"Bob La Londe" wrote in message
news
I have a box of rust covered bits of square bar I got along with a small
lathe I bought a few years ago. There were some carbide tipped junk junk
bits in the box, but it mostly looked like keystock. I was poking thru the
box the other day looking for one of those pieces of carbide when I noticed
what looked like an actual HSS lathe bit (unground). It had the undercut
on each end that comes on a lot of lathe bits, so I walked it over to the
belt sander and knocked the rust off. A name appeared on the side of it.
I can't recognize the name, but a name appeared none the less. I went
ahead and ground one end to a nice conservative right hand tool and put it
in the HSS bits drawer for my big lathe. Worse comes to worse I'll smear
the end off, but it took some work to grind so I don't think so.

Anyway, after finding that piece I went thru the box again one peice at a
time looking to see if there were any more. Except for the carbide tipped
mystery metal there were no more obvious lathe bits. The rest all looked
to me like precut keystock to me. Slightly rounded edges and a squared
off end with slightly rounded edges. Out of curiosity I grabbed my spring
punch and hit several peices of it with the punch, and then I went and got
that lathe bit and hit it with the spring punch. They all got a very tiny
divot or punch mark, but the mark seemed to be the same size on all of it.
So... is is all this square stock just a different shape of blank HSS bit
or is it the keystock it looks like to me? If it is just keystock can it
be ground and used for lathe bits in a pinch or would it be not quite hard
enough?

I am just curious. I've got a decent selection of insert tooling and a
few pieces of known good HSS ground for stuff I don't have inserts for.




Well, the spring punch test was worthless. The pieces that look like
keystock are easily scratched with a file, and the piece that looked like a
manfacturer lathe blank isn't. I compared it to some M2 blanks I have and
it seemed to skate the file about the same, but the indeterminate results of
the spring punch come immediately to mind.

For those commenting on rust... these came to me in their current
condition. The box was with other bits and pieces on a shelf on a covered
patio. While Arizona is pretty dry its not completely dry.