By Jon Fisher
"Genius is about 2% inspiration & 98%
I once had a book called "How to Survive in
the Wilderness with a Knife and this Book".
I figured why not get your knife and go into a
camping store and rob it so you can have all you need in
the wilderness. (Sorry, bad joke)
I am in the situation where I am building a guitar
but there is not a lot of availability of guitar parts
in the country I'm in. This means I need to make my own
truss rod. It would be a lot easier and probably better
if I was to just buy one for about 10 bucks but like I
said, there isn't one available.
I got the Idea to make one similar to the ones they
use in Martin guitars which is a piece of aluminum U
cannel that is bowed by a threaded rod that's inside.
As simple as it may seem, I had to do some
experimenting and there was some tedious tasks I had to
perform in order to get the desired effect. (Quite a lot
of work to save 10 bucks).
Here is the 1/2" square aluminum U bar I used. I
almost used a 3/8" one but I figured it will have to be
strong enough when bowed to bend the neck of the guitar.
I then ground down the height of the bar to 13/32" to
get it closer to how they do the Martin truss rods.
I was going to originally use a 3/8" threaded rod but I
had a real hard time finding one, so I welded a 3/8" bolt on
a piece of 3/8" rod to extend it to the needed length.
The idea is to use the aluminum bar as a type of bow and
the steel rod is like the string of the bow that when
tightened with a nut on one end of the rod, it will bow the
bar which is inside the neck of the guitar.
In order for the rod to grip the ends of the aluminum U
bar correctly I made some ends out of aluminum stock. I used
aluminum simply because it was a lot easier to work with
then steel. In the end that is shown in the picture I put a
groove on the far end so that the steel bar could be
anchored so in would not be able to turn when the nut is
tightened on the other end. I welded a ball on the end of
the rod then filed it flat so it could rest in the groove of
the end piece when assembled. I also beveled the 2 top edges
so that the U bar can be crimped around it. The hole in the
center is 3/8".
Here is one of the end pieces in place (un crimped)
inside the U bar.
Here is the end that has been crimped . You can see the
ball that has been wielded on the end of the rod.
Above is the rod assembled inside the aluminum U bar.
It's difficult to see but there is a nut and a washer on one
end. You will notice that I wrapped about 3 or 4 layers of
masking tape on 3 places of the steel rod. This is to avoid
any possible vibrations in case the rod happens to touch the
walls of the U bar.
I also slightly bent in the walls of the U bar in order
to assist the truss rod in bending the desired direction
when tightened. On the left is a rough idea of bending the
sides in looking end on at the U bar.
After the truss rod was assembled I laid out a strip of
masking tape. I stuck on a 1/4" strip of paper in the middle
of the masking tape, then pasted it over the open end of the
truss rod. This is to assist in preventing any rattle or
vibrations once it's installed in the neck. The paper is
stuck on the masking tape so that there is no chance that
the making tape will stick to the steel rod.
Here it is with the tape on. This side will go face down
in the groove that is cut out in the neck of the guitar.
This truss rod that I am using for an electric guitar is a
total of 17 1/2 " long. For an acoustic guitar it would be a
Here is the board that I am making the neck out of.
Although it is acceptable and practical to sometimes
laminate pieces together for a neck, this is to be all one
piece. It is 3/12" X 2" by 26". (quarter sawn). It's a piece
of Mahogany that I found laying around from an old table
that is probably older than me. (and that's pretty old).
It's probably pretty stable wood as when I checked it with a
straight edge, it was as straight as an arrow.
After making sure the top and side was flat and square I
routed out the 1/2" groove for the truss rod. It's important
to make the groove at this stage of the game while you have
a good straight surface to work with before carving the
neck. You can use a router or a circular saw works good too.
When using a circular saw you can set the depth you need on
the saw and then make multiple cuts to the correct width of
the channel using a guide. I usually tape the guard up when
I do this but you really have to be careful or you can have
a serious accident and lose your fingers and you'll be
playing slide guitar for the rest of your life. (No joke
It is my belief that the truss rod should fit in such a
way as it is not too lose or not too tight. If it's too
loose it could rattle around later. If it is too tight it
will not be able to freely move and bow correctly when it is
In cases when the groove was cut too big and the truss
rod is too loose, you can always put a strip of felt in it
to keep it from rattling around.
Well it's time to start on carving the neck. If you have
any questions or suggestions, please write me.