[TheForge] Re: Timken Case Hardening

[David E. Smucker]

Almost all ball bearings are 52100.  Many ball and roller bearings by SKF, 
Torrington, FAG are also 52100.  SKF and FAG may make some of their very 
large bearings using case hardening.  I would think the same is true for the 
Japanese bearing manufactures but I have no first hand knowledge.  Timken as 
it turns out makes most of the steel for a wide range of manufacturers.  For 
Timken's own bearings they to the best of my knowledge have all been case 
hardened.

That doesn't mean that the Timken bearings are not good for making tools, 
they are.  If forged down the outer layer is still high carbon steel unless 
you grind it off because the case is so deep.  The inside is like a 4120, 
very tough and strong.

But keep in mind and this is a BIG BUT -- like all things made from "scrap" 
they may fail because of defects from the parts service life.  For some, 
this is OK, but others may not want to risk it.

Dave Smucker
----- Original Message ----- 
From: "Ron Childers" <munlaw2 at hcsmail.com>
To: "'Sponsored by ABANA'" <theforge at mailman.qth.net>
Sent: Thursday, March 20, 2008 9:48 AM
Subject: RE: [TheForge] Re: Timken Case Hardening


> Some years ago I made a big knife out of an old axel bearing from a semi. 
> I
> was told it was 52100 and I tempered in oil. It chopped through a 2x4 and
> would still shave, so it must have been pretty good steel. Also made some
> smaller blades out of car axel bearings and big ball bearings; same story.
>
> It must have been dumb luck that the bearings weren't Timpkin. Which
> manufacturers use 52100 for their bearings? Machinery's Handbook must have
> contacted Monmoth, Fag, or some other company for their information on
> bearing steels.
>
> Ron C
>
>
>
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