On Sun, 3 Apr 2005 08:11:31 -0700, "Roger Shoaf"
wrote:


"Larry Jaques" wrote in message
.. .
You will not be able to cut threads with your router.

Tell Beall that. They've been selling a tool for that for years.
www.bealltool.com/ (though it doesn't appear to be up right now)


You mean this:
http://www.bealltool.com/threader.htm

It does appear that Beall uses taps for internal threads. I can
imagine a router-based tool or jig that could cut internal threads,
but it would take some machining. The basic idea would be that the
router bit would have the correct shape, and the router axis would be
offset and canted at the proper helix angle. The jig would then
advance the workpiece axially as it is rotated, thus cutting the
internal thread to the correct pitch. I expect this would cut
considerably better threads in wood than a tap could do because the
cutter would be running at high speed, removing only a bit of wood
per cut. Sounds like an interesting project.