Question: I have seen videos related to cutting circles on a table saw. I would love to try this but I am hesitant to make a jig that, to me, seems to be extremely dangerous. [Here is a video](https://youtu.be/z-xhYnWDCd0?t=33) of Matthias Wandel using his jig to cut a rabbet into the circle, which seems like it'd be even scarier.

How does one make this jig and do so safely? Are there any gotchas that should be considered when executing this jig?

Answer: 
Take a sled and add a pivot as far away from the blade as you want your radius. (riving knife and guards can remain in place)

As preparation rough cut your piece on the band-saw. 

![http://woodgears.ca/bandsaw/cut_outline.jpg](https://i.stack.imgur.com/jskvv.jpg)  

[source](http://woodgears.ca/bandsaw/wheels.html)

Then put your piece on the sled and attach it to the pivot. Clamp it down to avoid the piece rotating while you are cutting and make a cut. Unclamp, rotate, clamp and cut again; rinse and repeat until it is round.

To get it perfectly round while not rotating the wood against the blade is nearly impossible. The last passes would require very accurate turns.

Instead if you have a motor and some shaft and bearings handy you can attach you can attach a pully to the wheel and work on it like a lathe.

![enter image description here](https://i.stack.imgur.com/qcWBv.jpg)  

[source](http://woodgears.ca/bandmill/wheels.html)

The main advantage of this last step is that you are turning the wheel on its own axle so even if you make a mistake when mounting the bearings/putting it on the shaft you can true out the wobble.
I'm of the same mind, Peter. All the plans I've seen require removal of too much safety equipment. 

There are too many other tools that would suffice- from a band saw for smaller circles to a jig saw or router on a commercial or shop made trammel for large ones.

e.g.

Band saw-
![band saw circle jig](https://i.stack.imgur.com/fyBVj.jpg)

Or router..
![Router circle jig](https://i.stack.imgur.com/gS2EE.jpg) 

Or for a jig saw..

![jigsaw](https://i.stack.imgur.com/hu0rj.jpg)