"Jim Wilson" wrote in message
ink.net...
Ed Huntress wrote...

1/4" is 'way too thick for a plane iron (for a hand plane, that is), and
you
shouldn't be losing much, if any, stock to oxidation anyway.

Right on the second point, but 1/4" is an excellent thickness for a plane
iron, especially if you're making a wooden-body plane. Unless you are
making a replacement iron for a Norris- or Bailey-style plane and have
clearance issues, thicker up to about 1/4" is almost always better, for a
variety of reasons.

If he's making his own planes, he can make them as thick as he wants to, and
I agree, thicker is better. My old wooden-bodied Stanleys actually use
thinner blades than modern ones, but I've relieved the mouths so they can
take greater thicknesses, because the thin ones chatter.

But I think what he was referring to was making them thick and then grinding
off the bark and scale. Even if you do that, you'll have to do one hell of a
lot of grinding to get that iron to fit in any normal commercial plane.


What you want to do is to protect your steel from oxidation. You
shouldn't
be heating tool steel to its transition temperature in plain air.

For sure. Assuming (!) the OP doesn't have access to a heat-treat oven
and is using some type of propane setup, an easy way to limit oxidation
is to choke off the forge openings to create a slightly reducing
atmosphere. This is easily achieved even in a simple coffee-can forge
fired by a propane torch.

What does a coffee-can forge look like? It sounds like something that's
right in my price range. g

Ed Huntress


Tempering should not cause noticable oxidation, although it will change
the surface color due to a very thin oxide layer. That doesn't require a
thicker blade; if you object to the color, you can polish it off or, in
most cases, you can etch it off with a quick wipe of Naval Jelly or
other
source of phospohoric acid.

The flattening and honing will polish some of the face (back) and
probably all of the bezel. Like Ed said, the oxidation color doesn't hurt
anything, but it does buff off quickly with a Maroon Scotch-Brite pad
(7447), if you want.

You should do something either to protect the surface of the steel or to
raise the carbon potential in your furnace when you're heating it to
harden
it. This may be as simple as coating your steel with ordinary bar-type
laundry soap before sticking it in the furnace.

That's another good idea, and it seems to help release the crust from
quenching in oil, too.

Jim