How to Make a Wooden Nut General Woodworking
Occasionally, I get a little overwhelmed by all of the things that I could be doing and, as a result, don’t get anything done at all. Standing in the workshop trying to decide whether I should do a website project, a video project, or just do some general work around the shop to better organize the space, nearly an hour passes and I’ve accomplished nothing.
Poking around I found the worm gear from that project and thought it would be interesting to make the jig I talked about in this blog entry. At least it would be doing something that is potentially productive, and I would find out if the idea was actually a viable way to make a wooden nut.
Since I wasn’t 100% sure this would work, more of an experiment than an actual project, I used some old, scrap 3/4″ plywood to make the parts. This first, and arguably the most important part is the clamping collar that will hold the router in the jig. It is about 4″ square, with a saw kerf cut part of the way to the centre. I drew a circle using my compact compass that equals the diameter of the router body:
The kerf makes it so that the band saw can be used to cut out the circle:
Fine tuning the fit with the spindle sander.
The kerf cut serves another purpose: it provides space for the collar to clamp around the router. To tighten it, a 1/4″ bolt goes through the edge, and here I’m drilling the hole for it:
The collar is notched for the head of the bolt and the bolt is glued in on that side, to prevent it from turning.
The jig itself rocks on two pivot points, and I’ve marked those on a piece of maple with my compass:
The pivots are screwed to the sides. This probably looks pretty rough, but like I said, more of a prototype than a finished project. I added three more layers of plywood to the clamping collar to get the geometry right and still had to do some more adjusting after. One conclusion I’ve drawn from this is that it is too bulky and should be trimmed down quite a bit.
The rest of the jig is fairly straightforward. Just a plywood base and sides, with the sides notched for the pivots. The work holder at the centre is as detailed in the blog entry, with the only tricky part locating it accurately:
As shown above, there’s a one quarter nut piece in the work holder (the screw holds it in place during the cut) that has been routed to the correct depth and angle. It took a lot of trial and error to get the work holder placed correctly, and I had to make several adjustments before it would cut the part to the right size and depth. That was the most tedious part of the build, and the lesson learned was to make the work holder a bit bigger and mounted with bolts in slots, so that small adjustments can be made quickly and easily.
Here are a pair of correctly cut quarter nut pieces:
With them held on the worm gear / screw, it’s easy to see how well they mesh.
The first step to putting the nut together is to glue up pairs:
After the glue has dried, the pairs are glued together to form the basic nut.
Originally, I was going to stop here, but thought it would be better to add another layer to make one more complete thread:
I just glued four more individual quarter pieces on. Six layers, three complete threads.
While the glue was drying on the nut, I took the time to convert the worm gear to a big wooden bolt by adding a hex head.
While it was not strictly necessary, it certainly looks better for the video.
When the glue dried on the nut, I trimmed off the excess on both sides to flatten it, then glued on pieces of plywood to reinforce it. The holes drilled in the plywood ends are just slightly bigger than the diameter of the wooden bolt:
I made a short video of the action:
At some time in the future, I may make a final version of this jig, as well as a final version of the thread cutting machine. One of the long term uses for these machines is to produce a vise made completely from wood.
This next method is one I used before on the wooden c-clamp project, and that’s to actually carve out the threads by hand using a chisel.
The first step was to cut the blank for the nut in half, then draw a circle that is smaller than the threaded dowel diameter by the same amount as the thread depth. For example, I cut the threads into a 2″ dowel about 1/4″ deep, so the hole through the blank needs to be a bit more than 1-1/2″ diameter. The “bit more” gives the nut some slack, so that it will work freely. I then used the threaded dowel to mark the threads on the blanks, making sure the thread angle was right and that they lined up correctly. I used a 1/4″ chisel to cut each of the thread grooves around each half:
This really didn’t take much time and the results don’t have to be perfect, or look pretty.
When the threads are deep enough, the two halves will close tightly together and the threaded dowel should turn freely:
I glued the two halves together, let them dry for about an hour and then cut the nut out to look like a nut:
It’s likely that I will never use this for anything, but it was an interesting demonstration on how easily it can be done. I used spruce for the nut to make cutting it easier, but using hardwood shouldn’t take that much longer with a sharp chisel. Also, a Dremel tool could be handy to help cut out or clean up the treads, and that would speed things up.
The next method was one I had tried before as well. I started by clamping the two blank parts together and drilling a 2-1/8″ hole through:
The threaded dowel is 2″, so I thought it would be a good idea to make the hole through the blanks just a bit bigger.
Next I waxed and lubricated the threads so that the auto body filler would not stick. The filler was mixed up and spread into the nut halves:
The nut halves were then clamped together around the threaded dowel. The idea is for the filler to fill up the threads and after it has set, I can unscrew it:
Unfortunately, things didn’t quite work out that way!:
I could not get it to turn at all and eventually just smashed it off:
Lesson learned on that one. Along with how difficult it was to get off, there is also the question of how strong the body filler threads would be, and how well they’d stand up to constant use.
In the end, I’ve concluded the the best way to make a one-off nut is to do as shown above, cut it by hand using a chisel.
I made a video of the build: