Here are the test procedure and results from measuring the X and Y axis. As you can see all the results from moving 1” came out to be 0.996” on all three tests that were ran on each axis. I am using ½” 10 TPI 1 start Acme rod. All three axis were cut from one piece of rod. This is not a high precision piece of iron.

After setup I did not have to touch the indicator, it came back to zero every time.

I will try and attach the spreadsheet with test details.

What do you think of the test results?

What would be my next step?

Regards

Hager

I would be suspicious of the accuracy of whatever indicator you're measuring. Either that, or your screws are not reall exactly 10TPI. Do the measurements again, using a different indicator. If you get the same result, then you're screws are off, and the solution is to simply re-calculate steps/inch based on 10 turns = 0.996 inches. If you get a different result, (hopefully 1.000"), then you know you have at least one lousy indicator.

Regards,

Ray L.