Go to www.mcmaster.com, put tool steel in the search box, and then click on
more info at the top of the page to get some data tables on steels,
including tool steels. They list the min yield strength of O1 as 50 ksi and
A2 as 51 ksi. For Rockwell hardness, O1 is B85 unhardened and C65 hardened,
and A2 is B88 and C65, respectively. At the bottom of that screen are two
more more info buttons. Hope this helps.

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Regards,
Carl Ijames
"Doug White" wrote in message
. ..

I need to make a replacement pin for a Russian target pistol (a TOZ-35M
free pistol). The pin is the pivot for the Martini action block.

The pistol has been quite functional for a couple of years using the stem
of a cotton swab, but it looks tacky. I don't think the pin needs to be
hardened, but the official one has a groove in it that a spring detent
snaps into. That will wear over time if the pin is too soft.

I'm going to order some 4mm drill rod, and have the option of A2 or O1
steel. If I don't bother hardening it, is there any advantage to A2? I
can't seem to find any info on what the hardness of the two are in their
annealed condition. A2 has some chomium in it, and I'm guessing it might
hold up a tiny bit better.

Thanks!

Doug White