On Jan 4, 2:10*pm, "Ed Huntress" wrote:

Or he's using the wrong machine to drive them. If it's a drill press, you
need some technique to drill hard steels. If it's a hand-held drill motor,
good luck. I'll watch.


Thanks for the response(s). I suspected that cobalt bits came in
different flavors. Three things to help clarify the situation:

1. I'm basing comparative performance on experience in a
manufacturing environment. Once had to remove a fastener made of very
hard material (set screw as I recall). Went through several HSS bits
and barely made a divet. One of the other techs provided me with a
cobalt bit that went through the piece like butter.

2. I am using a hand held drill motor, variable speed, and have tried
several rates from slow to max.

3. These fasteners are used to hold storm shutters onto window
frames, have been in place for a while, and are apparently made of
nuclear-grade steel. I can't imagine why such a hard fastener was
used in the 1st place; I've had less trouble removing a broken head
bolt from a 302 with the engine in the car......

Lopping off the heads with a Dremel leaves the remainder of the screw
in place (obviously) which pins the screen frame to the window frame.
Trades one problem for another.

I have nine shutters to go.

Ernst