Self-extracting crank bolt failure

I got a pair of self-extractors assembled from dust cap and
crank bolt separately by Harris. On attempting extraction,
the cap unscrewed a few degrees so I stopped to investigate.
I removed the bolt and attempted to run it in the cap.

What I noted was that the bearing surface was on the outer
rim of the bolt flange, not the inner chamfer of its socket
head. So I set up my grinder and took off 0.1 mm in
rec.crafts.metalworking under Truing Stone or something.
Then I put the bolt in the drill press and used a very fine
file to polish the flange.

Now the extractor bears in the center and my cranks are
beautiful. I even put the caps in so the holes line up, with
blue nut lock.

You see, it's a question of moment and torque.....

Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

My physics project at NVCC: Google Groups, then
"dgoncz" and some of: ultracapacitor bicycle
fluorescent flywheel inverter

4-1-9 Fraud
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"MGS" <[email hidden](remove the remove)> wrote in message
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Quoted message said:

On extracting the drive side crank on a pair of FSA
compact cranks, the

self

Quoted message said:

extracting bolt stripped and pulled out of the crank arm.

The end result was damage to both the self-extracting
cover of the bolt

and

Quoted message said:

the crank arm.

My LBS was kind enough to realize that the extracting bolt
either was defective, or the system is defective. In
either case, they replace the crank arm and I am now using
the standard crank extractor.

Has anyone else had problems with these self-
extracting bolts

Yes, just the same, except that my crank was undamaged, once
I'd picked the stripped bolt cover threads out of the crank
threads. I put it down to the fancy anodizing having made
the cover more brittle or something, and got a different
brand (Zero) in plain silver, which have been OK since.