trib - Posted - 12/07/2012:  14:10:34

I've acquired a nice Beltone tenor banjo neck. It's 3-ply, bookmatched, nicely quilted maple, 17 frets, and a 13.5" inch fingerboard length. I love the very compressed scale of this shortened fingerboard.

For some time I've planned to make a custom clawhammer neck — wider, shorter, with frailing scoop. I had expected to modify a spare 5-string neck to "A scale" dimensions. Now this tenor neck is giving me flights of fancy. If I mated this shortie neck to my 11.75-inch Luscomb pot, what are the predictable effects in pitch? Would this hybrid instrument have to be tuned way up in pitch to get good string tension? I'm using medium gauge nylgut springs and hoping to find a fiddler to play with — hence the pitch compatability question. If there's a URL explaining scale length and pitch to a mathematical dummy, a link would be appreicated.

TIA for the advice.

mbanza - Posted - 12/07/2012:  14:35:20

Scratch around in here, Randy has lots of information:

banjohangout.org/myhangout/hom...p?id=3035

trib - Posted - 12/07/2012:  19:43:55

Thanks for the lead. Great site, and I've been scratching there and elsewhere ever since.

Let me rephrase my earlier question. What would folks recommend for an A-scale for an 11.75-inch pot?

mbanza - Posted - 12/08/2012:  07:08:17

You can still tune a short scale banjo to "normal" pitch by using steel strings that produce tensions of 13 to 16 pounds each.  Nylon strings will behave similarly except that they will sound fine an lower tensions, say 9-15 pounds each.  You can estimate steel string tension with this handy free download:

kennaquhair.com/ustc.htm 

One note:  There is no 0.018 wound in this program, but the tension for 0.016 plain is about the same.

You will have to arrive at estimates for nylon from the information here:  liutaiomottola.com/formulae/tension.htm

and here:  daddario.com/upload/tension_ch...13934.pdf

Your scale will be about 20.6" and my experience tells me you could use the first four from a classic guitar plus a second first string for a fifth and tune to "G" at acceptable string tensions.  You would probably have to use the heavier nylgut set.

Fathand - Posted - 12/08/2012:  07:44:09

How do you plan on adding the 5th string for clawhammer? 

You can determine your scale length by measuring from the nut to 12th fret and doubling that distance.

An A scale, if using an off the shelf set of  light or med. steel 5 string banjo strings, should have a scale about 23-24".   Your 17 fret tenor likely has a scale in the 20-21" range which would make it about a B or C scale. 

Tenor banjos were built late enough that they were usually designed for steel strings, since their purpose was volume in the pre-amplifier age.  If you want to use nylon strings and tune to open G or any tuning close to that, I would get a set of Baritone ukulele strings. You can buy a spare 1st for the 5th string. Or, if you leave it as a 4 string, with nylon strings you will essentially have a Baritone Banjo Ukulele.

trib - Posted - 12/08/2012:  19:33:48

Thanks once again, mbanza, exactly what I was looking for. Please let me reserve the right to ask followup questions after more detailed reading and thought, as I'm sure I will have some. Most of my playing was done in the 1970s, where in rural northern New Hampshire you played whatever strings you found at the local one-size-fits-all music store. This boutique stringing concept is new to me but sounds very exciting and the ideal way to customize the sound I want. I've decided conceptually to proceed with mating the tenor neck to my 11.75-inch Luscomb pot. The tenor banjo lacks a bridge but the 12th fret is 10.5 inches from the nut, so that would be a 21-inch scale. And I measure from the peghead side of the nut, correct, rather than the fingerboard side of the nut?

Chris

Fathand, I haven't finalized the drone string placement. Probably will add a small "wing" up the tenor neck from the usual 5th fret location. The quilted maple neck is handsome so I want to minimize the ugliness of the wing. I've seen 5th strings added where they run over nothing (that is, with no fingerboard beneath). Since I rarely play above the 12th fret, I'm thinking about installing the 5th string there, or even a fret higher. I'm going to have to construct a scale template on graph paper, tape it to the existing neck, and contemplate this mess. I'd like to get the 5th string tuner out of the way of my left hand, but it can't be so high up the neck that it impinges on a wide and deep frailing scoop. This baby will be a semi-fretless with brass flush frets 1-5. I have a beautifully colored and grained piece of inch-thick cocobolo for the fingerboard.

What I will be doing is fattening the tenor neck. We'll saw it down the middle, and add laminations to get the fingerboard width at the heel to at least 2.25" for better, wider string separation. Will similarly reinforce the sub-fingerboard top of the neck with laminations. Building up the height of the neck profile will allow for the half-inch scoop I want. I'm really trying to build an instrument that compensates for my playing weaknesses and physical limitations. I don't want a banjo-uke, I want an oversized pot clawhammer instrument with at least a little growl and thump in the low end. Thanks for the suggestion about ukelele strings. I expect to stick with nylong or nylgut of one sort or another.

oldwoodchuckb - Posted - 12/09/2012:  03:11:30

My current main playing banjo was designed from a 17 fret tenor I own. The neck was built as a 5 string. I've got to get my wife's camera and take some pix of her. I call it a "B scale neck since the scale is well under 22 inches.

