On 29 Sep, 22:34, jay wrote:
On Sep 29, 1:12*pm, Jobst Brandt wrote:



Frank Krygowski wrote:
When I took the wheel off, my heart skipped a beat. *Without much
effort, this is the result:

*http://www.bitrealm.com/misc/fork/p1000783.jpg
*http://www.bitrealm.com/misc/fork/p1000784.jpg
*http://www.bitrealm.com/misc/fork/p1000785.jpg

It was hanging by no more than 2mm of steel. *I shudder when I
think of the roads I was about to go on, including one really bad
bump at the bottom. *I don't think it would have held together and
when you lose the front like this, it's going to be bad.
Lucky you caught it when you did. *Last year, our old custom tandem
let go of both blades simultaneously. *The warnings I got were
nowhere near as explicit as yours. *Fortunately, we were moving only
about 10 mph at the time.
In my case, the bike was built by Jim Bradford, formerly of the
Atlanta, Georgia area. *It was the last bike he built before getting
married and leaving on a honeymoon. *I suspect he slapped in
whatever fork blades he had lying around in order to get the job
done, because the wall thickness was roughly one-third of the proper
gage for Reynolds 531 tandem forks.
I wish I could offer advice on how to choose a competent and ethical
frame builder, but I can't.
BTW, I think you shouldn't have too much trouble finding a
replacement. *I was able to buy a replacement tandem fork from
Tandems Ltd in Alabama. *For a single bike I intend to build, just
last year I was able to buy a chromed Japanese fork from Citybikes
in Portland, Oregon.

*http://www.citybikes.coop/

This is a classic fork failure in which the lug interface between fork
blade and fork crown had not been feathered after brazing. *This
failure could be seen coming while "Cinelli" fork crowns that are
internally lugged, do not reveal their trend to failure until after
fracture. *However after failure they were obvious failure points.

Many joints between lugs and frame tubes may be shiny chrome but they
have discontinuous transitions that cause fracture as in this one.

Jobst Brandt- Hide quoted text -

- Show quoted text -

What is feathering?

JB flapping.