This is a saw-style tool for hot-wire foam cutting (NiChrome wire sold separately).
WIP: The edges need to be moved a bit further from the screw holes, my first print started to tear in a few places after I put in the screws.
I'm still experimenting with the power source. A 5V 1A USB wall wart, gets it hot enough for a slow cut. 6.5V from a pack of 4 AAAs seemed to do the trick, but it didn't last as the pack's voltage dropped pretty quickly.
The holes are 3mm in diameter. Any self tapping screws that fit snugly to that should do the trick.
The screws I used were countersunk, so I found some hex nuts that worked well to clamp my NiChrome against the taper.