Dave Hinz wrote:
Building a project out of a piece of 4140 prehard. The local custom
metalcutting shop provided the steel. Problem is, it's magnetic. Not
just a little magnetic, it's "you could use this thing to pick up nails,
small children, and battleships" magnetic. I asked them if they have a
demag ring, they don't (and were surprised but will check their stock...
ok, great, but doesn't help me much at the moment).

So how do I demag this sucker? I know that heat would do it, but I
don't want to mess up my hardening. I know mechanical impact can redue
it, but I don't know if that's one of those "theoretical but not
practical" things, or if it'd work. So, simple question - can I just
smack the (un-machined) end of this sucker with a hammer a bunch of
times and get it down to tolerable, or do I need to find someone with
degaussing apparatus of some sort, or am I SOL? It's annoying, to say
the least, to have every chip re-attach itself to the work, invariably
on the layout lines that I'm trying to see.

Thanks,
Dave Hinz



We used a big 3 phase motor with the rotor removed and hooked up the
windings to 110AC. You just pass the metal through the opening where
the rotor was and it will be demagnitized.

John