message is on behalf of someone else.
they have a set of cheap cinese morese centres (MT2) which they want to cut
down so they can convert the centres to arbors.
wht would be the recommended annealing method?
I made an MT2 tail soft enough to cut the tang off with a hacksaw by putting
it in a swirl-torch flame (air-propane) - it got dull red hot and I let it
air cool. Blueing went about 1 inch up the taper. No trouble sawing it; this
was a "Grotz" brand, sold by BusyBee tools, cheap.
Personally, my choice would be (and was) to buy blank MT-2
arbors. (I got mine from Grand Tools, FWIW.) They have the standard
MT-2 shank and tang, and then end with about 1" length of 1" diameter
But since they already have the Chinese centers, the advice
which you have already received from others sounds good. I particularly
like the capped copper pipe mentioned -- and I would suggest putting
some paper in before capping it, so it will burn up and use up the
oxygen trapped in there before it can create scale.
Heat it above the critical temperature and then cool it slower than the
critical rate. Or in lay terms- heat it red hot and then cool it very
slow. If you are using an oven just shut it down and leave it to cool in
the oven. If you are using a torch just move the flame back slowly over
a minute or so and allow it to air cool the rest of the way.