Originally Posted by beaugator
Thats to go all the way through and to make sure it doesn't break off in the hole. It's when the bit gets dull that you use too much pressure trying to finish the hole that breaks the bit off..... along with break through torque. As was stated in an earlier post... go easy when you're almost through the other side of the bolt. Be sure to pull the bit out often to clear the flutes. That will help it go through better as well. Cobalt bits don't need to be lubed for this application. They won't start to cut until they get some heat in them. You regulate the heat by pulling it out to clear it and wait a few seconds before you continue. Trust me on this one.... I've drilled more holes in my life than any sane person should ever have to..... somewhere over 250K in 33 years!
You buy 8000 bits per year!?!?!