J Bass Build Progresses
The Custom ‘T’ has now started the finishing process which means I can now move on to other projects. The J Bass build started a while ago and has seen the body machined up to the point of a few minor operations such as routing of the battery box cavity. In the meantime I have made a start preparing the maple neck blank.
Cutting maple stock to width on the table saw.
Unlike a traditional J Bass, the headstock will have a back angle, this will eliminate the need for string trees and will make the headstock stiffer and less prone to forward bend or twist, often seen on ‘flat’ five string headstocks. The maple is figured and was roughly planed flat before being finished to a touch over size on the drum sander. I’ve had the drum sander for about a year now and I have to say I don’t know how I managed without one for so long, it’s a godsend when preparing figured or difficult timbers.
Once the stock is flat and square I can cut the angle for the scarf joint. The angle is not that steep, I use 10 degrees which is enough to create a string break angle over the nut and not so much that it results in a shorter, weaker joint. I cut the angle using a jig on the table saw. With a sharp, clean blade I can cut the gluing faces in one pass. Ocassionally I need to do a second light trim if vibration has maybe caused a ripple in the cut faces.
Using the table saw to its full capacity to cut the joint.
With the joint cut the two parts are glued. This type of joint is very prone to glue slip and requires both parts to be clamped to prevent slippage before the actual gluing faces are clamped. The joint is left overnight to cure.
The prepared joint glued and clamped.
If anyone is wondering why I use a scarf joint then please let me explain, a few people do see it as an aesthetically inferior means to produce an angled headstock. The weakest part of any guitar neck is in the area around the nut, the thinnest and narrowest region. A one piece neck is particularly weak in this area due to the run of the grain fibres. By using a scarf joint the fibres in the timber run parallel with all long faces of the neck, ie there is little run out of grain fibres into a face. This dramtically increases stiffness and strength at the headstock. The nature of modern glues also means that the timber will fail before the glue joint does. An added benefit is it’s considerably more material efficient than a one piece neck.
A graphical explanation of why I use a scarf joint.
Once the glued blank is cured I can dress the fingerboard gluing face. Again this is done with the drum sander. To enable me to allow for the headstock angle the neck blank is supported on a wooden block.
Usingthe drum sander to dress the fingerboard gluing face.
Next, I will cut out the neck shape, route for the truss rod and prepare and glue the fingerboard.