Posted by jrjenks on Friday, November 28, 2008
My sawed-off banjo is a shortened 5-string banjo. Basically, I took a 22-fret 5-string banjo and whacked off the top 12 frets, creating a shorter, 10-fret instrument that's pitched one octave higher.
Here's what it looks like, compared to a 5-string banjo.
I wanted to work up a sawed-off banjo so I could:
Here's how we created my sawed-off banjo. By "we" I mean me and my business partner, Don, whose woodworking skills and well-equipped workshop were essential to the project.
We sawed off enough of the neck to expose the truss assembly. (See video.)
We used a Dremel to cut the truss assembly into two parts that could be pulled out of the neck. After cutting the truss assembly apart at both ends, used a hammer and a vise to whack the truss assembly loose. (See video.)
After measuring the banjo neck at both ends we created a jig to hold the banjo neck perfectly perpendicular to the saw blade, then used a miter saw to cut the neck off just above the 12th fret; hereafter referred to as the zero fret. (See video.)
We created a jig that held the neck so we could cut a notch in the neck to accommodate the spline. This notch runs parallel to the surface of the fretboards. (See the video.)
We used a miter saw to cut our piece of mahogany at a 72 degree angle (see video) and created a pine jig with an 18 degree angle cut. This let us cut a notch for the peghead which fit the spline and which held the peghead at an 18 degree angle. Our plywood spline fit not-quite-snugly in the notch. We wanted to leave some space for the epoxy. Then, using the same jig, we cut an notch for the nut at the base of the peghead. (See video.)
Using the diagram as a guide we used a band saw to cut the mahogany block to the snakehead shape then straightened the edges with a table sander. (See video.)
We wanted the peghead to be 3/4" thick where it connects to the neck, but 1/8" thinner (5/8" thick) along the edge where the tuners attach. So we rabbited out a trench along each side of the back of the peghead. (See video.) Then we rounded the outer edges of the peghead with a hand sander. (See video.)
Next we needed to create a custom, five-notch nut. We started with a plain nut blank, used a table sander to shave off some of the nut blank until it was the right height (see video), marked the nut blank to indicate the top of the fretboard and marked the location of the five notches (one for each string).
We put the nut blank in a vise and used a saw to start each groove. (See video.) Then we used a triangular file to cut each notch to a depth just above the desired depth. We didn't want to get the depth exactly right; that came later.
With the neck notch, the peghead notch and the nut all cut, and with a little creative vise placement, we used epoxy to put them all together very carefully and vised them into place so the epoxy could set.
After the epoxy had set we needed to cut off the excess nut and spline material. So with the help of some clamps, a file, some sandpaper and a Dremel (see video) we cut and filed and sanded and sanded some more until everything was smooth.
We put graphite in the grooves (see video), then it was time to adjust the depth of the five notches in the nut. One string at a time we strummed the string and tapped the string against the zero fret. If a string changed tone when it was pressed against the zero fret, that meant the groove in the nut wasn't deep enough so we deepened the notch just a little with a file. (See video) We repeated the process until each string was lightly touching the zero fret (see video.) (See longer video explaining all of this.)
That was the last step. My sawed-off banjo was ready for the world!
Friday, November 28, 2008 @9:02:38 PM
That ain't right!
Friday, November 28, 2008 @10:10:47 PM
Ah, but it's fun and practical to have banjos of different sizes and tunings.
Friday, November 28, 2008 @10:12:45 PM
Cute! Very interesting! Are you going to go into business?
Friday, November 28, 2008 @10:28:29 PM
Nice work, JR. Because of the short neck, the kind of spline you used may hold. In the future, especially for longer necks, let me suggest using splines that run parallel to the neck. Did you catch that plural? For aesthetic purposes, the splines can be a contrasting hardwood (redwood, ebony, mahogany, ash, cherry, etc.), and/or you can stain them a different color if you let them show from behind (the back of the neck) or the front (the peghead). You can hide the splines altogether, if you prefer. I don't think you can let them show front and back if you are not adept at gluing blocks of wood together.
What kind of epoxy did you use? I've had bad luck with epoxy when flexing was required. A flexible kind of epoxy, like the ones used to repair car bumpers might work well. You should bring your little 'jo to the next Costello Jam so that show off your handiwork, and so that we may more fully share your joy.
mike gregory Says:
Saturday, November 29, 2008 @5:56:19 AM
Well done! And the many detailed photos are a great plus.
Saturday, November 29, 2008 @6:51:41 AM
> FiddlerFaddler Says:
> You should bring your little 'jo to the next Costello
> Jam so that show off your handiwork, and so that we
> may more fully share your joy.
We missed you at the last jam! I brought it and played it for a few songs.
I'll have it at the next one. See you on December 7th?
Sunday, November 30, 2008 @5:26:51 AM
Beautiful job and great photos. Another approach to attaching the peghead is to use a 15 degree scarf joint - this gives a large glue area (I used Titebond glue with clamps). I built a jig to do this cut on my table saw, but next time (if there is a next time) I will probably make a fixture to hold the work piece and cut it with my router for more accuracy.
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