francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 18, 2016 18:33:33 GMT
Few photos of the (almost) completed instrument - just a truss rod cover to do now and buff the wax finish... Had to change the tailpiece as the slotted front allowed the string loading to bend the whole thing upwards. Replaced with an ebony block having paired holes for the strings to go through and act as guides. Francis
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 17, 2016 15:44:25 GMT
Designing and making things using a "scientific method" usually involves a definition of the objective end goal that is uniquely accepted, and can be accurately measured to the extent that you know if you achieved it and if not precisely how far away you were. I have yet to see such a definition for an acoustic guitar. The "scientific theory" provides a complete understanding of how everything works and guides you along the way. With an instrument made from organic materials and played by organic beings with all of that subtlety and variation this is hardly surprising. Also you are in the world of subjectivity rather than objectivity when it comes to assessing "playability", "response" and "tone". In cases like this what tends to happen is that nuggets of "science theory" get quoted - cube rule of stiffness, strength to weight, dipole/monopole, Youngs Modulus - and measurements of things that can be measured are taken. This can become the cliche of looking for your lost car keys at night under the street light. By all means read and research all of the scientific theories of guitar making, but remember not to believe everything you read on the internet - including this There are more people on the internet that make guitars in their heads rather than with their hands. The best way forward in my view is to try and have a clear view in your own head about what it is you want to achieve when you try different things and how you will know if you have done it. Then just make them. Trust your hands, ears and eyes rather than theories you don't really understand. I'm fortunate that I came to making as a player so I know what I'm aiming for and when I play my finished instruments how well I'm doing - I'm making for me the player. Thanks Dave / Rob, I think that sums up what I try to do at present although I wouldn't call myself anything like 'a guitarist'. My problem is I've worked in technical, research and forensic fields for pretty well my entire working life and it's very difficult to get out of that precision mind-set into a dare I say 'sensual one'. I thoroughly enjoy the changes in sound as I work timbers for my guitars, always endeavouring to get the best from a multitude of different materials available. But always having this nagging feeling as I work that things are not quite the same with this build as the last or the one before that. Hence this feeling that I need to build-in consistency using some form of measurement. Perhaps if I build completely different guitars each time so the current build is not like the last, therefore gut feeling is the only way forward... Francis
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 16, 2016 13:48:28 GMT
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 16, 2016 10:26:14 GMT
Should I…?
My next guitar build is quite a departure (for me) in terms of bracing, side construction and fret arrangements (i.e. moving from orthogonal to multi-scale), do I need to look more closely at how I ‘tune’ the different components?
Reading Siminoff’s book on tap tuning seems (to me) an extreme in tuning every component with a meter prior to assembly. I tend to look a stiffness/flex of components prior to construction then move to ‘taping’ to achieve a clean sound with good sustain. But should I be metering the assembled front/back plates to particular notes? I usually make backs stiffer than fronts and make their tap tone ‘different’ to the front to avoid wolff notes. Not very scientific but it seems to have worked so far.
Do others meter their parts and at what stages?
What sort of analysers do people use to monitor tap tones ?
I’m really looking for a degree of consistency across my guitars and wondering if quantifying component stiffness alone is the best approach.
Many thanks Francis
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 14, 2016 6:55:14 GMT
Francis, you don't need to laminate the sides to make them stiff, the easiest way is to just use laminated linings. These form engineered structures that stiffen the sides without adding the extra weight. The only real function of the sides is to hold the back and top apart. The problem with laminated sides is they really need to be made using vacuum to ensure no gaps over the area of the sides. As you probably know I use laminated linings and have done so on more than 80 guitars now and once installed the mould can be completely dispensed with as the sides are now stiff enough to take the pressure from 30 or so go-bars without any movement. Colin Thanks Colin, I've made linings using mahogany laminations in the past but these have been kept very much to the sizes of standard kerfed linings. Yes they do keep the sides in-shape when removed from the mould. They also make the guitars interior look much neater. I guess what I'm 'seeing' from the different articles/blogs/websites dealing with laminated sides is that they don't absorb (read - minimal) any of the energy from either the front or back plates and being a solid structure in themselves means that bracing the top and back can be a more minimal affair because sides won't distort under string loading. I take your point about ensuring no gaps in the laminations when building the sides. I've used a vacuum to laminate veneer layers on the front and back plates of a couple of guitars where I wanted an archtop without the carving. These being relatively flat weren't too much trouble but I can foresee the sides being a little more problematic. My thoughts at present are on the lines that I need to build a guitar with solid sides to see if it does effect the sound in the way others are finding at the expense of a heavier instrument...
