Jerry,
Some additional info:
My screws have a major diameter of .060" and minor of .050" which I believe would make them a #0 size. The minor is a bit big and the standard for #0's seems to be a 80 pitch. Your Lyman guy is right on the pitch. I put my thread gauge on a magnet so that the screw stayed in place on the gauge and then using a 10x loupe could finally resolve the pitch issue. It is a 64 tpi.
![](http://i818.photobucket.com/albums/zz110/daiggerd/lyman_48_screw_zpsv3ajb9np.jpg)
Also discovered that this head type is fillister and they come in a flat or round style. Here is am image of my sight and these screws. As you can see they are mismatched for head type because I didn't notice the difference when Michael made them available. Both types, however, protrude sufficiently to capture the detent spring when under tension from the knob.
![](http://i818.photobucket.com/albums/zz110/daiggerd/lyman_48_screws_zpsomhipv8e.jpg)
This company has miniature screws and although they don't have the proper one they might know of a source:
http://jimorrisco.com/miniature-screws-and-fasteners/miniature-screws.htmlDennis