After reading the article in the latest MEW I thought I would check the Y-axis leadscrew of my chinese mill against the cheap chinese DRO I have fitted.
I noted the DRO reading for every full revolution of the leadscrew for about 400 mm ie., 100 points. According to the DRO the the leadscrew is short by 1 part in 2000 with a random error of plus or minus one thou.
Given the low workshop temperature (about 15C) at present and the high temperature in chinese factories I have visited in the past perhaps the error is due to thermal expansion/contraction of the leadscrew? Any ideas as to how significant this effect would be?
Russell.