Thanks Nic, thanks all.
This is turning out to be very informative for me, I appreciate it.

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"Gimondi è un eroe umano, che viene sconfitto ma che continua la sua corsa fino a tornare a vincere." - Enrico Ruggeri

The thread size is markedly more important than thread length. Thread surface area increases as diameter increases, but ~90% of load is in the first 3 threads.

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Success is how far you you bounce back up after being knocked down

Interesting sidebar from http://www.cyclingnews.com/teamtech04.php?id=tech/2004/probikes/panaria_battaglin

re: Graeme Browne's bike

"...Inside the "cockpit", it's really no surprise to see Deda's Newton 31.8mm oversize bar and the slightly stronger Deda Magic stem on board. Sprinters need all the stiffness they can get, and with a combined weight of 397 grams, it's one super-stiff, very lightweight combination for the team pursuit world champion...."


"Deda's Magic 31.7 stem - a little heavier than the Deda Newton, but a tad stiffer."

Interesting also that the Magic has the 2-bolt clamp.

_________________
"Gimondi è un eroe umano, che viene sconfitto ma che continua la sua corsa fino a tornare a vincere." - Enrico Ruggeri

3bold

Florian is right: I took the stem in to LBS yesterday, and they mentioned that the clamp on the older Deda Newton was a "semi-recall" (i.e. unpublicized) item, because of many similar cracking issues, due to flawed design.
The clamp has apparently been redesigned, and your LBS will replace the clamp for free.

_________________
"Gimondi è un eroe umano, che viene sconfitto ma che continua la sua corsa fino a tornare a vincere." - Enrico Ruggeri