DIY CNC Router from old printer/scanner parts

[kiwiles]

You didn't say the size you were wanting to pull, though it must be small. Perhaps the best way would be a couple of small air rams one to pull one to clamp. With so many different options in rams these days, it would be a good path to follow - no computer required, simple mechanical automation.
Depending on your cutting arrangement, a rifle cartridge trimmer might be used for clean up and final length trim

les