calibration

[Jonathan]

I ALWAYS use the Mach wizzard because it works of the actual movement travelled

No, you measure the distance travelled. But we can't ever measure it with zero tolerance, so it will always be slightly out. For most people that doesn't matter, but that doesn't make it all-right in my opinion.

I think it's because the pulley diameters are not exactly to spec and therefore the ratio is different.

Definitely not true. The only way the diameters could be different is if the number of teeth is different. If you look at the tolerances for the pulleys it's not possible for such a large error. Also having made several pulleys it's obvious that if you get the diameter out by the smallest amount the belt simply doesn't mesh with the pulley, so if the diameter was wrong the pulley wouldn't work.

James did you count both pulleys on Y and Z? It just seems too big a co-incidence that the number is so very close to making it 28T.

[JAZZCNC]

Ok "Boy wonder" your the "Man" for calc's All I know is how to make it work correct.! :dance: