Originally Posted by
HillRider
Well, good bicycle spokes have rolled threads and good spoke threaders (like the Phil Wood threader) do roll the threads. There are less expensive threaders that cut threads with a standard-type threading die which do work but the spokes aren't as durable.
There's a fundemental difference between cut and rolled threads.
Sketch
With cut threads the full profile of the thread is cut into the blank, which is the diameter of the crest of the thread, and the extra metal is removed.
With rolled threads, no metal is removed. Instead you start with a blank whose diameter is halfway between the outside and inner tread diameter, and flow metal from the troughs to form the peaks.
1.8mm and 2mm spoke threads are rolled, and the threads have a larger diameter than the spoke wire. While you can cut the same threads into the wire, you would only have the troughs and the crests would be missing. There's no difference in strength of the spoke since the thread depth is the same, but the holding power of the nipple would be severely compromised. You could cut a smaller thread but then you'd never find nipples to fit.