Originally Posted by
elcruxio
A few thoughts.
Firstly AISI 304 or 18/8 or EN 1.4301 is a decent spring steel. One of the common uses for said steel is actually springs. One big reason why it isn't used for bicycle frames is its price. Stainless steel in general is pretty expensive and even though 304 is fairly common stuff, it's still around the double the price of AISI 4130.
He’s got it in his head that stainless steel is some how “soft” or “weak” as compared to mild steel. It’s based on a very old myth that says the carbon steel spokes are somehow better material for spokes because…reasons.
Here’s an article on stainless steel as spring material.
What I suspect is happening is along the lines cyccocommute wrote earlier. If I refine a bit, when a wheel is built and the component selection is done badly (ie. the flanges are thin and spoke elbows are long and no spoke washers are used) and no stress relief is done or it is done to too low of a degree, the elbows may remain "floating" away from the hub flange. Tension will however, in time, pull them into submission against the flange. Depending on how far outside the elbows are, the subsequent bending against the flange would effectively lengthen the spoke which can drastically drop the spoke tensions of the wheel, which would then logically lead to spoke failures if not addressed.
So to conclude, I believe that these days spoke head or elbow setting is necessary only when there's some inherent incompatibility with the spokes and hub. However the same effect could be achieved with spoke washers. With most modern aluminum hubs and DT Swiss spokes (I've ever only built with DT Swiss) spoke head or elbow setting simply isn't necessary since the spokes adopt a perfect path against the flange when the wheel is properly tensioned.
I do it because it reduces possible variances in the spoke tension over time which lead to the problems you outlined. It can also be part of the stress relieving process. Side bending of the hub, i.e. setting it on the floor and bending the hub down, is part of bending the spokes to the hub. Prebending them by forming the spoke to the hub does this before tension is even applied. I haven’t side bent a wheel ever during a build partly because Hjertberg has said
not to do it. Even in the article that taught me how to build wheels written 40 years ago, he was advising against side bending
If spokes are prevented from winding up, potentially dangerous methods of releasing stress are unnecessary. These include bouncing the wheel on the floor, or laying it on its side, grabbing the rim at 3 and 9 o'clock, and vigorously pushing down. This is a popular technique, but it's best reserved for straightening bent rims, not building new ones. Surviving a massive side load might be a sign of strength, but it might also weaken or ruin a wheel.