Is it possible for the spindle to loose timing after threading?
We ran an OD thread then after cycle was complete, we measured the part, made an ajustment in X axis in the tool data, ran it again and it's noticably shifted (out of time with original cut, basically scrap now)
How do you make adjustments to the size while still in chuck?
It's programed in Mazatrol, QT 15N lathe, It's a stepless spindle I'm thinking.