5 String Tenor Guitar

[P Bill]

Since building my little CBG tenor, I'm not exactly mad for tenors but very keen. This is as much an exercise in design as building for me. I've generated all the patterns and archs using Bob Benedetto's patterns as a guide. Only the waist is an arch, all the others are arcs from a compass plane. I don't know if this is good or bad. It seems right at this point. The back has a different arch pattern.

Finding tenor dimensions is hard. After I settled on an outline I found some on Dave White's site and checked mine against his. Upper bout and waist almost the same; my lower bout is almost 25mm bigger, that would be the archtop kicking in. I kept Bob Benedetto's upper bout, waist and lower bout relationship.

The ink lines are carved to the patterns, still working on the waist. Once the waist is finished I'll connect all the dots.
Of the tools pictured the round spokeshave, the compound toothing plane and the no. 3 fishtail do most of the work. I'll update before the neck goes on.

Any carve top input will be welcome.

Scale length - 23 1/4 in
body length - 450mm, 17in. archtop - 530mm.
Top and Bottom - 20mm th.
Sides - 60mm
lower bout -320mm
waist -177m
upper bout -208
14 fret neck join - bridge/ lower bout relationship positioned after this.

The 2nd photo shows the scale difference between a tenor, mandolin and a 17in archtop.

[Allen]

It's very similar shape to my ukes Bill, so I love it a lot. Can't wait to see this one progress.

[graham mcdonald]

There really are no rules for tenor guitars. There have been so few built in recent years that it all really becomes the choice of the builder. Essentially you are making an octave mandolin or cittern, with half the strings so you can really work off a graduation pattern halfway between a carved mandolin and a jazz guitar, with allowances for either a round/oval soundhole or f holes of some kind. With five strings are you planning a CGdae tuning? That takes you into what can be a problematic area acoustically. Stringing gets interesting when you are trying to find a gauge that will work as a top e and not have a huge ship mooring cable for the bottom C. It will depend on the scale length chosen. I think that there are sound scientific reasons why stringed instruments have a limited top to bottom open string range of no more than the two octaves of a guitar. Once you get past that there are problems of getting the strings at either end to work as well as they might. For your C string to work optimally, the air resonance should be around D#-E, and the main soundboard resonance about an octave above that. This could make it harder for the top e string to be as bright as it might be. From my experience with octave mandolins for that top e string to sizzle, the air resonance would need to be around B on the G string and that would mean the bottom C will sound rather thin. Your mileage may vary, of course.

I will be interested in hearing how this one progresses

graham

[P Bill]

Thanks for the interest fellas,

Graham very useful information and I'm taking it onboard, thanks. I've seen many photos of tenors the last month and no 5 strings, I think i just found out why. I think I have fb room to convert my cbg tenor to a 5 and experiment with that.

Thanks also for the air and soundboard resonance references. Since my bass string will be C are those refs. still in the ballpark?

[Dave White]

Bill/Graham,

The instrument I built for Bill Briscombe - "Doolish" is essentially a 5 string tenor guitar. We just made the third string an octave pair partly for the sound and partly so that there were six tuners on the headstock and it looks more balanced. Bill uses it in a number of different tunings and it works well - ADGgBE, GDAaDg, ADGgBD, GCGgCg



The octave pair was done as two slots cut in one bridge pin hole. Bill decided that for some flatpicking tunes the octave string got in the way and he takes it off for these. This left the string spacing out of kilter so I made a slotted special bridge pin for him for this purpose that centres this string and cut an extra slot in the nut:

[P Bill]

Hi Dave, thanks for the input.

My luthier learning curve is steep and seems a lot steeper on this one.
Talk about tunnel vision. I was looking for dimensions and that's all I found, missed the extra strings.
I plan on using the same mould and making my first flat top after this. With deeper sides, similar to yours.

My main reason for 5 strings was the look as well. Most photos I saw roaming the web showed a neck out of proportion to the body.

[graham mcdonald]

With your 23 1/4 scale a Cgda tuned tenor means a interesting mix of strings. Your top a string is going to need a pretty thick plain string, .018 or even a very light wound string. Think about it in terms of being between a guitar g and b strings with the lesser tension that the shorter scale will give. You will need a reasonable amount of tension to drive a carved top. Getting that string length tuned an octave higher might be possible, but with a very thin top string. It would be worthwhile doing some string tension calculations using my an on-line calculator such as the one on my website. It was for problems like these that I did it in the first place. You might be better to consider a gdae tuning, where a set from .012 to around .046 would work. Air resonance is going to depend very much on the air volume of the body, and I don't know any simple way of predicting that. I would hope that it would come in around C# for a good balance.

cheers

g

[Dave White]

What tuning for the 5 string did you have in mind Bill? I thought perhaps it might be CGDAE - taking the bouzouki range and adding a lower fifth - which in range would be like a guitar in dropped C with the third string missing and the low C would have to be pretty heavy - 56 or 59 maybe or even bigger. For the A string an 18 would work or perhaps a wound 20. If you had a four string in CGDA and wanted to stay in fifths and go lower then that would be FCGDA - sort of like 6,4,3,1,1 strings on a guitar - then the high A would need to be a very light string.

As Graham says though carved tops need more string tension and my tenors are ladder braced and arched but not carved.

[Kim]

Great to see you pop back in Dave, we don't seem to see enough of you these days. Anyhow merry xmas to you and yours from all at the ANZLF

Cheers

Kim

[P Bill]

Graham / Dave,
I was planning on a set of ordinary tenor guitar strings CGDA and finding an E. From what I've gleaned about tenors, 23 1/4in.
is a long scale and should give a fair amount of tension. The bridge will be near 25mm, that should add some more tension.

