Originally Posted by
FBinNY
The fact that you've never seen failed brass nipples isn't evidence that they don't fail. It's only evidence of your lack of experience.
As I pointed out in an earlier post, nipple failure when spokes end short of the rim is a well documented phenomenon. No new research is needed since it was researched extensively and exhaustively. May I suggest searching for the supporting research that the CPSC used in creating their first bicycle standards over 40 years ago. That would be a place to start if you care to learn, or you can base your conclusions entirely on your personal experience.
The nipple may fail due to corrosion, undesized wall thickness and/or inferior metallurlogy (cheap no-name junk import), or damage by a spoke wrench! Cut a DT Swiss brass nipple in half and measure the effective cross-section area using an optical comparator. Now use basic strength of materials to calculate the allowable safe load.
There have been a tremendous advance in material science and manufacturing technique over the last 40 years. Do you still rely on engine design protocol from the 70s to build a modern direct-injection gasoline engine with 12:1 compression ratio?
Thirteen years ago, I helped a friend build a wheel with spokes that were at least 2.5 mm short at the rear (both side) using straight DT 2.0 mm spokes. The wheel held up like a champ even after 4 years of use (before it was sold to his friend).