Ok, I have read until I am nearly blind. Learned a ton, but still a bit short on what I need.

I am running TurboCNC with a Xylotex board. The HF mill has 6 inch lead screws. The Xylotex board is suppose to be set for 1/8 micro. I have geared down to 4 to 1.

What should the scalling be set to? Using the calc screen, I set step/Rev at 1600, lead 6, microstep (what is this?) 1, and Gear ration 4 to 1.

With this setting, a command to move .1 moves about .095. Repeated moves generate the same result. I changed the pulse width from 2 to 10 and this changed nothing.

Thoughts, suggestions?

Lead = 1/turns per inch. Microstep should be 8 on a Xylotex by default. And step per rev = 200. By using 1600 and 1 for microstep, you have the same thing. THe pulse width changes the length of the signal, it doesn't affect distance. Keep it around 2-3 if it works OK.

Lead = 1/turns per inch.
Lost me on this one. The lead screw is suppose to be 6 turns per inch. The scales show 1 turn = .167.

OK. You had it correct the first time. You either have some minor error in your gearing, or your screw.

.0000260417 Is what you should have, correct? divide .1 by .095, which is 1.0526315. Multiply 1.0526315 x .0000260417 and enter this into the scale. 0.0002741231

This should correct the error. I would actually try doing some longer moves to figure out the actual difference, as the screw may have error in the particular spot you are measuring. Try different places on the machine, and average them.

the screw may have error in the particular spot you are measuring.

This is probably the issue. I will measure the distance over 75% of the travel and average it from there.

Thanks for the tips. I think I will cut some metal today. :)