Sunday, July 29, 2012

Screw Boxes and Wooden Threads

Finished Product

Threaded wooden screws can be incorporated into a multitude of tasks and tools. In an earlier post I showed a plow plane I constructed utilizing wooden screws for the fence adjustment so I thought it would be an interesting post to explain how easy they are to make.

First a screw box and tap is needed. The one shown here I ordered from Woodcraft several years ago. I also have a router driven set from Beall Tool that makes outstanding threads.  Next suitable wood is needed. Use fine grain straight stock. I’ve used hickory, maple, yellow birch, and even cotton wood which I don’t recommend. The best wood by far is persimmon and it’s the wood I used for this post.

Rough Blank 
The screw I made in this post is ½ inch diameter. I planed the wood down to just a bit above a ½ inch and cut the wood into the shape of a ‘T’. Next I carved the lower part of the T into a shaft. This really isn’t hard. You could use a lathe to turn out rough blanks and I do for larger screws, but for the small stuff this is the most efficient way. Don’t bother carving the head of the screw yet. If your threading doesn’t turn out you haven’t wasted any work.

 I checked that the diameter of the shaft is correct by testing its fit through the guide block on top of the screw box. Some wood can be made to thread easier with a lubricant like mineral spirits. The persimmon I used didn’t need it.    

Guide Block On
The first threading I did was with the guide block on. With this screw being short I needed to back the screw out and remove the guide block so I could cut threads closer to the head. It’s also a good idea to make your threads longer than you need, you can cut the excess off later.

Next all that’s needed is to shape the head. I will cover tapping the screw hole in a following post that will detail how I make my marking gauges. 

Guide Block Off


Crystal Mary said...

Good onya, and well done. Blessings from Oz.

Ralph J Boumenot said...

It never occured to me to take that block off to thread closer to the head. What's obvious to someone isn't so to someone else. Great tip.

Gorges Smythe said...

Good post. Hope you don't mind that I linked it.