Go to this page and scroll down to where it says
Stripper blots/Shoulder screws by Unbrako.
The pic to the right is what they are like except for size that is
I used a screw with a .312 diameter and .375 shoulder with 1/4-20 threads.
The screw is high speed steel and it locks down against the aluminum support. The nylon wheel was drilled to about .315 and has a stainless washer on each side of it.
There is no way the roller would ever seize as far as I can see!
Also if you want it faster you can always put a VERY SMALL drop of light oil(rocket fuel) or some teflon spray onto the shoulder.
here is the webpage. It will open in Adobe Acrobat!
Hope this gives you a better understanding on how the bolt works!
http://www.mscdirect.com/PDF.process?pdf=1943&Keyword=Y
Russ
Threaded Mode