How to Build an Acoustic Bass Guitar

1). Start with a semi-finished neck and body. You can cut your own with an electric saw and a lathe, but semi-finished bass guitars can be purchased from a professional luthier shop and will save you a great deal of effort while giving you the satisfaction of building your own instrument.
2). Drill the tuning keyholes in the headstock of your bass guitar. You'll want to cut the laminate covering for your headstock as well, matching the holes to the holes for the tuning keyholes. With a small router, make seating grooves around each of the tuning keyholes for hardware bracing. Skip this procedure if the holes for the tuning keys have already been finished.
3). Stain and lacquer the neck and headstock. Use a very light stain if you plan to paint your bass guitar. Use a high-grade spray paint to paint the neck and headstock. Finish it with water-resistant lacquer. Let the neck dry before proceeding.
4

Use a wood lathe to cut the truss rod channel in the neck. Make sure to get a truss strong enough to take into consideration the extra thickness of bass guitar strings. Seat the truss rod in the channel. Whether to glue it in place or not is up to you. Place a little silicone caulking in the channel to prevent rattling, and lay a thin piece of tape over the truss rod to keep glue from getting on it when you lay down the fingerboard.
5). Place the fingerboard on the neck of your bass guitar, and glue it down with brush-on super glue. Run your hand along both sides to ensure smoothness. Use a light-grit sandpaper to remove any rough edges.
6). Install the frets on your bass guitar. If the slot frets aren't already cut, you'll need to cut them yourself using a wood lathe or a hand saw. Tap the frets into the slots with a small rubber hammer. Use a file to remove the sharp edges of the frets. If the inlays are not already in your guitar, you'll have to use a jig and cut the placement for the inlays.
7). Stain the body of the bass guitar and let it dry adequately. Paint the guitar and apply lacquer. Let it dry thoroughly before fixing the bridge to the bass guitar with super glue. Glue the nut to the top of the neck with super glue at this time. If you're going to use a pick guard, now is the time to put it on the bass as well.
8). Attach the neck to the body. Make another pass to ensure there are no rough edges, then glue the molding to the body and neck of the guitar. This not only makes the bass look better, it provides protection from cracking. Let the molding dry thoroughly, then install the tuning keys on your instrument.
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String the bass guitar and tune it up. Do it gradually. Use an electronic tuner if one is available. Gradually bring each string up to pitch. Alternate between the strings as you do this. You want to avoid tuning one string at a time. The strings will go out of tune until they have stretched some. Once you've achieved a proper tuning, your bass is ready to play.