markharrison
20th September 2005, 11:38 PM
I am chasing some wooden threads for making a work bench. Thinking around inch and a half diameter for the threads. Is this a suitable diameter for vice threads?
1 1/2" is big enough. To save you the trouble of hunting down several other "threads" on this topic, here is the condensed version of my previous efforts plus some other contributors...
There are commercially available taps and dies to make wooden threads up to 1 1/2" in diameter at 6 threads per inch (TPI). You can buy these from Carbatec, Timbecon, Mik and just about everyone else.
You can occasionally find old larger taps and dies through dealers and ebay though I haven't been lucky in my hunt so far.
There is also a company in the US called Beall Tool (http://www.bealltool.com/) that has a jig to cut the male thread with a router bit. Again the maximum size they make is 1 1/2" diameter at 6 TPI but I'm told that the results are very clean.
Another source of thread cutting tools is at Fine-Tools (http://www.fine-tools.com/gewind.htm) but be prepared for serious sticker shock at the prices for the larger sizes. Those prices are in Euros!!!!!
You can also buy wooden threaded parts ready made from the US in the larger sizes for very reasonable prices, especially when compared to the tools from Fine-Tools! The contact is Howard Card of Crystal Creek Mills, PO Box 41 DeWitt, NY 13214. Email at (if still correct)
[email protected]. His parts were used by Mike Dunbar in a Fine Woodworking article on building his workbench. I haven't tried them myself but I've heard good reports from other users at Woodcentral.
See this thread also (http://www.woodworkforums.ubeaut.com.au/showthread.php?t=8513&highlight=router+cut+thread+jig) for more information on creating a jig to cut male threads with a router.
Note though, it glosses over the difficult part. Making the die. Here’s one untested idea I postulated in another thread to make a die and thread box using an existing large bolt. Here is the sequence:<o =""></o>
Cut slots in bolt to form tap.<o =""></o>
Clean up threads and sharpen. You now have a bottoming tap.<o =""></o>
Optional, harden and temper bolt.
Using matching nut embedded in a wood holder to guide the tap (remember this is a bottoming tap) cut a wooden thread in thread box to form die.<o =""></o>
Using a V cutter (you can buy spares for thread boxes from Timbecon I know for sure or you can make your own) make the thread box. Or, use the router method outlined above to cut the male threads.<o =""></o>
You will need to see how a thread box is constructed to get this last part. Unfortunately being sans digital camera I am unable to offer an example but perhaps someone else here can provide photos. However, I don't see that as being particularly difficult as these are fairly simple devices. The hard part has always been making the tap.
You can buy bolts in the larger sizes (I've seen 50mm 2 TPI in an online catalogue here in Australia but I can't lay my hands on it at the moment, brain flameout). I've no idea what the cost would be but I can't imagine that they would be excessively expensive. Certainly a lot less than 907 Euros!
Cutting the slots for the tap need not be too precise. I think a jig with an angle grinder could cut an acceptable slot. I wouldn't try this free hand but I find an angle grinder to be a particularly scary tool. YMMV