Carbide Burr Set 8pcs 1/4 Inch Shank Diameter Double Cut Rotary Files Metal Grinding Polishing Carving Tool Drill Bits for Die Grinder Kits

bon produit et bon service

These are very tough bits but not capable of grinding through hardened steel. I breach old payphones as a hobby, which have two locks (top for phone, bottom lock for coin box). The bottom lock is super hardened steel and these did nothing to it. However they shredded the top lock and had no signs of wear at all. The one pic on here of the worn bit looks like it was somehow spun in reverse (must not have used a real die grinder for the bit) or maybe didn’t use any cutting lube. Even on the hardened steel despite not making any considerable dents, the bits still didn’t get damaged or worn.It would have taken 12+ hours of grinding away at the hardened steel with these and still not sure they would be able to do it. Not any fault of the bits. It’s more a testament to those dang locks! Lol. Hardness matters. Perhaps diamond tipped ones are what I’m looking for.

used this for 3 months now and they work good one has worn down a bit but it still works and is still cheaper to get a whole new set then just get one

I used one of these to elongate 4 holes in 1/2 steel. Cut great and still sharp. If you need to cut steel buy these, they work good at a great price. I have paid $15 for just one at the supply store. These are just as good.

They worked very well had no problem boring out a bigger hole on 1/8 piece of steel.