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Post by Michael Messer on Aug 12, 2007 12:04:20 GMT
There is no evidence or documentation stating that National & Dobro used laminates/plywood for reasons of economy. They were built that way to get the tone they were looking for. The 'speaker cabinet' construction is probably not the best description, but a wood-bodied National Triolian is far closer in construction to a speaker cabinet than it is to an acoustic guitar. The quality & thickness of the laminates is an absolute essential ingredient to getting the tone correct. As a general rule (and there are always exceptions to rules), National style single cone & Tricone instruments should be built from laminates, not from solid wood. Dobro spider-bridge guitars are different and both laminates & solid tone-woods were used to make great guitars. My personal preference in Dobro spider-bridge guitars is laminate/plywood. Mike Lewis at Fine Resophonic Guitars makes his own laminates and spent many years researching and testing materials until he got what he considers to be similar laminates to what National & Dobro used in the 1920s.
Shine On, Michael
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Post by franklin on Aug 12, 2007 13:27:05 GMT
Thanks tark, thanks Pete, you guys are great, I've been busy making my mold and hollow forms, since the shape is about the only thing I know for sure.
I have a fairly good understanding of the construction of a traditional Dobro simply because there seems to be more information available than there is on the biscuit bridge resonator. I have never run across a photo that shows the inner construction on these instruments as clearly as Pete's photo of the Dobro, come on Pete, dig deeper.
Pete isn't the only gentleman that I have run across that uses a separate stick attached to the neck and tail blocks to support the sound well. His was a bolt on, while Pete's is a dovetail. I suppose I felt the neck stick attached to the neck was a means to help support the neck, do I have this all wrong? Obviously if Pete is using a standard dovetail the extra strain that heavier strings and open tunings might put on a neck aren't an issue. If this is true what is the function of the neck with a stick, and does it have any advantages over other means of attachment.
Gotta go for now , but thanks to both of you, keep it up.
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Post by Blues Pertti on Aug 12, 2007 13:38:45 GMT
Hi, It's a pleasure to make a resonator guitar. In mind you can get surprisingly pleasing results even with Finnish birch ply construction. There is some thread ("It is not a Triolian...") where is some pics about finished guitar. Regards Pertti
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Post by franklin on Aug 13, 2007 1:07:08 GMT
Thanks so very much Michael Messer, I was relatively certain that since my interest are in a National style instrument, I would use laminates, and your information kinda settles that aspect for me.
I do have the ability to lay up laminates using vacuum, they will look good, but I'm afraid their tonal qualities are completely out of my area of expertise. I realize, as you have stated, good tone comes from years of trail and error.
Since you mentioned thickness, and and the role it plays, and at the risk of becoming a pain in your neck, I was hoping you might suggest some parameters I might use for starters in regards to the thickness of the tops, backs, and sides, at least what might have been normal for a 1920's National.
I understand your very busy and I appreciate your previous response, any additional information you could send my way would be received graciously.
Thanks again, Franklin
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Post by LouisianaGrey on Aug 13, 2007 8:33:58 GMT
I prefer the sound of solid woods but then I'm not trying to reproduce the sound of old Nationals or Dobros when I build. If I was then I'd probably go the laminate route. I wasn't aware that Mike Lewis didn't use solid woods as the wood on every one of his guitars I've seen looks so beautiful.
As far as the neck joint goes, I like to use a neck stick but I can't see any reason why it has to be attached to the neck in a wooden body. In a metal body it is necessary because it's the easiest way to get a rigid line between the tail and the headstock - the metal body on its own would probably fold up. It's essentially banjo technology, and done for the same reason. Don't forget that wood has grain that (if it's solid wood) runs from neck to tail so it's very stiff in that direction. Laminate is also stiff, whereas metal will bend in any direction.
I think the function of the neck supports ("mushrooms") under the neck stick on a biscuit bridge metal body is to stop the back flexing so I don't use them for a wooden body, I think the stick gives sufficient rigidity to the neck/top/soundwell structure. On a spider bridge without a conventional soundwell the top is braced against the back by the support posts - that photo wasn't one of mine, incidentally, and I normally have the support posts resing on flat-topped back braces. The best information on the net about how to build a support-post dobro (squareneck, but much of it is the same as a roundneck) is Gary Dusina's set of articles at reso-nation.org
I use bolt-on necks on spider bridge but dovetail necks on biscuit bridge because of the difficulty of getting at the neck bolts with the soundwell and neck stick in place (I like to make the neck and body separately and then bring them together. Otherwise I'd have to bolt the neck on before I glue the back on).
