On May 13, 5:55*pm, Molly Brown wrote:
I usually somehow manage to remove a broken bolt but in this instance
that is not an option so I need to drill it out. The bolt is probably
hardened steel and I am using a drill press at 300 RPM, a cobalt bit,
and metal cutting oil. I have had the drill press arm bungee tied for
the past few hours and all I got was about a millimeter. Is this
normal or am I doing something wrong?

After doing extensive research here is how I drilled-out a hardened
steel bolt:

1. Use a drill press that has a vise. It says to use a hydraulic chuck
instead of a clamping chuck but I didn’t have a hydraulic chuck; maybe
I got lucky that it worked for me.
2. Set the drill for 220 RPM
3. Use lots of cutting oil.
4. Feed the drill VERY slowly and no more than several seconds at a
time. Clean out bits of steel with a paper towel between periods of
cutting; maybe it’s not necessary but doesn’t hurt. Keep the room as
quit as possible so you can hear it cutting.
5. Use a solid carbide bit. Not carbide coated or carbide tipped but
solid carbide which costs about $22.00 for a ¼” diameter bit. The bit
is very brittle and will break very easily and can never be sharpened.
Do not expect it to give at all. You will not find a solid carbide bit
in any hardware store so don’t even ask because they won’t even know
what you’re talking about. You will need to go to an industrial tool
supplier or the internet.

I must be the first to post these instructions on the internet because
I haven’t seen another one with this much detail. Bully for me.