Big chunk of 4130 -- source needed

Tom,

You may want to specify where you're located. A chunk that large could be reasonably expensive to ship.

You should try tool steel suppliers. I'm not sure if 4130 is a big tooling steel, but I'm faily sure 4140 is sold as a tooling steel.

For my own knowledge, I believe crankshafts are normally forged... Is this for a critical application?

Regards,

Robin

I'm in Albuquerque, NM. A piece this size should weigh about 35 lbs.

I'll give that a shot. 4130 is generally easy to find, just not that big.

Often forged, but they can be machined from solid or cast as well, depending on the design. Forging is a bit impractical in my situation, since I only need one. It's a radial aircraft engine, so I do consider it critical. I'm staying close to the designer's recommendations on this one.

I appreciate your insights.

-Tom

Slightly OT, but is there a reason you're not using 4340?

PPC metals will have it ,I buy a lot of 4140 ht much bigger than what your asking for at very reasonable prices. PPC metals 704 -283 -9122

Yes, because the design calls for 4130 :-)

The crank uses roller and ball bearings, so wear resistance loses some importance. I'd have to check with the designer, but my guess is that, the yield and ultimate tensile strengths of 4130 being good enough, it boils down to impact strength and perhaps fatigue strength.

-Tom