I am just upgrading my Triac - started as a spindle bearing change and fix an oil leak ....... now it seems to be a full rebuild.

Actually my 3rd upgrade, first was a direct piggyback with mach 3 onto the original stepper system. Then I lost a stepper driver so decided to upgrade the drivers. Latest upgrade is some bearing changes, new spindle VFD, new stepper motors, move lube pump, redirect cables out of the back to seal the base etc.

I've run with the old steppers for 8 years and they have been fine. Only really changing as I've taken the column off to work on the lube system and it's too good an opportunity to not mess around;) If you do change motors, watch out for shaft sizes as the Triac steppers have tiny shafts, as soon as you get into decent sized motors, you will find the pulleys are too small to be bored out and you will have to put bigger pulleys, new belts etc on, which in turn reduces the torque increase benefit!