With the wooden thumbscrew finished I turned my
attention to constructing a much needed adjustable mortise gauge. The style I decided
on has two adjustable beams with a nail inset in each end to act as a scratch awl.
With this design I can adjust the width of the mortise as needed and I am only
limited by the length of the two beams. Another feature I feel is a must when
using a thumbscrew is the captive pad, it prevents the thumbscrew from marring
the beams.The wood for the gauge is from a white oak beam I salvaged from a barn that was built in 1867. It has a wonderful caramel color and is quite dense. I am very happy with this tool.
When tapping threads in a piece of wood the same
rules apply as making the screw. Use fine grained wood. Normally I would not
use oak, but as mentioned earlier this oak is very dense and hard. I’m guessing
it has to do with either the age or it could be that I counted 32 growth rings
in the small section that makes the head. This tree had to be well over a
hundred years when cut down in 1867.
The hole for the tap has to be straight and smaller
than the diameter of the screw. If you buy a threading kit it should tell you
what size drill bit to use. I just practice on scrap to make sure it’s the correct
diameter and tap that before using it on my project. With this oak I used my
post drill to make sure the hole was straight. Post drills are really more for
metal, but I don’t have a drill press so I used it. When I made my slitting gauge
I used an auger bit and just eyeballed the hole and got it straight. I think
that was more luck than skill.
I used linseed oil to lubricate the tap and I
ran the tap through it a couple of times. One side note; the linseed
oil made the threads swell up and the screw would not fit at first. After an hour
the wood soaked up the oil enough that the screw worked with no problem.
Below is a pic of my most useful marking gauges.
This is strangely part of my bucket list. I want to construct as much as
possible all of the tools of an eighteenth century carpenter and joiner like
the Dominy’s. Then I want to build a small cabin using those tools and outfit it
with the ironwork and hardware from my forge. Kind of strange I know, but I’ve given
up on the idea of getting a job at a living history museum (there hard to find) so I guess I will
make my own. 
