Making a Tap and Nut

In the woodworking community there seems to be an explosion of obsessed woodworkers building workbenches, yes I fall into that category of being a obsessed woodworker too, but I have no bench.  Recently I've been planning on making a workbench, but it costs a lot. I figured that I might not be the only one with a thin pocket book, so I thought I would share some cost saving techniques when building your own bench.  One way to save money is by making your own screws for a vise on your work bench. In this tutorial I show how to make a tap, which will be used to make a nut. The nut will be used in my next tutorial to show how to cut the threads for the wooden screws.


  Material list

• One 2" hard wood dowel 18" to 24" long.
• Two 8/4 hard wood blocks 4" by 12"
• Two pieces of 4/4 2" by 6"
• One piece of 1/8" or 1/4" tool steel 1/2" wide by 2" long.
• One piece of sheet metal the same thickness as the kerf                  your handsaw makes 1 1/2" wide by 12" long.
• Glue.
• Clear tape.
• Graft paper. 
• Optional 8/4 hard wood 3"by 3"
• Optional 3" circle of sheet metal at kerf thickness.  
• Optional Four wood screws 1 1/2" long.

Tools needed

• A wood shop 
• Pencil.
• Ruler.
• Square.
• Couple claps..
• 2" forstner bit.
• 1/8" drill bit.
• 1/8" chisel.
• Hand saw.
• Tin snips.
• Metal file. 
• Drill, preferably drill press.
• Band saw.
• Table saw.

In this tutorial I used a two inch poplar dowel
 and two birch blocks that are 2" thick,
 about 4" tall and 12" long.
I'm using  poplar and birch to demonstrate
 how to make the tap and nut. The best woods to use
 however is a hard dense close grain wood, like
 hard maple or a fruit wood.

To start you will need to pick the face side on both
of the two birch blocks. Now find the center on each face
side and mark them. You will need to repeat this
 process for the top and bottom of the blocks.

I then wrap a strip of graft paper around
the dowel to measure the circumference. 

I transferred the measurement
 on to a full length of graft paper.

On the graft paper I laid out
my lines so that I would have two teeth per inch.
To make right handed threads I start from the
top left at zero and draw a diagonal line to the bottom a half an inch over. I repeated this every half an inch. If I had drawn the lines
slanted the other way it would have made them left handed threads.

Trim up the graft paper to the desired length.
 The longer the length the thicker the
 nut you will be able to tap. I saved
 a piece of the cut off graft paper to help with the
 layout on one of the birch blocks.

Using clear tape, tape the paper to the dowel. Make sure to leave a little of the dowel exposed at the front of the tap.
 This is so that when you tape the ends the tape will be half on the paper and half on the dowel.This will secure the paper when cutting close to the ends.

The lines on the graft should
 line up with each other to make a spiral. Before
 cutting the spiral I grab One of the birch blocks.

I find the center mark on the top that I marked earlier. I then take the piece of graft paper that is marked
with the same angle as on the tap.

Mark the center diagonal line of the
 graft paper on to the left and right side
  of the block.

Center your paper with the center mark
 that is on the top of the block.

I connect the two marks,
drawing a line across the top. 

On the front face measure up one quarter
 the thickness of your dowel (for a
 two inch dowel measure up a half an inch.)
 Then transfer the mark
to both ends of the block.

Then extend the marks from the front
 and top of the block, across and
down the sides of the block. This shows
where to cut and how deep to cut,
  for installing the strip of metal.

After all the layout marks have been made
on the one block. I drill a 2" hole through the
center of both blocks.

I grab the block that has the diagonal
 layout line on top and cut the top line to
intersect with the horizontal layout line
that is on the end of the block. I then
install the sheet metal into the kerf.
Depending on the depth of the cut line
 you may need to file the metal to fit
 around the center of the tap. when the tap
 is twisted in, the metal will slip into the
 spiral, pulling the tap forward. 

 I put the dowel through the holes
 in both blocks, to secure the dowel
 while cutting the spiral.
I only cut a half inch deep. 

This is after the iron is cut to size, shaped
and tempered. I cut a mortise in the dowel to
 house the iron. This was easily done
 with an 1/8in drill and a 1/8in
chisel. 

The iron is 1/2" wide and 2" long. I cut it from an old plane iron I had laying around the shop.  I heated the iron up with a small torch until it was red hot then slowly let it cool to make it more ductile. I couldn't shape it until after it was annealed.  I filed a 45 degree angle on both corners, so the point is a 90 degree angle. I squared the edges of the iron to its face on a couple sharpening stones. I turned the torch back on and slowly started to heat the iron. The iron starts to change colors the hotter it gets. The colors are easy to see on the polished surface of the iron. Its important to make sure not to heat just the very tip. I kept the heat towards the back of the iron and slowly watch as the colors crept up to the tip. The iron changed from a yellow to a brownish yellow color, to purple then blue. The blue is a little to hot, so as soon as you see the purple reach the tip dunk it in a cold cup of water (this will make the iron hard again and keep its edges sharp longer.)

I ended up removing some of the material
between the two pencil marks,
with a small gouge, to allow
 a place for shavings to collect.

The iron is kept in with a hard maple
 wedge that I cut flush
with the surface of the tap.

The next few steps show an alternative way to installing the metal piece that helps pull the tap through the jig. The above process maybe a little easier and works just fine. I cut a piece of 8/4 into a 3" circle, with a jig on the band saw to make it perfectly round. I do the same steps as above, laying out on graft paper two teeth per inch for a three inch circle. I tape the paper on the circle and cut the spiral with a hand saw just a hair deeper than an inch, making sure not to cut all the way to the end of the spiral. I leave wood on both ends, this will keep the spiral together when drilling the 2" hole through the center. I then mark the center of the circle and drill a two inch hole. I saw down one side of the circle and the spiral separates into two halves. I lined up the hole on one half with the hole in the birch block and glue it together. I made a 3" metal circle and cut a 1 1/2" hole in the center of it. I then cut through one side of the circle. Now I sandwich the metal between the two spiral halves, drill four holes through the sandwich and screw it into place. This will give me a 1/4" metal spiral that the tap can twist into.

I rounded the sharp corners of the metal
 to keep it from snagging the inside
 walls of the spiral. 

This way gives one complete turn with
a metal thread. Using this type of thread
 allows less wear and tear on the tap,
 because it gives equal
pressure around the taps spiral.

I added blocks to the front to give a space
for the cutter go into when exiting
the nut .

Here I clamp the other birch block
 onto the jig and insert the tap.

I slowly raise the cutter after every other
pass, if  I raised it to fast I r could risk ruining
the threads or possibly breaking the tap.

I take my time twisting the tap through.
slow and steady seems to make
 the best results.

Do not worry if there is a little tear out
in the end grain of the nut. To help with tear out I
remove the tap before the last couple passes
and stabilized the end grain
with some C.A. glue. 

Finished product, This will become the jig
for making the threads for the screws.