I use a Dean Markley medium-light string set but take out the 15 and replace it with a 16. Because the 5th string is extra short (starts at the 8th fret) I use a 13 or 14 for that - essentially I'm using it to slowly use up my remaining "orphan" strings. Needless to say I have a large supply of unused strings after 50 years of playing guitar and banjo.

Edited by - oldwoodchuckb on 12/09/2012 03:18:47

Fathand - Posted - 12/09/2012:  04:28:58

Sounds like you would be just as simple to build a new neck from scratch. You are going to have to build a new fingerboard anyway and it will be difficult to accurately split the current neck since it is not a square item.

Nylgut is famous for Uke strings by the way. I wouldn't use any other on my ukes.

quote:

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Originally posted by trib



What I will be doing is fattening the tenor neck. We'll saw it down the middle, and add laminations to get the fingerboard width at the heel to at least 2.25" for better, wider string separation. Will similarly reinforce the sub-fingerboard top of the neck with laminations. Building up the height of the neck profile will allow for the half-inch scoop I want. I'm really trying to build an instrument that compensates for my playing weaknesses and physical limitations. I don't want a banjo-uke, I want an oversized pot clawhammer instrument with at least a little growl and thump in the low end. Thanks for the suggestion about ukelele strings. I expect to stick with nylong or nylgut of one sort or another.

 

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mbanza - Posted - 12/09/2012:  06:41:57

Q:  "And I measure from the peghead side of the nut, correct, rather than the fingerboard side of the nut?"

A:  No, measure from the finger board side of the nut;  you are measuring the vibrating portion of the string.

cockneybanjo - Posted - 12/09/2012:  08:11:47

the spacing of the frets is calculated relative to the scale length, which will determine the scale length of the finished instrument - basically, twice the distance from the nut to the twelfth fret. This determines the bridge position. 

This all sounds an awful lot of work for no predictable outcome

tomberghan - Posted - 12/09/2012:  08:22:31

Being a fan of both 4 and 5 string banjos as well as the various instruments of the early 20th century, please keep all of the banjo's original parts and don't modify any of them. If you want to make a new neck and convert to a five string - fine - but please don't lose or discard the original neck and parts. I just hate to see 4 string banjos essentially lost in the process of conversion. Do your conversion such that the banjo can go back to its original form at anytime in the future. Best Wishes! Tom

cockneybanjo - Posted - 12/09/2012:  09:25:08

I'd agree. It sounds a great deal of work and for what? You could make a new neck for the same effort.

NYCJazz - Posted - 12/09/2012:  09:53:12

I think you guys are overthinking this.

You are aware, aren't you, that tenor and traditional 5-string tuning have three notes in common... CG&D. I have used classic 5-string banjo Nylgut strings on a tenor for CGBD tuning. I use pretty much the same gauge steel strings on both tenor and plectrum for those common notes.

trib - Posted - 12/09/2012:  15:04:31

Thanks for the input, all. Fathand, my son is getting the Beltone's birdseye/rosewood pot as a Christmas gift. He's the working foreman in a high-end millwork and architectural detail shop. Their work is all commissioned, mostly for millionaires and always done to prepared architectural drawings. Their clients are people like John Henry, the hedge fund billionaire who is principal owner of the Boston Red Sox; their waiting list is months to years. Woodworking technique and skill is not an issue here (though it certainly would be if I was trying to do this myself).

When I asked Caleb how he would symmetrically bisect a very unrectangular banjo neck, he looked at me like I was an idiot, and said, "Build a jig." Of course! Silly me, duh. Since the neck is already laminated (dyed black center stripe), the bisection is already laid out. These guys build and fabricate everything from scratch (i.e., raw lumber for the work, particle board for jigs, templates and forms). Caleb has reviewed all the woodworking plans, and contributed a beautiful cocobolo piece for the fingerboard from the shop scrap bin. (Nice scrap to have!) Could have been purpleheart or teak if desired.

Cockneybanjo, I'm afraid this Beltone tenor is destined for cannibalism. I saw a chance to acquire a thick (5/8), antique wooden pot for my son as well as the neck we're discussing to modify for my clawhammer style. (Wide and short fingerboard, deep frailing scoop, semi-fretless.) I've been looking for donor stock at an affordable price ($111) on eBay for two years. The neck is bookmatched quilted maple, and will be even more handsome as a wooden object once colored (red, white, black) lamination sandwiches are inserted. The existing fingerboard, which will be saved for scrap (assuming it's ebony), is generic, with minimal small diamond inlays, and therefore not rare or a significant loss. It's not like this is an Orpheum, Lange or Paramount instrument. (I owned an Orpheum 5-string 40 years ago, and once you've played the best …) The one desirable detail I want to save is the thick Beltone brand sticker that's mounted in a shallow cavity in the peghead. A horizontal diamond border encloses the BELTONE letters, of which the T is already gone due to a peghead veneer split over the neck lamination. Bottom line, I'll have a BEL ONE peghead. Or maybe I can add a Z and make it the one and only Belzone? :-)

NYCJazz, I'm persuaded that strings will be obtainable to get this to play at or near standard pitch with suitable string tension. I'll get to strings once all materials have been collected and the carpentry has begun.

New Question:

Is there a veneer supplier (peghead, heel cap) anyone would recommend in particular? Woodcraft Supply offers packs of dyed generic veneer for the sandwiches, but pretty expensive at $25 for three square feet of dyed pearwood or whatever they use.