- 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.
- 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.
- A wood shop
- 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.
|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.
|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.
|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 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
|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.