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 11, 2016 21:24:04 GMT
Thanks Guy's - postage is expensive though!
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 11, 2016 15:40:43 GMT
Where are people getting their fish glues from in the UK? Francis
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 10, 2016 15:12:12 GMT
Thanks Kym, The curved bracing very reminiscent of Gary Southwell model A soundboard bracing although I don't think Gary uses carbon on the braces (they're also far more delicate as it's on a classical model) but uses CF rods within the body.
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 10, 2016 11:07:42 GMT
This is where I am with my thinking at the moment with reference to the body shape, side laminations and bracing of the top. Body shape is fairly traditional Triple 'O' with cutaway: Body length 492, lower bout 382, upper bout 288. Asymmetric X brace. Soundboard: Western Red Ceder Back Cherry Sides (outer - cherry) laminations 2x (tulipwood or Sapele) Soundboard bracing: X-braces 16 x 7mm spruce with central, vertical hardwood lamination Other soundboard braces spruce. Linings - none front/back direct bonding to sides. Welcome comments on this
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 10, 2016 10:42:57 GMT
This is great - thank you.
This was asked as I'm looking to build a triple O fan fretted guitar with stiffer sides but really knowing very little about them. Reading the Gore/Gilet book review was very interesting - anyone got a copy they want to sell?
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 10, 2016 9:31:29 GMT
Mine is a 9th fret I think. You don't need a great length of the bass to tighten everything up. The major factor in the angle is the length of the 1st string? My 1st never goes higher than D so I stuck with an OM scale length. Others prefer a shorter scale on that string which presumably exaggerates the angle. I've based mine on a Triple 'O' with a short scale of 632mm, An OM typically is 645mm, it's the difference in the scale lengths relative to the fretboard width that creates the total angle - how that angle is distributed is down to the position of the null fret. Placed at the 12th fret the angles are equal either side, moving the null towards the nut increases the angle at the bridge or vis versa. I'm looking at a 55mm fretboard width at the 12th fret with a 25mm difference in the scale lengths that gives me a total angle of: 24.44° with my scale length of 632 that gives me a treble side pivot point for the fret fan at 1459 mm or 1431 mm from the fretboard centre line. Making the fretboard wider increases the pivot point distance, a narrower fretboard has the opposite effect.
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 9, 2016 10:47:28 GMT
This looks really elegant Francis - would love to see a pic on the underside too....? And even though I wouldn't be using the bridge as a vibrato arm (well, not very often anyway ) I still reckon the yew corners are a bit sharp and liable to snag on clothing (no, I don't play with the strings towards me!) etc or a stray finger or cloth when taking instrument from / putting away in case - if it were mine I'd be taking a bit of abrasive paper to the corners just to ever so slightly round them off. I bet this looks terrific on the instrument! Keith Your wish is my command... Similar slots along the back edge but that is at about 45° to keep the strings in position - just about make out the slots in the felt
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 9, 2016 8:23:09 GMT
Bringing this one to a close now. Changed to tail piece as I didn't like the bought one and have made a brass and yew one more in keeping with the instrument itself... The red is a self-adhesive felt placed on the underside to prevent string vibrating in the metal guides. The tailpiece now takes ball end strings rather than the looped ones. I've also ordered some heavier gauge strings after the cautious ones used to start with.
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 9, 2016 7:57:38 GMT
I asked a question on laminated ribs/sides in another thread on here and got an interesting response from Nigel. Whilst he's not giving away the material he now uses he's piqued my interest enough to use laminated sides on this one. Something else I've been thinking about but never got round to is laminated bracing making them stiffer and lighter, certainly for the main spars. (I also have some Nomex bought years ago but that can wait for another time and place). TBC...
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francis
C.O.G.
Posts: 2,405
My main instrument is: Whatever I'm building...
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Post by francis on May 9, 2016 7:21:15 GMT
Superb build Rosie, Love the choices of timbers on this one - internal as well as the external. Looking forward to completion and the sound.
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