very well made & beeeeeaaaauuuutiful also!
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Mike
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| 12-String Slot Head Triple-0 http://luthiersforum.com/forum/viewtopic.php?f=10101&t=48565 |
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| Author: | SteveT [ Sat Nov 19, 2016 3:09 pm ] |
| Post subject: | 12-String Slot Head Triple-0 |
This is my 1st attempt at a 12-string. Here are some specs & pictures: Back & sides: Australian Blackwood (RC Tonewoods) Top: Engelmann Spruce (433 kg/m^3 density) Neck: Honduran Mahogany Bindings, Head Plate & Back Strap: Curly Koa Tuners: Antique Acoustics (pricey) (Elderley) Bridge: EIR Saddle: Bone, with individual string compensation Finish: French polish (CA pore fill) Top thickness procedure: Starting with known top density, I used some of Al Carruth's data & ideas to calculate what top thickness I would use if this were a 6-string guitar (0.107"). I then used D'Addario data to obtain the string tensions for a 6-string (EFT16; 171.5 lb) & a 12-string (EJ38; 252.1 lb) setup. The cubed-root rule was then applied: Thk-12 = Thk-6*(Tension-12/Tension-6)^0.333, or Thk-12 = 0.107"*(252.1/171.5)^0.333 = 0.120". I used an extra large heel block with an A-frame upper bout bracing (see pic). I also used extra bulky side braces to help keep the sides rigid & to add some mass to the sides. It sounds great! (And is loud.) |
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| Author: | johnparchem [ Sat Nov 19, 2016 4:14 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Wow! very nicely done. Nice design, also I love the look of the Australian blackwood |
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| Author: | J De Rocher [ Sat Nov 19, 2016 4:45 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Very nice! How big is it? How wide is the lower bout? It looks like a lot of work went into the saddle. Regarding the A-frame braces, were they actually let in to the heel block, or were they butted to the heel block? |
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| Author: | Pmaj7 [ Sat Nov 19, 2016 4:53 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Nizzze! |
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| Author: | Glen H [ Sat Nov 19, 2016 5:37 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Incredible! |
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| Author: | Freeman [ Sat Nov 19, 2016 10:03 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Beautiful guitar, Steve. How do you like the smaller body? Are you tuning to concert? Any significant changes to bracing in the lower bout? Fwiw, when I built my OM 12 I just followed Taylors lead and bumped the top thickness from my usual 0.110 to 0.125 (but I also tune down). My old Martin 12 is 0.115 and has developed a bit of a belly. |
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| Author: | meddlingfool [ Sat Nov 19, 2016 10:43 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Very nice! |
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| Author: | SteveSmith [ Sun Nov 20, 2016 5:39 am ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
It looks great. I have a nice set of blackwood and seeing yours makes me want to build with it. |
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| Author: | WaddyThomson [ Sun Nov 20, 2016 11:19 am ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Wow! That's beautiful! |
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| Author: | Colin North [ Sun Nov 20, 2016 1:40 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
A touch of class there Steve. EIR FB too? What's the scale length? Be nice to see one pic of the whole guitar |
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| Author: | SteveT [ Sun Nov 20, 2016 2:59 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Thanks for the kind words & interest! Answers to questions: J De Rocher The overall length is ~41" with a lower-bout width of 15". The A-frame braces are glued into ~1.5" long channels in the heel block. I used Liutaio Mottola's "Fretted Bridge Saddle Compensation Calculator" http://www.liutaiomottola.com/formulae/compensation.htm to do the saddle compensation. Mottolo's calculator is set up to deal with 12-strings (or any number). Worked well & was easier than using the approach of putting a wire under each string & adjusting to set string length. Freeman The guitar is tuned to concert pitch, but I am using extra-light strings right now. The lower-bout bracing was also beefed up a bit. The X-brace is 0.35" wide, 0.65" high, triangular profile, no scalloping. Colin North wrote: A touch of class there Steve. EIR FB too? What's the scale length? Be nice to see one pic of the whole guitar The fretboard is ebony. I thought of using same materials for FB & bridge (either ebony or EIR), but I liked the look my classicals that use ebony FB with EIR bridge. Scale length is a short scale 24.9" |
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| Author: | Quine [ Mon Nov 21, 2016 11:19 am ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Nothing more impressive that a big slot-head 12string head stock |
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| Author: | Mike Collins [ Mon Nov 21, 2016 3:51 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
very well made & beeeeeaaaauuuutiful also! Mike |
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| Author: | J De Rocher [ Mon Nov 21, 2016 4:20 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
SteveT wrote: The A-frame braces are glued into ~1.5" long channels in the heel block. That's an interesting idea. I haven't seen that before, but like a lot of things, maybe it's have been done at some point in the past. I imagine it adds a significant amount of strength to that area. How do you make the channels? |
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| Author: | Terence Kennedy [ Mon Nov 21, 2016 4:54 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
Great miters on the end graft. What's your technique? Beautiful instrument, not something you see everyday. |
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| Author: | SteveT [ Mon Nov 21, 2016 7:40 pm ] |
| Post subject: | Re: 12-String Slot Head Triple-0 |
J De Rocher wrote: SteveT wrote: The A-frame braces are glued into ~1.5" long channels in the heel block. That's an interesting idea. I haven't seen that before, but like a lot of things, maybe it's have been done at some point in the past. I imagine it adds a significant amount of strength to that area. How do you make the channels? The A-frame is not an original idea with me. I learned about here on the OLF. The following link has some discussion & a nice pic from Buton LeGeyt. viewtopic.php?f=10101&t=45037&hilit=carruth+a+frame&start=25 Terence Kennedy wrote: Great miters on the end graft. What's your technique? Thanks for noticing. Until this guitar, I had never been able to get all 4 miters on my end grafts, usually getting 3 acceptable ones & one that I was not proud of. Cutting the purflings attached to the bindings has never been a problem. Just used a small (~1.5 mm) chisel with a mirror-polished back. For the purflings on the end graft proper, I never had complete control of cutting miters using a chisel and the polished-mirror trick. (The purflings are glued to the end graft & installed as a unit.) For this guitar (oh, the shame of not using an edge tool  ), I used my disc sander with a 45-deg fence & my binocular magnifier visor to see close up: Perfect control to get the miter at 45-deg & no wandering through the depth. Getting a perfectly vertical cut with a chisel was always a problem. Guess I should have built a jig. I recently saw that Stew-Mac has a drill press mounted binding cutter that might solve that problem.
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