Printed hole cleaner/file

use an 8mm threaded rod, around 3/4th a foot long (cutoff scrap from making printer), grind one end of it into a semi pointed code (not sharp), then take a dremel and cut lines into the cone going long ways into the threaded rod, around 5mm in. After that, just put a nut on the end that isnt grinded down, and slide it through the handle, then attach a washer and nut onto threaded rod, and tighten it down so it's very tight, so nothing will move.

I use it for screwing into the holes on printed bearings and parts for when Im making my reprap printer parts, for when they wont fit the rods. Just screw it in, and it'll cut into the plastic that is too small making way for the screw rod, which will keep screwing the rod in till the part hits the nut/washer on the handle, then if you keep turning it, it'll clean out all of the extra plastic that went between the threads acting as a drill bit almost, but you have more control over it.

Then after the screw is cleaned out and you can move