I made one of those, I used a 55 degree thread, 3.5 threads per inch.
turn the tap out of high speed steel, mill in three flutes. The tap
was so large I easily relieved it with a file, after blueing it.
After hardening, it was sharpened with a fine stone on a die grinder.
I cut very sharp threads in clear maple for the nuts useing beeswax as
a lubricant.
The screws were made with a router mounted in a metal lathe, I ground
some 55 degree cutters, I calculated thread depth, and cut the thread
one pass in slowest backgeared speed.
Dennis




On Fri, 17 Dec 2004 10:03:26 -0800, "Roger Shoaf"
wrote:


"bob" wrote in message
roups.com...
I want to make a wood screw for a vise(2in. dia). I have tried using
dried and green oak and 3 tpi. The threads for the nut cut very nicely
but the outside threads are a mess. Lots of chipping and tearing. Is it
the wood, the tool grind ,or me? I have also tried cherry and it was
worse than oak. My brother ground the tool for the inside threads and I
ground the tool for outside and am a relative clutz so I hope it is
just the grind.
Anyone with experience doing this?
Thanks,
Bob


Seems to me that using a wooden screw for a vise is something you would do
if metal were not available. The only time I have seen wooden threads is on
broom handles painting poles and that is the usual point of failure.