Good points WM & smallblock.

Here is my suggestion: The DRO's will have calibration setup. The Jensens all do. When you have the dial gages setup for X and Y. You move 1". When it's exact as possible, and repeatable, you then check the DRO. If the DRO does not read 1" you will enter the DRO's offset Cal screens. They will have you complete a process to "calibrate" the DRO and scale it to the measured movement. Once you have that. you then tune Mach3. Move 1" and get Mach3 tuned to 1 inch. It's what I have to do and it came out much better overall...

points: As noted- Mach3 is not a closed loop system like Servos. missed Steps and exacting 1:1 moved on DRO and Mach3 simply is not going to happen (all or most of the time).
Once thing many do: Use of Servo systems and DROs are much better- But still have DRO to Servo/Encoder/Backlash errors. Many put on "magnetic encoders" and feed that into the Servo Drivers/PLC inputs thus replacing the encoder pulses. This means you are not measuring the distance moved via motor encoders, but actual distance the table itself is moving. It's something I want to try w/ linux CNC and scales if I could.... Someday.

Mach 3 cannot perform this type of work thay I know of. There are micro-step server systems as closed loop stepper systems but I have not researched how they do what they do and if Mach3 can even get into managing any offsets ir missed steps.

ENJOY your new rig!

Quote Originally Posted by wreckermech View Post
Ok , lets try to help by not listing the growing pains with shopmaster machines but actually address what might be wrong. For instance ,the tailstock and lathe spindle have different tapers mt3 and mt4 . Next, collets do not have keys but the mill spindle does. And finally the machine dro and mach3 dro WILL NOT MATCH. Why? Because the mechanical dro will read the exact distance traveled to include any ball screw backlash the software dro will only read what mach3 thinks an axis moved. If you lose any steps because stepper motors do not use encoders mach3 will not know and only display what should have happened.