191. No more drill bit flexing and breaking

**Make Things** · Nov 27, 2023, 03:19 PM

**desbromilow** · Nov 27, 2023, 09:26 PM

NOT sure about this.... I was always led to believe that drill shanks are softer (annealed HSS) compared to the harder flutes. Gripping a hardened flute seems like a recipe for cracking/chipping the flute, or damaging the chuck jaws.

thoughts?

**Make Things** · Nov 27, 2023, 11:08 PM

Originally Posted by desbromilow

NOT sure about this.... I was always led to believe that drill shanks are softer (annealed HSS) compared to the harder flutes. Gripping a hardened flute seems like a recipe for cracking/chipping the flute, or damaging the chuck jaws.

thoughts?

I think you're definitely correct that the shanks are softer, but how hard are you bearing down on the chuck? In my own experience, I have never damaged a flute or the chuck jaws. But I would assume the chuck jaws are hardened themselves, so the biggest concern would be the drill bits. Gripping them lower prevents them from wandering which can bend or break the bits in the long run.

**NeiljohnUK** · Nov 28, 2023, 07:29 AM

Originally Posted by desbromilow

NOT sure about this.... I was always led to believe that drill shanks are softer (annealed HSS) compared to the harder flutes. Gripping a hardened flute seems like a recipe for cracking/chipping the flute, or damaging the chuck jaws.

thoughts?

Stub drills exist for this reason, many/most CNC drilling jobs are done with a stub drill to start with if not the whole job. You can create stub drills from old worn/broken jobber bits, though the split point most commercial stub bits are made helps avoid wander even more.