As I mentioned previously I was planning on building tracing templates from MDF so I could build more than one body down the road. This would also allow me the luxury of test fitting the parts together and having a better visualization of the final body, not to mention the ability to make adjustments to the design before committing to a final build. After tracing my design on to the 1/8" MDF panel (the top surface of the body) I cut this out with a band saw and got the shape in place. You can get equally good results using a scroll saw or a jig saw. If you are really hard-pressed and want to do it by hand you can get excellent results using a coping saw. I made allowances for the letting-in of the neck on this layer. If you cut your wood slightly beyond the pencil line and shape the rest of the way with files and sandpaper you will get an exact final product.
F-Hole:
When I was comfortable with the shape (test fit in my hands and along side my body), I proceeded to lay out the F-hole shape. For this I started by drilling a 1/4" hole in the largest area of the F-hole and used a jigsaw, (or coping 8" saw) to cut out the rest of the hole taking care to approach the pencil line leaving about 1/16". When I've removed the bulk of the F-hole I will remove everything else up to the pencil line carefuly using half-round files for the bulk of the work and needle files at the tips. To keep the tips from forming splits downs the grain later, we will drill a 1/16" hole at the tips.
Cutting Slab Layers:
Now in order for me to create my templates for each layer I have to repeat the shape on all layer panels which there are four in total. (bottom, mid-bottom, mid-top, top). Here I am showing the general shape for the panels. The left image represents the shapes for the bottom two layers and the right image represents the top two layers. (notice the area for the neck to key into).
After cutting out the design onto the MDF panels with a bandsaw, (again, you can use a jigsaw or coping saw following the same proceedure as the top panel you just finished), I went to the next step of fastening them together with wood screws to make for easy alignment when cutting the chambers out. You do not want to do this because the purpose of using screws was for to assemble the prototype and be able to take it apart and analyze the work.
The alignment is critical as the letting-in for the neck is already established with the top two layers as well as pickup positioning. I proceeded to lay out the chambering for the middle two layers. Make a note here that the chambers are different on both panels. They can be treated as the same internal shapes until you get to the center of the body that the neck-line follows. The chambering must be open here to allow the passage of air between the left and right side of the body yet be rigid enough to support the stress of string tension and not warp.
Also I took into consideration the contour on the lower back body that would allow me to have the bass body contour around my hip. Not all bass designs have this feature but I wanted it for comfort. proceeded to prepared the slightly over sized cutout for the pickup. The top layer (surface) would have a very precise cutout for the pickup. I also decided to keep the cavity for the electronics separate from the chambering areas as I would need to shield this later as well as allowing access to the circuitry. I had to design this cavity shape around the contents that would go into it. Here I am showing the panels from (1) Bottom, (2) mid-bottom, (3) mid-top, (4) top.
Note: I should point out that I've already taken a router bit to the edges of this design. This step won't happen for you here but I had to explain this because some of the pictures show the radius. Remember I'm designing some aesthetic components on the fly and need to do this to test things like wall thickness at the edge radius which in many cases gives us 1/4" of wood.
These images better show the effect of the chambering with the circuit and pickup cavity, I think the F-hole looks cool and certainly not traditional. Note the countersunk holes for wood screws on the surface. This really served its purpose well for dry-fitting parts together. I don't think I would ever suggest using screws to hold the body parts together on the final build. I could imagine some manufacturers in foreign countries might try something dumb like that to make things cheap, (cheaper than this bass even).
A couple of things I want to bring to your attention include the contour on the back of the bass for hip comfort. When I created the initial design I wanted to include this feature. Because the body is relatively small I wanted the contour at the bottom of the bass (I prefer to sit to play) and this is somewhat experimental. You can choose to add this feature in or not. Realizing the small space I have to work with I must contour around the circuit cavity and the inner walls of the chamber. The hip contour doesn't have to be very large but pronounced enough to make a noticeable difference over not having any contour at all. So while you study the next image you can get the idea behind my methodology.
The back panel has the defined line I'm going to follow for the contour and the inner chambers give some indication as to the amount of room I have to work with. When the whole body is assembled I'll take this contour out using a belt sander although it can be done just as well with a semi-round aggressive rasp without spending too much time on the job. Afterward the edges will be smoothed out and should perform the task eloquently.So far these panels took 6 hours to prepare and cut which brings us to a total of 16.5 hours in all.
