Because the plane is designed to go cross-grain, it needs a nicker.
Because I didn't have one, I needed to make one.
I spent the better part of half a day cutting and filing this particular bit out of a piece of O-1 tool steel that I had kicking around in a drawer somewhere.
(Yes, I happened to have tool steel kicking around in a drawer. I'm aware that this is possibly not typical behavior. I live with it.)
At that point, I had to dig out my notes from a class that I took with Larry Williams back in 2005, covering heat treatment.
I used a (borrowed, but they're not too expensive) Mapp gas torch to heat treat the bit on the nicker. I also found out the hard way that there's a reason to do this on fire brick, as opposed to bare concrete.
Anyway, the notes say, heat the tang to black. Then heat the bevel side of the bit to cherry red, flip over, continue to heat until spots of flux appear on the surface of the steel. Then quench in oil, stirring the oil with the steel for about a minute or so, holding the piece vertical, to avoid warping.
After that, the steel is hard, but brittle. So, the next step is to temper the blade by baking at 350 for at least an hour. That should soften it up enough to make it usable.
So... yeah. I made a heat treated blade for my dovetail plane. There's a little bit of the beginner in me that's squealing in delight. It may not be a major accomplishment on the grand scale. But it's not something most folks get to do every day, either.
Read Part 1.
Read Part 2.
Read Part 4.
Read Part 5.
The Plane In Use.
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