How-to Thread and Tap Large wooden Vise Screws and Nuts

[george wilson]

Our big German screw box had handles that made the whole thing about 18" long. That is a guesstimate since I haven't seen it for over 2 years. It did get tiresome turning it,though!! Saturating the wood with mineral oil did help,and did no harm to the wood.

I was thinking I could make a large tap. What I can't figure is how to make it available to everyone on a loaner basis. It would be a good amount of work to make a 2" tap,3 TPI.. The tool steel would cost money,and it would be fairly valuable. Even if a person paid a $200.00 security fee to borrow it,the tap would still be worth more than that. It is a service I would like to provide somehow,though.

I don't know if I want to get into threading everyone's screws,either. That could become a big job,and I am too creaky to want a lot of physical labor like twisting big taps.

[Matt Evans]

I made a screw box, then replaced the cutter with a a few electrons. Unfortunately, I don't have pictures of the setup before the addition of the router. So will have to build a new one to show ya'll.

The handle on my tap is 18" long. If youtake a big cut, you need every inch of that leverage, particularly on the end grain.

[robert dankert]

Great thread, thanks for posting!

[Lou Yelgin]

I picked up an old wooden vise bench screw at a flea market recently. The screw is in good shape and was a piece of woodworking history, so I could not resist. It is approximately 1 5/8" x 3 tpi. I showed it to a machinist friend who said it was a non-standard 200 year old thread, so it would not match anything on our modern thread charts.

I have thought about making a nut in two halves using carving tools. How would you recommend I make a nut for this screw?

Thank you for your advice.

Lou

[george wilson]

If you are pretty good,you could carve the nut in 2 halves. I have seen it done. I am wondering if there is some way you could build a box around the screw and cast a nut? You'd DEFINITELY have to VERY thoroughly grease the screw to avoid gluing it to an epoxy based material poured around it.

I don't see why a machinist can't cut 3 TPI. I frequently made screws on a metal lathe to fit existing nuts on benches in Williamsburg,using a router in the tool post to cut nice clean threads. Our screws were 3 tpi.. I did have a lathe that had a very comprehensive number of threads it could cut. I am retired now and don't have that lathe. Often machinists don't want to be bothered with special stuff like that,though.

[Karl Andersson]

In the Landis Workbench Book page 123 it shows an example of making a nut in two halves for an existing screw. If you don't have access to the book, it describes the process as: put blacking on the screw threads, close the nut halves against the blackened threads, open nut and carve away the blacking on the nut halves, repeat until nut is closed. It isn't obvious in the book's picture, but you'd want to use long rods/ bolts to connect the two nut halves or another method so they remain square to each other whenever you re-clamp them to the screw. You'd also want to keep the nut at 90 degrees to the shaft of the screw.

[Matt Evans]

If the weather turns nasty again today I might have time to do a really quick tutorial on this. If not It may be a few days, but I will try to get it done sooner than later.

Just a quick note though. . .blacking is great, but stains the wood. I have been using carbon copy paper for my transfers, and it works pretty well for the initial layout. After that, you tighten the nut and twist the screw. The "burnished" wood stands out perfectly, no other marking needed.