Manual thread rollers designed for rolling threads on spokes are a
great idea.  The ISO standard for bicycle threads is 56 threads per
inch, regardless of the spoke gage.  This family of thread rollers
produce a very fine thread, which may not be suitable for use with
leather nuts or wood.  The cost to have custom rolling dies made by
Fette or Cleveland Die would be prohibitive.

One feature found in the industrial thread rolling machines is
that each of the thread roll dies are interconnected by gears,
consequently the thread pattern of each die roll follows the exact
same path, producing a clean sharp thread.  The units described
previously don't seem to have this feature, but they may work fine
on steel spokes.

Thread rolling is a common screw machine operation which might be
adaptable to a metal lathe.  The tooling designed for screw machines
is similar to the geared type described previously, using a precisely
positioned setup with a special tool holder and thread rolling dies.
This technique is not commonly used for threading wire or other
non-rigid materials.

A bump roll (single roller) is sometimes used when only a few parts
are produced.  This uses one thread roll die positioned similar to
a knurl and requires a follow rest opposite the rolling die.

The thread roll will not self-feed, and must feed at the same feed
rate as the thread count, similar to the common method of a single
point tool cutting a thread.  Because of the pressures involved to
imprint the thread, the follow rest tends to distort the thread
pattern when used for small diameter material with fine threads.

Unless you have plenty of extra time and/or surplus of cash (Laukhuff
makes a very nice little machine -- expensive!), the best choices
seem to be:

- Use a standard threading die.  In this application a lathe-mounted
die chaser works better than a fixed size threading die.  Cutters are
available for most thread sizes, and the thread OD can be adjusted
to a much larger degree than the common split die.  New die chasers
can be expensive, but can often be found used for $200 to $300.

- Have the threads rolled by a thread rolling job shop.

- Look for another standard hardware item which can be adapted.

I have been looking for a simple method to roll threads for a number
of years; short of spending several thousand dollars or an equal amount
in time fabricating a substitute, there doesn't seem to be a simple
solution.

Dana Johnson