PDA

View Full Version : Need help Substituting a metal ???



hoof
08-22-2010, 07:47 PM
Hello folks, I am looking to duplicate a part that was made from a forging. I have exhausted all avenues getting information from the OEM. It is a eccentric crank for a press brake. I'm guessing it needs both sheer and tortional strength. This part is going to be a bit of a test for me as I have only played with metal cutting stuff as a hobby. The pin that was broken weighs about 120 pounds. I hope I only have to do this job one time. The maker of this machine is Cyril Bath and they have been out of business since the early seventies. The good news is no one was injured when this press was actuated with the tool set wrong. The forst order of bussiness is to install a keys switch to keep the unauthorized from doing this again. I appreciate any suggestions.

Thanks

Ray

oldbikerdude37
08-22-2010, 08:04 PM
8630 is a Nickel-chromium-molybdenum steel thats tough but 4140 may be better.

Rich Carlstedt
08-22-2010, 08:43 PM
Since its a steel forging, it means that strength is important, and
a non-forged part will be larger to compensate for the lack of forged grain structure.
Take the broken part to metal lab for analysis, it pays when you have critical safety parts and you sound like safety is as important as it should be!
Alternatively, some scrap yards have a hand held metal analyser that can also tell you what the metal is.
I would suspect a 4130 or 4140 with a 28 to 32 RC hardness ( 140 K tensile), but that is a guess

Rich

winchman
08-22-2010, 08:46 PM
It would probably help to know what the part looks like. Any pics?

ADGO_Racing
08-22-2010, 08:47 PM
About 10 years ago when we were still a job shop, I had a guy who carried a line of parts for various presses see me about making crankshafts for presses. He was using 4140 HT.