On 12/11/2017 8:23 PM, John B. wrote:


Hey! After the saga about building small wheels and the spokes that
didn't tighten, you never did divulge your secrets of how to built
small wheels with long spokes :-)

It was a very frustrating process. One of my best friends used to own a
bike shop. (BTW, I have other friends who used to own bike shops.
Apparently it's a tough way to make a living.) Anyway, he has a Hozan
spoke threader. Its dies roll the threads onto spokes.

So I borrowed it. (It's still in my basement.) Using extra spokes I had,
I experimenting with extending spoke threads a few millimeters, which I
figured was all I needed. But I failed again and again, probably many
more than 20 tries. I played endlessly with the depth adjustment of the
threads. I tried cutting spokes short and starting on the unthreaded
portion of the spokes. What I found time after time was a nipple would
thread on only about 6 to 8 mm, then bind. I tried several types of
nipples, and starting from either end of the nipples. No dice.

Looking with super-close-up goggles, then with a small microscope, it
seemed that the thread form was not symmetrical, not truly perpendicular
to the axis of the spoke. The threads sort of leaned one way, so to
speak - but I don't really know if that was the problem. My friend lent
me another head for the tool but it did no better. I did trials cranking
the thread roller by hand, and many more using an electric drill to do
the trials more rapidly. I lubricated using ordinary oil, then cutting
fluid. Nothing worked.

So I gave up on the proper solution, and went with a kludge. I
counterbored the original nipples about 2 mm, and also slid thin washers
onto the nipples for a belt and suspenders approach. The wheel tensioned
up fine, straight and true. Since the spoke ends are essentially even
with the "top" surface of the nipple, the original error was probably no
more than a millimeter, whatever caused it. I still suspect a slightly
undersized rim.

--
- Frank Krygowski