my attention to the Z-axis homing switch.
Our mini CNC vertical mill project now has almost all the basic mechanical components in place. We've done a quick drill test, but that was under manual control. There still several very important things to add before we let the machine run G-code, the top of the list is an "emergency stop" button for when things don't go according to plan. It would also be nice to have physical buttons for "cycle start" and "feed hold", but that is less critical. I soldered some headers earlier in preparation for this, now I need to connect them to physical buttons.
I originally planned to reuse some arcade console buttons I already had on hand, but then realized there is existing convention for emergency stop buttons: once pushed, they stayed pushed until twist to release. They also have a distinct appearance everyone (not just myself) would recognize, and these are things I want to have on my own machine. I bought the cheapest one I found on Amazon (*) and the tactile feel of this unit definitely reflected its low price. If I were to do this again I'd hunt for a more substantial-feeling (and more expensive) alternative. But in the meantime, it seems to work well enough electrically and the low budget nature matches the rest of the project.
For the "Cycle Start" and "Feed Hold" buttons, I continued with the original plan of reusing arcade buttons I had on hand. I have a nice red one for "Feed Hold" but I didn't have a green one for "Cycle Start". I used a yellow one in the meantime, maybe I'll paint it green later.
Then I designed and started printing a panel for these buttons, paying special attention to the emergency stop button's support structure. I want people to be able to slam on this button hard in a panic without breaking anything. Unfortunately, due to an uncooperative 3D printer, I couldn't get a finished print of the panel in time for a work session.
No matter, it was enough for me to begin the wiring work for this project. Obviously I couldn't mount the buttons on the machine until I returned later with a completely printed panel in another session. However, even as I was wrapping up this panel for physical buttons, we were already talking about an upgrade.
CNC Spindle Mounting Plate
Once our new CNC spindle passed initial inspection, it was time to get to work mounting it to our Z-axis linear actuator. Again, the piecemeal nature of this machine meant the parts would not bolt up directly so we'll need to fabricate another adapter plate. This meant cutting another piece off of the same 1/8″ aluminum stock used to mount the Z-axis on our gantry and marking up the dimensions we'd need.
Four holes were drilled to line up with the actuator extrusion beam, and four more drilled to line up with the motor mounting block that was part of the spindle package. The original plans were to use bolts and nuts across the board, but there was a problem with clearance: the motor mounting holes were almost exactly the width of the Z-axis rollers, leaving insufficient clearance for either M6 nut or bolt head.
The obvious solution was to tap M6 threads into the aluminum, avoiding the need for nuts and associated clearance. Unfortunately we had no M6 taps on hand, but [Emily] the resourceful improviser had a trick up her sleeve: We had plenty of M6 steel bolts, and we wanted to tap aluminum. Steel is harder than aluminum, and so with some modifications with the grinder, she turned one of the M6 bolts into a functional M6 tap.
Bolting directly into newly tapped aluminum, our M6 bolts would still just barely scrape the Z-axis roller assembly. Switching to thicker washers gave us the spacing needed to clear the rollers, allowing the spindle to move across the entire range of motion on our Z-axis.
As a quick test, we mounted an 1/8″ drill bit into the spindle and performed the ceremonial first cut of this machine. I was moving the Z-axis via manual jog controls in bCNC, we still have a few more things to take care of before running this machine under automated program control.
Ceremonial first cut via manual jog controls. Still lots to do before we dare set it loose running a G-code program… twitter.com/i/web/status/1…
Roger Cheng (@Regorlas) November 26, 2019
Examining Air Cooled ER11 CNC Spindle
Up until this point, almost everything in the home brew vertical mill CNC project has been salvaged or reused from some previous project. But we've come to the point where the Z-axis drive has been properly configured for a spindle motor… that we don't have. We have smaller lighter motors that aren't strong enough for the job, we have big beefy motors too heavy for our gantry. While we could potentially use a Dremel or a RotoZip as a stepping stone, the decision was made to buy a cheap milling/engraving spindle from Amazon (*) for the project.
The product page proclaims a maximum of 500 Watts and maximum speed of 12,000 revolutions per minute. We'll measure power draw once we can put it to work, and we have tachometers to measure its speed range. We don't expect it to actually hit those numbers, but they seemed reasonable. The part that we were most skeptical about was the proclaimed precision: 0.01-0.03 mm of runout. This is a very high level that we doubted was reasonable in this price range.
The first test after unpacking all components was the obvious basic test: does it spin up? Once we established that it does indeed turn, the second test was then to mount a Starrett dial test indicator (*) to measure its actual runout.
The results were… surprisingly good! When the motor is not under stress and turning freely, it actually stayed within a very tight range. This specific dial test indicator was in Imperial units, measuring a range within +/- 0.0005 inch. This is in the ballpark of +/- 0.0127 mm, so the product listing was not a complete lie.
For practical purposes, though, we'll never have that level of accuracy. There is a lot of flex in the system — from the motor output shaft to ER11 collet — to take us out of that range. A single finger press was enough to bend things beyond the technically-not-wrong runout, so we shouldn't expect very high precision from this spindle after we mount it on our Z-axis and run under real cutting forces.
Turn That Z-Axis Mechanism Around
Fourth iteration of Z-Axis was mounted expediently for the pen plotter test, where we found the ball screw was bent but everything else looked good enough to proceed. Following that success, I will make a better mount for this linear actuator to solve some problems with the quick test configuration we had used.
Problem #1: the test mount was a 3D printed plastic bracket. The best thing that can be said about the rigidity of the mount was that it is better than tape.
Problem #2: old mount leaves long Z-axis mechanism in place, moving the small carriage. Fine for plotters, but for a small vertical CNC mill we want the Z-axis mechanism to move out of the way of the work piece. This means flipping the mechanism around, mounting it by the small carriage so motor moves the entire assembly out of the way.
A scrap piece of aluminum was drafted for this purpose. Holes were drilled by hand for fasteners. The accuracy leaves something to be desired, but the hope is that the machine will eventually get to a point where it can make a superior replacement for itself.
Because the carriage aluminum extrusion beam does not have the same spacing as the gantry aluminum extrusion beam, this plate allows us to bolt them together. Here it is almost ready for installation.
Installation complete. Now when the tool moves up, the rest of the Z-axis moves up and out of the way with it. It is now ready for a CNC spindle.