Nicely done! One suggestion for improvement (that could easily be called overcomplication): Add a a stepper motor to control the position of the cutting point and use an end stop sensor (or switch), then just tell the stepper motor to move the required steps to match the desired length. I suppose you could still clamp it down with screws once the length was achieved, so you would not be relying on the stepper motor's holding torque and you could even turn it off. The point is just to have very accurate and repeatable cutting distance. Again, this is obviously overcomplicating the setup and not really necessary. Just a thought.

 

Fantastic !

Before overccomplicating with a stepper control of length and such, maybe machine the piece out of aluminium ? I always found myself cutting into the plastic when using those plastic hand mitre saw guides.

 

Actually, I was thinking of coupling a linear actuator, and a precision scale with an arduino as a base system for shop machines positioning... This seems like another possible implémentation