Stainless Steel - Cobalt wins!
From: terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
Sent: Saturday, May 30, 1998 3:09 PM
To: Tesla List
Subject: Stainless Steel - Cobalt wins!
I just drilled five nice holes through another stainless steel bowl
without any problem! Thanks for all the suggestions - I used them all!
Here is what I did.
1. Pounded a good center dimple in the metal so the bit wouldn't wander.
2. Used dark metal cutting lubricant.
3. Used Sears Cobalt drill bits #66044 (19.95 for a 10 peice set).
These babies can go through "Stainless steel, chrome, armor plate, titanium
alloys...." - They really do! Apparently, they are 8% cobolt.
4. Drilled at about 15 RPM (very slow) with good pressure.
They sliced right through in about three turns of the bit. Nothing broke or
dulled. Much much better than the last time. Be very sure to were very
good eye protection. The cobalt bits, if they break, literally explode into
zillions of little razor sharp shards. Like those corning ware plates.
Thanks for everyone's suggestions! This was a big problem for me that is
All the best,
At 11:35 PM 5/28/98 -0500, you wrote:
>From: terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
>Sent: Thursday, May 28, 1998 4:50 PM
>Subject: Drilling Stainless Steel
> Like many people, I like to use two large 12 inch salad bowls as a
>top terminal. For my new one, with built in current sensors, I had to drill
>5 holes through the bowls. WOW! was it hard. The stainless steel in those
>things must be very high in chromium content or something. I trashed a
>number of nice drill bits. The titanium nitride bits work for a moment then
>just slide on the surface. If anybody has any better ways to drill nice
>holes through this stuff, I would love to know about it.
> Terry Fritz