Well, I guess you picked on a piece of air hardening tool steel. Us
blacksmiths use H13 and S7 for chisels, punches, etc.. I think they
have to cool from critical to about 1000°F at a rate of 10° to 25° per
hour to get a full anneal.
I just got done with some correspondence about Atlantic 33 tool
steel. You can harden that one by quenching in water or by just
throwing it on the floor to cool.

Pete Stanaitis
----------------------

Wes wrote:
snip
....Then I decided to just stick a long rod though the cross drilled
holes and
chucking up the pipe and using a two flute end mill to cut out the center area where some
1/4" tubing has to pass.

I *thought* the 1/4" round stock for the tee handle was low carbon steel. Guess it
wasn't.

After I brazed the tee handle in, I tried a 2 flute HSS end mill in a drill chuck on a 22"
swing lathe drilling into the end of this thing clamped in the chuck. Wiped out the end
mill instantly. I guess that tee handle stock was not low carbon steel. Oops.

Found a 8.5 mm carbide drill in my tool box and used that to drill through. Went through
easy. Mystery metal can bite you some times. The strange thing is I brazed in the tee
handles and went to lunch. I'd have thought air cooling would have left the tee handle
fairly soft.

Wes