The adjustment knob turned out to be a little bit of an adventure. I did learn something which makes it all worthwhile. I decided early on that I would use Aluminum Bronze for the adjustment screw. It threads like a dream and is strong, hard and slippery. The rounded tip of the adjustment screw bears against the ground top surface of the gage base. I debated adding some type of anti-friction bearing at this point but opted to just use the hard bronze directly on the surface for simplicity. The challenge turned out to be from machinery and tooling limitations.
The first step in a knurling job is to determine the correct diameter to knurl. I measured the pitch on the knurls and calculated a nominal diameter that should be pretty close. After imprinting the pattern several times and adjusting the diameter slighly I had what looked like a winner.
Stay tuned. Its not done yet.