Monday, July 13, 2009

The NST banjo

Well, it's finally here, and mostly done. I now have a working banjo, with a twist (those of you who know me don't need to snicker so loudly). Instead of the standard banjo tuning, I have employed the intervals of the top four strings of the Guitar Craft (New Standard) tuning, so I'm dubbing this the NST banjo.


(Click to enlarge any picture!)


The brief history


A "Cumberland Banjo" kit was ordered about two years ago, from Musicmakers in (Stillwater, Minnesota, of all places), and it was early last year that I started to work on it. The design intrigued me--it's a small, open-backed banjo with a couple of nifty features including a cleverly adjustable angle on the neck, and an interchangeable insert in the fingerboard that allows you to use either the standard first three frets, or a fretless insert. It seemed something that I could try my hand at to see if I enjoyed the woodworking, and if I could actually make a playable instrument from the kit!

Things didn't start out so well. While trying to shape the peghead, I put too much stress on the joint where the nut is glued in (the kit's neck came rough-fabricated, with the fingerboard already glued on, truss rod in place, 5th-string peghole pre-reamed and tapped, and nut already in place, with the neck rough-shaped) and put a telltale hairline crack in it using an inappropriately underpowered jigsaw. I was not pleased, and put the kit away, disgusted with myself. About along that time, the move to Alaska started up, and I didn't resume building the kit until June of this year. I sheepishly got on the horn with Musicmakers, described the problem, and got the encouraging opinion that I could probably try to force a little glue in there and just glue the hairline back together, proceeding as normal. Because of the specific place the crack was located, the tension of the strings will tend to pull it closed, not open, and between the wood glue, re-epoxying the nut in place, and the strings pulling the crack closed, it seemed to be a good risk (and so far, so good!).

And so, while I assure you I am no sort of nascent Dan Erlewine or Ken Parker, I did manage to build the banjo, learning a great deal in the process. It was a lot of fun.

In this picture, note how the tone ring tensions the (8") plastic drum head. Six cap screws abut directly on the tone ring--simple but effective. The angle in this pic is a bit tough (I'm no photographer either), but you can just see two screws at the bottom of the black plastic tone ring.




The "tailpiece" is another ingeniously simple design, five pins sunk into the banjo's body and draped over a leather strap.




How's this for a first-timer's gaffe: notice anything unusual about this photo of the neck and headstock?




If you look closely, the eagle-eyed may notice that I managed to put the tuning machines on backwards! (Thank you, thank you.) I was so careful about shaping the peghead, after almost destroying it initially, that I just fit those machines on it in the manner most conducive to how they fit, and I got lefts and rights backwards without even realizing it! (The little "point" on the machines is supposed to point down, not up.) How's that for a truly customized banjo? I foresee continual amusement while playing the tuning song on this one...

Next pic is of the body. Eight-inch drumhead, and a standard five-string banjo bridge. Of interest is that this picture was taken before intonation. It became clear very quickly that the bridge was set too far forward, and after about 10m of work intonating, I've got a good position for it, very slightly compensated with the traditional bias towards longer bass strings.




Below, a shot of the banjo back. Note the two cap screws holding the neck joint. The top one is the tension screw; the bottom one abuts against a brass plate on the neck itself. To adjust the angle of the neck, loosen the top screw, then set the angle with the bottom one, retightening the top when finished. That was the fastest "action job" I've ever seen!




Interestingly, the action is limited on this instrument by the string height of the fifth string. At the neck joint, it is dramatically lower than the other four strings. I may at some point try to lower the action more, both by taking the main four strings down at the nut and filing slightly deeper notches in the ebony bridge for strings 1-4, but first I'm going to take some time to learn how to play it as it is!

This last picture doesn't really show this string height disparity, but it does give you an idea of the fifth string peg, individual "nut" (machine screw) and fingerboard. The fingerboard is made of padauk wood, a beautiful African hardwood with a lovely red color. (The rest of the banjo is of cherry wood, finished with plain clear lacquer.)




All in all, I'm reasonably pleased with my work. Doing the dot-inlays was an educational task, but I got it figured out and sanded that puppy to glassy smoothness with a final pass of 600-grit sandpaper. Fretwork turned out all right, with decent bevels and a minimum of sharp edges. The Dremel drum gave me one "oops" on the side of the fingerboard; otherwise I am pretty happy with it.

I learned a number of lessons, in addition to the ones noted above:
  • The Dremel is your friend, but there's nothing like hand-sanding for final shaping and detail work.
  • I do seem to enjoy the work with details--polish sanding, intonation, action setup, etc.
  • That 5th string tuning machine is not geared (the main string machines are 14:1). So far it has not been a problem, but I can envision getting excited and working that one too far either way at some point!
  • What to do with the string-end on the 5th string. Since it's a very light-gauge string (.010), the cut end is sharp, and although one should not have one's hand in a position to contact it during normal play, if it does end up making contact, there's gonna be a hole in your hand. I think I'll find a way to trim the string end so that the end loops back into the hole, presenting a smooth surface. Just seems smart!

So now what?

I got this banjo because I love the sound of the instrument, and of course I have a love of bluegrass-related musics. Being essentially a resounding mutt by disposition, I envision trying to use this instrument in bluegrass/newgrass, jazz, Crafty, and other contexts that haven't occurred to me yet. So, the fact that it's not a "bluegrass banjo" doesn't bug me (the sound is rather cool, actually) nor that I've adopted a different tuning for it.

Learning to play the banjo will be an interesting journey. The right hand clearly has a lot to learn, as I have thus far used a flat pick in Guitar Craft style, and my physical programming runs pretty deep. My intent is to apply a Crafty approach to it and see what happens.

The tuning, from strings 5-1, is:

G4 - C3 - G3 - D4 - F4

The main four strings (4-1) are the same intervals as the top four strings of the Guitar Craft tuning: a perfect fifth, a perfect fifth, and a minor third. (The standard banjo is tuned G4 - D3 - G3 - B3 - D4, with intervals over the main four strings being a perfect fourth, a major third, and a minor third.) My thought here is that it would allow me to use the same music theory on the banjo that I am learning for the guitar, and avoid me having to learn another set of intervals. (It will certainly also have the effect of giving this banjo a different voice, with chords very broadly spaced in the bass register and closely spaced on the top...and, duh, it's bound to be a PITA for someone else to figure out, which is always good for a larf. :-)

Anyway, the instrument is essentially done, with leeway for a little refinement on setup. I've got a strap fixed to it now (buttons at two and eight o'clock on the rim) and am ready to start the learning process!

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