Lugged joint failure

• Feb 6, 2011

• #2

ctopher

Mechanical

Jan 9, 2003

17,509

Looks like minimal braze and fatigue failure. A 22 year old steel bike, could happen.
What do you think happened?

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

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• Feb 6, 2011

• #3

MikeHalloran

Mechanical

Aug 29, 2003

14,450

Nice pictures.

Are those bubbles in the filler metal?




Mike Halloran
Pembroke Pines, FL, USA

 

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• Feb 6, 2011

• Thread starter
• #4

thruthefence

Aerospace

May 11, 2005

733

It wasn't my bike, I'm just a lurker on the machine shop site, the poster, Frank Ford, is a Luthier, and no fool around machine tools. Apparently the bike belonged to his business partner, and had a sudden failure after 20 years on the road. I'm mostly just curious about the process, which apparently is well developed, and understood in the bike building world.

 

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• Feb 6, 2011

• #5

ctopher

Mechanical

Jan 9, 2003

17,509

Has there been any testing on the bike to see why it failed?

Chris
SolidWorks 10 SP4.0
ctopher's home
SolidWorks Legion

 

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• Mar 18, 2011

• #6

DLite30

Mechanical

Jan 7, 2010

245

Judging by the length of the head tube, the guy had to be pretty tall (read heavy). And I'm the frame saw a few decent sized cracks and potholes. So I'd say the bond just failed due to fatigue. Not suprising really.

 

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• Jul 31, 2011

• #7

chicopee

Mechanical

Feb 15, 2003

6,199

If this bicycle was made in China, then no wonder.

 

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• Aug 1, 2011

• #8

ACtrafficengr

Civil/Environmental

Jan 5, 2002

1,641

DLite: Perhaps it's not surprising in retrospect, but I bet it was a surprise to the rider when it happened!

Maybe the tyranny of Murphy is the penalty for hubris. -

http://xkcd.com/319/

 

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