They sell this rasp file set on Amazon. I THINK I can modify the center round rasp file to make the 6" rotary rasp tool I need to carve into foam. The RPMs don't need to be excessive, and it is just foam. so the side cutting force will be minimal. The bit just needs to plunge as much as six inches into the foam, and then move SIDWAYS. All of the other rotary rasps I found have five inches of smooth round steel shaft with a cutting bit at the end. This will not work, to cut sideways through foam. I ordered two of these sets, to see if I can make this work. If not, they aren't very expensive.