Originally posted by tim60 One job I had to do was drill a 3/8" hole in a largel ingot of lead. Real hard. The lead was so malleable it formed long snakes that filled the drill flutes and the drill did not cut if off at the front end. Real hard to extract the drill bit from the lead.
Surely (Shirley) I was not using the best drill bit.
a spritz of wd-40 or some silicone- or Teflon-based lube would have worked
I helped drill the weights for a cabinet clock that used lead ingots and that was the solution
works on brass and aluminum which aren't malleable but "sticky" as well
the second time I used brass tubing
heated it
drove it through the two inches of lead...lickety-split
when the tube cooled it was soldered in
cut off the excess tubing
peened over the ends
had much more abrasion resistant pivot for a shackle to fit in
after all of that, a neighbor suggested using the old crappy stamped sheet metal style of pilot+countersink bits
he was correct...with no flutes...no clogs