Hey guy's I need some Mach3 guidelines,  I am running an open loop system (no limit switches yet) and when doing a manual tool change is it best to zero out the machine "z" after installing the new tool or just the machine "z"?

Also where is the "touch" feature on Mach3 and is there a tutorial on how to use it or am I doing right in re-setting zero with each tool?

Thanks in advance for any help.

Also has anyone out there have any suggestions on best way to set-up limit switches on a Taig mill?

Thanks in advance for any and all advice.