Intro: Double Screw Wooden Vice (unfinished)
I got stuck with this project, due to the wooden threads not working properly - they get stuck, too. I have yet to manage to get them to work properly, but maybe someone else has a good idea about that, or can draw some inspiration from my mistakes, which is why I am publishing it unfinished. If that is not cool, please let me know.
All this is someone else's fault. Well, not really, but it starts with an instructable about a Treadle Lathe referencing the Woodwright's Shop. Not being from the US this was the first I heard about it, and I got a little hooked. Why a little, you ask? Well, with too little time to actually do any "proper" woodwork, but there was one episode that caught my attention. I admit I bought a wood thread cutter specially for making this, but I have plans to use it for other projects as well. Time will tell if I really do.
Anyway, I wanted to make such a vice for various reasons, not the least of which was that it appeared to be simple and easy enough to actually finish the project in a humane fashion.
Step 1: What You Need
- a board, roughly 4"/10cm wide, 40"/1m long
- a wooden rod, 1"/25mm in diameter, at least 20"/50cm long
- two pieces of wood for the screw knobs, about 2"x2"/5cmx5cm, at least as long as they are wide
- wood glue
- wood thread cutter, 1" thread
- drill press
- drill bit for centering (1-2mm)
- drill/forstner bit for 21mm holes (20mm will do, too)
- drill/forstner bit for 25mm holes (or slightly larger)
- some means to hold the various buggers down (possibly a vice)
Step 2: The Boards
I apologize for the lack of pictures in this step.
First, I cut two equally long pieces of board. I decided that half a meter would do.
Next I put them on top of each other and, taking care to keep the boards aligned, used a small drill and the drill press to mark the positions of the holes, which I determined, as you can see, by guessing.
Then, I took one board and used a forstner bit with 20mm diameter in order to create a core hole for the thread, and the other with diameter 25mm/1". The later I enlarged later in order to make it a through hole for the thread.
As the last part of this step, I used the thread cutter to cut threads into the two holes of the board with the 21mm/20mm core hole.
Step 3: The Thread
Making a threadded rod from wood is a great exercise if done right. Too bad I do not have pictures to illustrate it, but after I threadded the whole meter of rod, I felt parts of my arms that I did not know I had, for days.
Anyway, I used two pieces of about 25cm/10" length. I threadded the rest just because I could or thought I did.
A word on the thread cutter, in the forementioned episode of the Woodwright's Shop illustrates how to use them properly. They are not cheap, but like I said, I think of them as an investment on future weird stuff.
Step 4: Making the Screws - Success
In know that the more elegant way to achieve what I want to do in this step would be to take a larger piece of wood, put it in a lathe and turn it down to make the thread and leave a part standing to act as handle.
I do not own a lathe, and I did not want to "waste" the wood that would be turned off a larger piece if I did.
What I did was cutting two pieces from a slat, glued them together and used the drill press to drill a (slightly larger than) 20mm hole through them. Then I cut the thread, applied a decent amount of glue to the matching lwngth of the thread and screwed the knob on (I was half expecting Roy Underhill to emerge from under my work bench in order to lecture me on the proper use and dosage of wood glue...)
Anyway, I let it dry and (in my case) cut off the threadded rot at the appropriate length afterwards.
I did it twice, for (hopefully) obvious reasons.
Step 5: Making the Screws - Failure
For your viewing pleasure, here's my first attempt at making a handle/knob. I took a larger rod, cut off a piece of about 8cm/3" length, drilled the core hole and tried to gut a thread in it. I cannot say why exactly it did not work, but the thread cutter ate into the wood (which I guess was too soft).
Step 6: Bringing It All Together - or Not
In theory, the assembly should be the easy part. Put a screw each through the holes in the board with the through-holes, then screw them into the threadded holes of the other. Well, it is certainly easier written than done.
The problem I encountered was this - I could not screw the wooden threadded rod into the wooden "nut". It would go in for a few turns and then get stuck, going slow to begin with. Also, it was not easy to get it out again afterwards without damaging something. Here's what I tried:
- widen the inner diameter of the throug-hole, i.e. running a file over the thread's crest. No effect.
- the same as above with the threadded rod using sandpaper. No effect.
- (this I got from a web search) soaking the rod in water for a good while so the wood swells up slightly, then cut it again. This process did indeed remove some additional material. After letting it dry, it still would not go through as well as I had hoped, but it's an improvement.
- the same process as above used on the through-hole, though I got the distinct feeling that the board used was already wet, at least slightly.