Just as a side note. The cbg tenor I made started to sag with banjo GDAE strings. I knew my tone bars were light, I was compensating for a PNG rosewood top. The bridge is 38mm high and that really gave it some tension. I knew that would move the top. I should replace the tone bars on that one before I close this box.

Dave that's very clever how you strung your tenor.


viewtopic.php?f=25&t=4892

[P Bill]

Top and bottom finish carved and rough sanded. Ready to bore and graduate. Insect attack on the back was discovered while carving. I'm still using timber at hand. This is no 6 in the carve top family and I won't buy proper timber or offically number them till I get to 10. I have more time than money. I don't think I would like to build an acoustic to order. Customer expectations can be a wild card.

I sold a bass Tuesday. The closest I come to custom: M. could choose from 4 bodys already chambered, glued up and ready for carving; 6 necks with pegbox morticed, cf fitted, pegbox veneers on and fb fitted, ready for carving. M. took a loaner away Sunday and I got the call tuesday. I'll be working on 2 builds.

[Phil Mailloux]

I sold a bass Tuesday.

Congrats Bill! I was wondering about that, I asked Wilma about it but she forgot to ask you.

[P Bill]

I'm back after a long lazy summer.

The pics speak for themselves. The bottom plate was to overhang like the top , my guide wasn't tight enough and I made a binding ledge instead.

The fb and head veeneer are False Sandlewood. I found a 13in archtop , http://www.earnestinstruments.com/earnest.html

I closed the box before photos, it's angled parallel bracing. The graduations are more like a mando than guitar. The braces are more like a guitar.

[ozziebluesman]

Looks great Bill.

Interested in the sound when finished.

Thanks for the pics

Cheers

Alan

[Kamusur]

Bill

I love the solid linings, headstock shape and bound fingerboard and was wondering if it (bf) was a little wider than normal (or just an optical illusion) also got worried when i saw the t/rod adjustment at the heel end but figure you must have a logical explanation. Also are they surfboards or skateboards in your avatar Bill?

Dave W

Great solution with the slotted string pegs, and wondering if the unused tuner is a worry with rattling or anything else unforseen Dave?


Steve

[P Bill]

Cheers Alan and Steve,

The nut is 44mm
14th fret 57mm

It is a little wider , the short scale compresses the look a bit. I didn't mention, now it's going to be strung as a 6 string guitar,
like a 23in Gibson Byrdland as well as the Dave White 6 string tenor option.

Skateboards. All Blackbean 12mm th. The diamond pattern has never had wheels , the other 2 have had a hiding.

[P Bill]

I forgot the trussrod. I'm taking a calculated punt on that. The extension is "boat coted " to a larger than normal dovetail.
I'm sticking the fb on with HHG, so it's reversible. The back is also HHG , in case I want to get back inside.

[Kamusur]

Thanks Bill, must be getting tuned in to wide fret boards my brother has massive fingers and they suit him to a tee. Skateboards looking good too.

Steve

[P Bill]

Another use for the tailvise. I'll have to reverse the 50mm nut for the bench screw and it will accomadate a 17in archie. Also, I'll make up inserts lined with rat fur. Horizontally, its just a 3 point rest.

The scraper is a " scratch stock " , the beads with the fielded rise are for French tables I used to do. The neck profile is " C " and " D ". I use it after spokeshaving. It's used it to quickly fair all the bevels before sanding.

[liam_fnq]

The joy of being a uke builder is that they fit in a standard woodworkers vice

[P Bill]

Hand stained and a very dilute poly, boiled linseen and and 75% turps coat to warm it up. It's hot and dry, I can start to french polish tues. I want an old look. The look changes with the viewing point.
I'll be working with dirty and clean blonde shellac. I haven't used bookmatched timber but I have matched the catoyance to avoid the night and day look of a bookmatch.

[ozziebluesman]

Hi Bill,

I am attempting my first re-build and replacing a top. I would like to keep and aged look so could you please explain your process of aging the Tenor guitar top. It looks fantastic and very vintage. My top is spruce and I believe you have a hardwood top on the tenor. Anyway, some advice would be great. I have applied a wash coat to the top just to stop any bleed from the black white black purfling and intend to apply a French polish finish.

Cheers

Alan

[P Bill]

Hi Alan,

I've been watching the re-build, it looks you'll end up with a nice guitar. Onya, because at this stage I wouldn't try it.

I am using Roger Siminoff's hand burst technique. He gets beautiful, seamless results. I have a way to go but I'm making a start. The difference is a transparent burst as opposed to an opaque one.

The basic rule is many coats of weak stain. If it's not working add a few more drops. My amber colour is Feast Watson maple, 1/8 cap ( or less ) in half a 375g peanut paste jar of metho. If you want a plain top that will probably work. I used the same ratio with F.W. walnut. After the walnut use clear metho to remove and blend. So my amber field has very dilute walnut as well.

Siminoff doesn't use dirty shellac (lightly tinted, still transparent.) I've seen polishers use it and I've done it many times. You could do that instead, It's safer and you'll have more control if it's just one colour. I've stained raw timber and am hoping to even the burst out a bit with dirty shellac and pull it together with clear.


auscab could probably shed some light on this as well. Rob, you out there?

[ozziebluesman]

Thanks Bill. The dirty shellac will be the trick for my project as I only want one colour. It id difficult for me as I am colour blind and can't see depict darker colours like purple and also reds and greens all look the same. My wife can come to the rescue. I wasn't sure what to use and how to go about it. If you have a look at the first few pics of the old top that is the colour I was looking at.

I would be interested if Rob has any suggestions too!

Cheers

Alan

[P Bill]

Alan, if you go with dirty shellac, mix it a bit stronger. You can stop at any time and continue with clean shellac or wipe the job clean and start again.