Homing & Hard Limit Switches

[martyscncgarage]

If you use mechanical limit switches for homing on a lathe, unless they are ultra precise and very repeatable, your axis will be off by the deviation.
You should then always take a skim cut on the part and then sent your part zeros from there.

Most commercial machines use a mechanical switch to get it close and then back off of it and look for an encoder index pulse. There are a few drives like DMM DYN4 and DYN2 that will provide the user the index pulse. Emco used to put a sensor on the ball screw pulley to accomplish nearly the same thing.

Marty