[Castle1]

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.

[little bubba]

I've never had an unsolvable problem with it double threading after an offset.

Did you change your SFM, or spindle speed before you ran it again? The acceleration of the Z axis will screw you up. I learned that one real quick.

The other thing that has happened is the operator who knew they should check the thread before it came out of the machine, took it out anyways, then stuffed it back in.

[Castle1]

Yep, Changed sfm. I was thinking about the manual machines in the shop, I can change rpm as long as I dont take out the feed rate levers etc... Any worries about rotating part then (still clamped in chuck) while checking thread etc?
thanks,
Steve