Making Your First Guitar
A Tutorial
The Neck
At this point, you should have used your template to cut the wood to the basic dimensions for the neck and body of the guitar.
Start by joining (laminating) two pieces of the stock you have chosen for the neck together. The two pieces should appear natural. Such as: (((((()))))) or /////\\\\\ . Not /////=====)) .
After choosing the orientation of the grain, make sure the sides to be joined are absolutely flat to ensure an invisible seam. This can best be done on a jointer or planer. White or yellow aliphatic carpenter's glues are usually used here, although polyurethane glues are now coming into favour. They gain strength with moisture and have a superior hold on many exotic woods that secrete oils.
Once glued up, clamp the pieces lightly in order to hold them in place, but not enough to squeeze the glue out of the joint. Allow to cure at least overnight to be safe. Only after it has been cured should a trough for a truss rod be routed out of the stock.
Truss Rods
A truss rod is a metal rod which runs through the neck and protrudes at either the head stock or at the body where a nut of some sort allows adjustments to be made. Early truss rods were of the compression variety. In essence, this was just a metal rod anchored at one end which would put tension on the neck, compressing it by applying a force in the opposite direction to the force of the strings. The strings want to bend the neck upwards, so the truss rod is adjusted to force the neck downwards by the same amount, thereby making the net force zero. This assists in keeping the fingerboard flat and adds stiffness to the neck. Newer double expanding truss rods have an adjustable rod welded to a fixed rod so that when the nut is tightened, the rod itself bends and creates a force in the desired direction. A single truss rod is generally sufficient for a four string bass, but you may want to add a second, parallel one in wider necks designed for 5 strings or more. When cutting troughs for the truss rods, you can also cut troughs for carbon fibre stiffening rods if you wish to incorporate them. These are very strong and stiff despite their light weight and can further stiffen the neck and keep it flat.
I carve out the truss rod trough on a router table, using a router with an edge guide. A table saw with a regular or dado blade could be used. Using a straight cutter bit of about one half inch (wide enough to accomodate the truss rod) , I plunge the wood down on the cutter where I want it to anchor (to end) and then feed it through the cutter until it reaches the area where it will be adjusted (i.e. the head stock or the body). The trough needed will probably be too deep to make in one pass, so set the depth to about a quarter inch and increase with subsequent passes until you reach the desired depth.
Once the truss rod trough is complete, you can attach "ears" to the end of the neck where the headstock will be. The material for the neck is usually not wide enough for the headstock, as the headstock serves to hold the tuning pegs and the gears on the back may be more substantial in size. The headstock can be flat (parallel to the fingerboard surface) as a Fender Precision Bass, or angle away from the fingerboard surface at some predetermined angle, usually around 10 degrees, as a Gibson EBO Bass. The angled headstock keeps the strings secured firmly in the nut with the tension created by the angle; whereas, the flat headstock usually relies on some sort of string tree under which the strings travel to the tuning pegs, creating the necessary tension.
What you essentially have now is a long block of wood with a groove in the top and extra pieces of wood at one end to allow for the full dimensions of the headstock. Tracing the outline from the blueprint on the top and sides of this block gives the shape of the neck. I find it easiest to use the bandsaw to cut the headstock as it is accurate, fast and can take tight bends using a quarter inch wide blade.
Leave enough material so that the final dimensions are approached with wood rasps and achieved with sandpaper. A belt sander can be used to true up the face and back of the headstock once cut out. Blade marks from the band saw generally remain and have to be removed. Once the neck itself is roughed out, I find a variety of tools work well to get the profile that I want. A spoke shave, coarse wood rasps (files) and coarse (60 grit) sandpaper disc mounted in an electric drill work well. Whatever works to get this excess material off the neck. Patience and care will get you to where you are going. It is harder, if not impossible to add back material at this stage, so work with caution.
On a through-the-body bass, mark where the neck will join the body on the neck and stay clear of shaping too far back. I leave this area until later to blend the neck to the body once the wings are attached. On a bolt-on, keep in mind the area of the bottom of the neck where it will attach to the body. This must be flat and at the appropriate angle you've predetermined for your neck for the hardware that you are using.
With both neck styles, be careful with the surface to which the fingerboard will be attached. You want to keep this flat and the edges crisp/sharp so as to make a good fit with the fingerboard once attached. This is not as cruicial if the fingerboard will be bound with plastic or other material, as this channel along the edge would be routed later and would obscure any defects.
Holes for the tuning pegs (and bushings) can be drilled at this time. Measure carefully (twice!) and drill. This is best done using a drill press, as it is much more steady than a hand drill, but it can be done with a hand drill by progressively increasing the diameter of the drill until reaching the diameter required. A flat bottomed Forstner bit is best as it reduces tearout on the opposite side of the headstock. Regardless, drill from the front to back, as any tearout will be hidden by the gear mechanisms. If using a simple twist drill, clamp the head to a scrap piece of wood and drill right through into the scrap. This, too, will keep tearout to a minimum.
Assembly
When making your very first instrument, it is advisable to dry fit it which is to assemble the instrument as if it were finished, although it is still in the white. This allows you to discover any problems that you might have while they are still easily correctable. Pre-drill holes for all screws that are to hold your hardware. This makes it easier when finished and you won't strip the screw or marr the finish when tightening up the finished instruement.
On a bolt-on neck guitar, it is important to have a snug fit of the base of the neck where it fits the body and to make sure this is perfectly in line with the body. You can measure the center point of your neck at the nut and push in a fine pin at this point for a reference point. Attaching a string to the pin, run it back to where the bridge will be. The distance will have been already predetermined by your scale length, so this procedure is more useful for lateral placement of the bridge. The string should also leave the neck where it joins the body at exactly the center. When you are satisfied that you have the neck centered, clamp the neck to the body.
Make sure the neck did not shift in the clamping step and, when satisfied, use an appropriate size bit to drill holes for the screws that will hold the neck in place. Drill only as deep as necessary to avoid unnecessarily weakening the neck and to ensure you don't drill through the top. Mark the distance you want to drill on the drill bit itself by wrapping a piece of masking tape around it where you want to stop. When this tape marker reaches the wood surface -- stop!
Some necks have just screws, some have ferrels (fancy washers) and some have a neck plate. A neck plate can be chiseled or routed into the wood of the neck to recess it, if desired. This does make the neck smoother at the heel. Whatever you use, make sure this contact point is strong and accurate. Attach the heads (tuning pegs), the nut, pickups and bridge. Using a string, a straight edge or, better yet, a set of strings in th gauge you wish to use string the instrument up. At this time, you can adjust the neck angle by sanding or plaining the neck at the point of attachment in order to bring the headstock up or down as required. This will determine how parallel your strings run to the fingerboard surface and how low you can take them down in practicality.
