Trouble with tension adjuster screws on 2012 Kona Unit Here is the drive side screw on my 2012 Kona Unit:


The problem is the screw is very difficult to move and adjust tension.

It's so bad that I stripped the hex head used to adjust the tension, although it may be hard to tell in the photo.


Fortunately, I figured out a workaround to get the screw moving again:


I can snug these nuts together with a couple wrenches, and then wrench one of them to move the desired direction.

It appears that something is going on with the threading. After the screw moves through the frame, the threading on the screw looks different, it is sort of 'flatter'. I could not capture a good photo of this.

My question is, what to do next to fix the problem of the hard-to-adjust screw? I would like to replace the screw itself, at the very least because the hex head is stripped, but also because the threading on the screw could be the problem, or maybe the screw is bent? I just hope it is not the threading on the frame that is causing trouble. Basically, I just need one of the adjuster screws from this:
https://www.probikeshop.com/en/gb/kona-cmphcc-derailleur-hanger/84435.html 
But not the entire hanger assembly. Any ideas where to go to find something? Should I try the hardware store?
I ended up taking the frame into the LBS, and they removed the old bolt from the frame using my work-around. I purchased some replacement bolts from the hardware store, and with some lubricant, they slide into the frame nicely. It seems like the old bolt was damaged, and the frame is fine.