Lugged joint failure

[thruthefence]

Can someone knowledgeable comment on the photos posted on this link?

http://bbs.homeshopmachinist.net/showthread.php?t=46317

 

[ctopher]

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

 

[MikeHalloran]

Nice pictures.

Are those bubbles in the filler metal?




Mike Halloran
Pembroke Pines, FL, USA

 

[thruthefence]

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.

 

[ctopher]

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

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

 

[DLite30]

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.

 

[chicopee]

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

 

[ACtrafficengr]

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/