Quote Originally Posted by ncollar View Post
All that math is alright if that is the way you do it. I would put a mark on the face of the knob with a marker and a DTI, make one revolution of knob, then figure out how many lines you would like to put on the dial. If one rev is .0010 then 10 lines would be .0001 per line. No math to error.
Nelson
The problem with that approach is that if you want one full revolution to be some "nice" number (e.g. 0.010) rather than some inconvenient increment, you must take account of the mathematics of the design. (Besides, you'll never learn any math if you avoid opportunities to use it in practical problems.)

The brass wedge will rise by:

P * tan(A)

for every revolution of the screw driving the steel wedge. Here

P = screw pitch = 1/tpi
A = wedge angle

Let H = desired rise for every revolution of adjusting screw. Then we can solve for the required wedge angle...

H = P * tan(A)

A = arctan (H/P)

As an example, for ten thousandths rise per revolution of an 18 tpi screw, we have...

H = 0.010
P = 1/18

A = arctan (0.18) = 10.2 deg