Yeep. I've never had a drill bit fail like that. I'd guesstimate a manufacturing defect in the bit itself.
Is there any evidence of a rusty or dirty spot at the beginning or end of the break? it could indicate a crack that wasn't picked up when they hardened the flutes. How about the grain in the break? Does it look like smooth steel or does it have a "gravelly" look to it?
yikes! Bronze and brass are grabby in my experience, and brass will certainly autofeed. Also looks like you had a lot of chatter - did you drill a pilot hole? Sometimes you get better holes just by plowing straight through in one go.
Yes, brass & bronze can grab, help see my previous post (and others) in this thread. Hovever, the hole doesn’t show signs of grabbing, just chatter (as noted by @mattthemuppet2). I suspect a bad bit.
I read on a site dedicated to tool sharpening that most drills that are set up for steel at 7deg and he suggested 4-5deg for brass and bronze. Works good for me and also slower rpm.
For brass (especially) and bronze (sometimes it is the best policy to put a "brass edge" on the cutting face of the drill, that is, a small flat to negate the spiral rake angle, this will eliminate the grabbing/ self feeding.
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