antekboodzik - 3-9-2012 at 12:43 AM
Hi,
From time to time I see some wooden clamps, bookbinder's presses etc operated with wooden "screws". They are allways well crafted, and I like them
much, they are lightweight, and have natural and even decorative apperance.
So next step would be to try to make something at my own, for example a simple C-clamp with wooden screw. I realize that there are threading kits
available, but quite expensive for me. But what I found around me, there is a small "insert" for wood, with metric thread inside and another bigger
outside. I think after working it a little with files it should act like a professional threading tap.
But what to do then? Have You ever tried to do something like that? Write here your oppinions, please 
jdowning - 3-9-2012 at 07:54 AM
Cutting threads in wood by hand is the same procedure as cutting threads in metal except that metal threads are usually finer than those necessary for
wood - wood being weaker and less uniform than metal.
So to cut wood threads you need two tools - a tap (to cut the internal thread) and a matching die (to cut the external thread). The tap is made first
and then used to create the matching die. In the smaller diameters (12 mm to 25 mm) the tap is made of metal. In larger diameters a tap can be made of
wood fitted with an adjustable single tooth cutter.
For very large diameters, found on cider or wine presses, the threads were cut by hand with a chisel after first marking the thread spiral by winding
a piece of tape around the turned wooden blank.
I have cut threads using both methods - up to 2 inches (50mm) in diameter for a wooden bench vice.
The woods used for threading need to be hard and close grained. Cutting the threads is made easier by using dry soap or candle wax as a lubricant.
There is a very good article by Richard Starr in the Fine Woodworking magazine issue #6, Spring 1977 that I followed for cutting the large diameter
threads. The article can be viewed at
http://www.scribd.com/doc/45649726/Fine-Woodworking-Issue-6
However, a quick 'Google' search found lots of information about making the tools for thread cutting - both 'Home Made' and commercially available. So
that should be a good source of information to get you started rather than going into detail here.
Good luck!