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MotoSook MotoSook is offline
Somewhere in the Midwest
 
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Join Date: Oct 2001
Location: In the barn!
Posts: 12,473
Dang! I love it when it gets hot...so I have to throw in my two cents..

If Tristan's torque wrench is off (it would have to be a lot) why didn't the other bolts fail? It seems to be a simple issue of some bad bolts.

I would love to visit a shop that does 100% x-ray testing on every bolt that comes off the line. If there is such a shop, I would love to see how they do it. Even with the great "Six-sigma" hype in QC, you won't find a shop that x-rays 100% of the parts.

Any of the processes in the manufacturing of the bolts can cause a defect and since the QC checks are random samplings, some bad batches get out. A random part(s)/bolt(s) that was tested from that batch may not have failed the test(s), so that batch gets out. Even the test may not be perfect. (I have performed lab testing of bolt and metal failure, and the results never gave me the confidence that I could predict when and how a bolt will fail...at least not with 100% confidence!)

I've had bolts fail in the field after all the testing and all the QC by the manufacturer. The bolts are used to hold 1500+ psig of pressure on a pipeline. You can bet that the bolts were under a QC program. But the real world is not perfect and defective parts make it out to the field.

Jack has some good things to say now and then so I peruse his posts for the good stuff, but I don't think Jack's thinking broadly enough here.

And serious racers don't have to spend $50,000 on an engine, just the ones with lots of money or a fat sponsor
Old 03-29-2004, 11:53 AM
  Pelican Parts Technical Article Directory    Reply With Quote #38 (permalink)