Picture of Wood Nut for a Wood Vice Screw
1.5 the screw.jpg
In the construction of my leg vice, by the grace of the cosmos I came into possession of this huge wood screw.  I estimate it to be about 100 years old; it looks like it's seen enough action to have earned a few purple hearts and a postgraduate degree.  But the requisite nut, that component needed to turn rotational force into amplified lateral force, was nowhere to be found.  I had the option of making the complimentary nut on a wood lathe, but I also have access to a CNC router.  I could machine a nut to precise dimensions and, if I'm careful, I can do it right the first time, wasting no wood.  
  "Pass me the calipers" I said.

 I make all my wood nuts at TechShop.
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Step 1: You Will Need

Picture of You Will Need
  • Calipers
  • 3D modeling program (I used Autodesk Inventor)
  • a CNC router (I used a ShopBot)
  • 1/8" router bit (ballnose)
  • 1/2" router bit (I don't care what shape, whatever makes you comfortable)
  • Wood glue
  • Basic woodworking tools

I have opted to use poplar wood for this project.  Though it is a bit softer than maple (the typical wood of choice for threaded parts) the  very coarse threads with a 2" diameter make for a robust shape that requires minimal edge-holding properties.  

Step 2: Taking the Dimensions of the Screw

Picture of Taking the Dimensions of the Screw
2.2 measuring the screw.jpg
Using calipers, carefully measure the height and width of the threading. These threads are triangular, making the dimension a simple function of height and width.  Here I focused on the most intact areas, as they have the truest dimensions and the nut must accommodate the widest part of the screw (and then some, but more on that later).    Next, measure the diameter of the screw, both inside and outside, and count the threads per inch.  These dimensions are constrained by each other, so theoretically knowing the width of the thread and the threads per inch will give you the diameter, or knowing the diameter and the width of the thread will give you the number of threads per inch.  But our world is not an ideal one, so take those measurements.
skyboy_psu1 year ago
Do you have the autodesk file for the threads saved and would you share it?
rimar20002 years ago
Impressive, congratulations.
cool, where did you get the wood screw?
Scotttland (author)  amandaghassaei2 years ago
The Pakistani black maket. Just kidding. eBay. Definitely not the Pakistani black market.