Headless bass guitars are similar to regular bass guitars with one major difference: They don't have a headstock, and the tuning mechanism is therefore located at the bridge. Headless instruments were very popular in the 1980s. The band Genesis used them regularly. They're still popular today due to the ergonomic design, which improves the weight distribution of the guitar. You can build your own headless bass guitar with a few basic tools and a standard bass guitar kit.
Purchase your bass parts either as a complete kit or as separate parts. You'll need to decide which wood and body style you want. A kit will include a body blank, a neck blank, pickups, wires, dials and hardware. Kits are standardised and made to fit parts, but you can do more customising if you purchase the parts separately.
Set up a suitable work area. You'll need a large table or work desk that is well lit, well ventilated and has adequate power supplies.
Measure up all of the bass hardware and plot the dimensions of the cavities on the body blank in pencil.
Customise the bass body blank. Your body blank will come in a traditional bass guitar shape. Depending on your woodworking skills, you can alter the shape of the body blank. Use an electric drill and hacksaw to make a cavity for your volume and tone dials, bridge and pickups. Remember that the bridge also houses the tuning mechanism, so the cavity will need to be bigger than average. Your pickups and bridge will need to be located centrally so that the strings run from the neck, directly over the pickups to the bridge.
Insert the pickups and dials and wire them in. Use a soldering iron to wire the pickups to the dials and the input jack. If you are unsure of the wiring, consult the pickup schematic. If you don't have the schematic, you can view standard ones online (see Reference 2).
Customise the neck blank. You'll need to saw off the head, leaving approximately two inches above the nut. In that two-inch space, use a nut slotting file and drill to make a hole for the ball end of each string. The hole should be completely level with the corresponding part of the bridge so that the strings run straight from the head to the tuning mechanism.
Attach the neck to the body using a good-quality polyvinyl acetate. The neck should slot neatly into the neck joint. Let the glue dry. Once the body is complete, smooth the finish with sandpaper.
Fix the bridge in place by gently placing it in the cavity and screwing it into body of the guitar.
Paint the body, if desired, before putting the strings on. Apply a primer, paint it, then leave it to dry.
Put on a set of bass strings.
Practice your cavity carving on scrap wood first, so you don't damage your body blank.
When soldering or using polyvinyl acetate, make sure the room is well ventilated.