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 it's 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.
Secondly I went and looked at my wheels. It would seem that the need for seating the elbows is rare to the point of obsolete with today's wheel components. Even the lighter weight hubs I have still exhibit thick enough flanges that there is absolutely no need for setting the elbow or spoke head. With older steel hub shells exhibiting much thinner flanges it may have been more relevant. But even in those situations I'd rather use spoke washers.
Which brings me to my next point. Spoke tension should take care of any spoke path issues in due time. In fact a proper stress relief should also set the spoke paths pretty much immediately. I find it extremely unlikely that the spoke head would be able to spring out against 1200 newtons of DS tension and 700 newtons of NDS tension. We're speaking about 2mm steel wire that you can put permanent bends to with your fingertips. When we tension the wheel, the spokes experience elastic deformation. It just simply isn't possible that you'd have a floating piece of spoke flexing against the pull of the spoke while you're still having the spoke stretch for sometimes more than 1mm or so (for very long at least)
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.
You have built how many wheels? I have built hundreds. The people I have worked with have built hundreds, and the people they learned from have built hundreds or thousands of wheels. All of those people use the same basic set of techniques on all thoroughly modern equipment - not steel hubs. All of us agree on these basic principles, as will any wheelbuilder you care to find. And all of us have seen the kind of elbow failures being discussed on equally modern equipment, and have SOLVED those issues with the techniques discussed. Because machine built wheels commonly have a poor spoke to flange contact, and we have seen that many, many times.
There aren't any "thin flanges" and spoke head washers in modern wheels. All of these dimensions were worked out for alloy hubs decades ago.
I, as a representative of the professional wheel building industry, am trying to relay to amateurs how this stuff works and why. I am extending the courtesy of sharing those things the best I can in the face of a lot of objections that are fun to talk about, but are basically the theories of people with little to no real experience or education.
So this situation is analogous to going to your doctor and arguing about the power of crystals to cure cancer. I don't care what you think you've learned building a handful of wheels, or by reading a metal chart. The basic facts remain the same, and you are wrong. Any pro builder that says that spoke elbow seating is unnecessary would be a fraud - but basically such a professional doesn't exist. Everybody paid to build wheels professionally does it and teaches it because it works.
Or you can take the word of the guy who has broken tons of elbows not setting them, and is therefore convinced elbows are delicate and every wheel needs 2.3mm elbows. Even though we know good wheels don't break elbows. Even though being the "go to" guy at a coop is like being the most handsome carnival worker.