Hello,
We are building a dual miter saw station with computer controlled miter stops. The movable stop on the left saw will be X axis and the stop on the right saw will be the y axis. Both saws will be set to opposite 45 degree miters. We are constructing this machine to cut aluminum extrusions to length for door frames. This station is to be about 24' when completed. Both saws will be controlled by Mach3 software. It will be similar to the one shown here: https://www.youtube.com/watch?v=dHXoMG2s5yE

Ours of course will be more more of a commercial nature in design. We will be using an R&P system for the miter saw stops.

My question is this: We will be using a pneumatic clamping system to hold down the extrusion as it being mitered. Once the hold-down is engaged on the work piece, is there any way to trigger a micro-switch so that the miter stop cannot be moved while the clamps are engaged. My concern is that accidental operator error could move the stop tighter against the clamped piece and stall and cause damage to the stepper motor.

Any ideas will be greatly appreciated.

Best Regards,
Brian

You will not damage the stepper, steppers can be stalled without harm, they squeal a lot

The design of the switch totally depends on the design of the hold-down, there is always room to fit a sensor or switch

Of course, if you just trust the hold down to do its job, the rest is just simple logic - "do not move while hold-down output is on", sure that can be done within Mach3

It might not damage the stepper motor, but would definitely loose position and require re-referencing.

Both saws will be controlled by Mach3 software.

Do you mean the actual sawing will be on mechanized rails of sorts as an axis under Mach3 control ? Or manual ... like in the video ?

If like the video, you could include a pressure switch in the pneumatic clamp circuit tied to a Mach3 input to inhibit any action if any pressure is applied to the clamps.
Included in you button scripts could also display an alert message. "Move  Prohibited ... Clamps Active"

Fair enough, I was also presuming the hold-down clamps would be engaged by Mach3, thats what i would do anyway, then the logic is all internal and no inputs needed.