10 PCS Drills 1.0mm Tungsten Steel Carbide PCB CNC End Mill Engraving Bits Milling Machine Tools

I bought these for a PCB project that never materialized, yet three years later I found them when I needed to drill out a very small hardened steel screw.They absolutely do not tolerate any abuse. I snapped one taking a 0.005" pass across the screw face at high RPM and low travel (manual mill). I snapped another in a setup incident. But taking 0.002" passes got me where I needed to get, slowly. These are TINY, treat them with care!Don't let your workpiece move, use plenty of RPM, and take small passes.

Haven't broken one yet after milling holes and grooves in shells (calcium carbonate). Good quality.

Perfect for drilling into sea shells for crafting. I used to use dental drill bits for this but Amazon won't sell me those anymore. We all know a drill bit won't work on this material. The 1/8 inch drill shank fits perfectly into my Dremel tool and the cutting head cuts very fast through the shells even at it's thickest locations.For those who craft shell jewelry, it perfect!

good for home CNC routers, plywood, wood balsa wood and etc