granite tile mounting plug - 5 mm hole, M3 thread

thingiverse

How do you attach a printer to a granite tile? Simply use brackets - see https://www.thingiverse.com/thing:2859409. But how do you get screws into the plate? Typically, one would drill a hole, insert a nylon plug and screw it in with a wood screw. However, after drilling holes, I ended up with four large craters at the back of my tile - not entirely unexpected - and didn't want to risk breaking it completely by using expansion plugs. The next best option would have been to cement threaded rods into the holes and secure the mounting clips with nuts on those rods. But this would have required lifting the printer over these rods whenever I had to remove it from the base plate, which wasn't ideal. So, I needed something that could fit in these holes, accept a screw inside and be stuck to the hole itself. Essentially, a tube with a thread on the inside and some sort of wing on the base to prevent it from rotating in the hole. I'd insert it from the back, fill the craters with mortar, and be good to go. My test print went smoothly, at 0.1 mm resolution I was able to (with a bit of force) push an M3 screw into what Fusion 360 said should be an M3 hole. Four plugs are printing right now, and I'll mortar them in on the weekend.