I'd worry about that little projection on the top piece, right where
it joins the main part of it.
There's going to be a lot of residual stress there when you quench it
in oil. Square shoulders with vastly different thicknesses are a real
However, I don't know what I'd use as an alternative. Going to A-1
might do it, but I don't know.
Maybe. Custom knife makers use it for blades that take some bending
But it doesn't relate to normal tool-steel applications that I know
of. When you use an air-hardening steel in its intended application --
mostly press tooling -- it's for the same reason that I described: a
thin section extending from a thick section, as with lead-frame
punches and dies, and similar tools for punching other electrical
connectors, or any tool that's difficult to quench safely. Those tools
are loaded mostly in compression or straight tension, not in bending.
I'd ask a knife expert about his experience with D-2.
I doubt that it will be getting enough force to risk bending or
breaking (a function of how you temper it after the hardening).
I've used it to make circular punches for producting some parts
from hard felt.
Yes -- D2 like A1 would not need quenching -- just let it sit
out there in the air after heating.
I don't see enough load on this to make a difference. The main
reason for hardening here is to minimize wear at the sear surfaces.
My experience with the sharp edged circular punch driven by a
small flywheel punch press showed no problems. I left it rather hard,
and used a toolpost grinder on the lathe (with proper precision surface
protection, of course) to finish the sharp edge. It mounted by being
threaded some distance back, allowing adjustment of the point at which
it contacts the backing plate. A previous one made of 12L14 was way
too soft and the edge curled under. :-) (Obviously, the threading was
also done prior to hardening. :-)
I don't know the part so I can't judge. I saw the abrupt,
square-shouldered transition from a thick section to a thin section,
and I recognized a quenching hazard with any water- or oil-hardening
steel. That's almost a perfect example of a quenching hazard.
You may overcome it and restore some bending strength with an extended
tempering. That is, if you didn't set up microcracks in the first
place. You're unlikely to know that until the part breaks.
That's a punch application, with compression loading, which is the
intended purpose of punch-and-die tool steels. Among those are the
D-series and the A-series. But W-2 and O-2 are as good, if the wear
isn't a critical issue and there are no quenching hazards.
That's the whole idea of those steels. They're also quite
wear-resistant, but that isn't the basic idea. The idea is to allow
safe quenching with difficult shapes and trasitions.
Ok. Again, I don't know the part or the action.
That sounds like a good application. If I had some D-2 on hand, I'd go
But it doesn't sound like the tool presented any quenching risks. A
water-hardening or oil-hardening steel probably would have worked
about as well. D-2 does have more wear resistance, however.
There is a book "tool steel simplified " which is available on ABE for
a few dollars. It might be something you would want to have.
As I remember it says to start with W1 and go to other tool steels if
W1 does not work.
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