Most people know that it's hard to drill a hole in rubber. The rubber stretches instead of being cut and tends to tear. Even freezing the rubber doesn't help. The traditional technique is to use a cork borer, which is a round razor blade on a handle. An alternative is a rubber core drill. But if you only need one or two small holes, you can also use a Dremel or Proxxon tool. The high speed prevents the rubber from returning to its original shape while being cut.
At 20,000 rpm the rubber never tried to grab any of the cutting bits, but some of them produced a fair amount of smoke. This can be avoided by using a lower speed or spraying the piece with water. The black ¼-inch rubber in the image below shows that some worked and some didn't.
Standard cobalt drill bit in a drill press (#6, 0.206 in.) The rubber piece grabbed the drill bit and wrapped around it. Clamping the rubber down was not easy. I eventually got a hole, but it was ragged and the wrong size.
Small 8-edge routing bit A little slow, but made a perfectly round hole.
2-edge straight router bit Also made a perfectly round hole. Some smoking.
Round engraving bit Very fast, perfectly round hole.
Pointy carving / engraving bit Slow, made an irregular hole and lots of smoke.
TiN-coated carving bit Doesn't cut, creates a lot of heat and smoke. The cutter turns brown.
Dremel drill bit 0.0768 in. Became hot, but made a hole.
Dremel drill bit 0.125 in. Became hot, but made a hole, not as good as the router bit
Spiral roto-zip drywall bit Very slow, made a clean hole but lots of smoke. Wear a gas mask.
Tungsten carbide carving bit Did not cut.
aug 30 2026, 1:25 pm
