Axis scaling errors - is this just to be expected with C7 screws?

[JAZZCNC]

That's why I'd be wary of entering anything other than the calculated value for step/mm, as it will compensate only for the portion you measure, on average. You need to be very confident of the measurement accuracy to do this.

I don't exactly agree with this but at same time I do.?
Completely agree that not good idea to use over short distance but if done over the full length or large portion of screw then can set the machine up very accurately, much more than working to fixed calculated values which don't account for screw or other factors like belts/pulleys.
However to do this requires very accurate measuring device done over long distance.

I set machines up using Glass linear scales to verify movement and find that if using timing belts/pulleys this is only way to very accurately set machine up as the calculated values often don't get it spot on. Even when direct mounted there can be some error but to much lesser degree.

So case of Yes and No to me also how accurate or Anal you want to get about it.??


However in this case I'm 99% sure the issue is compulation of mechanical and design weakness.