As for neck strain, bear in mind that a resophonic string set isn't much different from a heavy acoustic guitar set - it's pretty much only the two plain strings that are heavier than a regular set of .013s would be - and other than high bass G on squarenecks the open tunings are usually tuned down from standard so I don't really think it's an issue.
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Post by Michael Messer on Aug 13, 2007 8:57:25 GMT
Hi Franklin,
I do not know the actual measurement of wood thicknesses in a wood-bodied Triolian. I am sure there are forum members who can help you in this area. As I said before, the choice of wood in the laminate is absolutely crucial to the whole thing. I do know what Mike Lewis uses, but he is quite secretive about his materials and construction methods, so I cannot talk about that. It may sound stupid, but I understand, Mike spent years researching & developing his guitars before letting us play them.
Good luck with your project - keep us posted and fel free to ask questions and post photos.
Shine On Michael.
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Post by Mark Makin on Aug 13, 2007 10:13:04 GMT
Hello Franklin 1928/9 wood triolians have a body top of just a fraction over 5mm thick laminate but less than a 1/4 inch in old money. Other wood bodies, Trojans etc are less than that
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Post by franklin on Aug 14, 2007 1:27:42 GMT
Thank you Mark, 5mm confirms what I suspected for the top. I've run across various photographs of wood bodies lined up in the National factory, and Michaels instructional DVD shows some pretty clear shots of the f-holes on his Fine Resophonic, couldn't help peeking, Michael.
Now lets work on the back and sides. The same photographs, though from a distance, suggest Nationals have no bracing on the backs, can anyone clear this up for me? If so this leads me to believe the back may be as heavy as the front. My thoughts were to lay up a laminate formed with a radius for the back.
I would think the sides would be somewhat thinner, but that's just a guess.
If anyone knows anyone who has sat on their 1928 Triolian please measure the back and sides. Thanks so much.
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Post by Mark Makin on Aug 14, 2007 9:37:17 GMT
Hi Franklin While I've got my ruler out!!!! Back is same thickness and is, incidentally, perfectly flat, no radius. Body depth is 2.11/16 at the neck heel (70mm) 3.3/8" at the tailpiece (86mm) Some instruments are known that are 75 and 91mm . Two internal braces on the back plate (X or converging parallel - your choice!) are 18mm x 10mm deep. Anything else and I'd have to break it apart! OK?
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Post by tark on Aug 14, 2007 12:52:46 GMT
Hi Franklin,
My experiments with metal bodied guitars and discussions on this and other forums suggest that getting the back right may have a large effect on tone. With a very stiff thick back you may find your guitar lacking in bass. This is a bit like putting a loudspeaker in a cabinet that is acoustically too small for it.
Notice that the body depth of these guitars is quite shallow compared to todays conventional acoustics and even with the extra volume afforded by the long 12 fret body there seems to be insufficient volume inside the body to produce sufficient bass unless the back is allowed to be quite flexible to lower the main body resonance.
It's just struck me that an alternative approach, to follow the loudspeaker cabinet analogy, would be to build the body with a rigid back, but fit a tube instead of conventional sound holes. The bass response could then be adjusted after construction was mostly finished by tuning the length of the tube. Some luthiers have experimented with variable soundholes or ports, but I'm not convinced they fully understood the principles involved. The only example I know of anyone using a tube is the great Spanish guitar maker, Torres. He called it a Tornavoz. None of the commentators on his work seem to understand what it was for, or how it worked.
Incidentally I have noticed that the old style National body shape is very comfortable due to the shallow depth and slightly narrower elongated outline.
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Post by 1928triolian on Aug 14, 2007 13:47:13 GMT
Hi Mark Makin,
don't know if it's a right thought, but I'm wondering if in wood body Triolians parallel or X back bracings are really equivalent.
In Trios with parallel back bracings there are two "mushrooms", at 12 and 6 of the well; meanwhile in X back braced Trios we find only one mushroom toward the tailpiece, and sometimes I've seen a front wood support inserted between the neckstick and the crossing of the bracings. My flowers decal, as an example, is X braced but has not the wood front support.
Could these have been all different constructive ideas, as these guitars were all protoypes?
thank you
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Post by frankin cash on Aug 14, 2007 19:30:04 GMT
You cats sure know your Triolians, now were getting somewhere.
Mark, would I be correct in assuming that back is perfectly flat, and the difference in body depth from tail to neck, happens on the front, north of the bridge, or 12:00 at the sound well? I picture it as a break angle coming off the bridge toward the neck. In other words most of the lower bout is holds at 3 3/8", then it begins to taper through the waste, and continues to decrease to the neck.
1928triolian answered my question regarding the mushroom supports under the neck stick, they used them on wood bodies then, and I understand they still use them on new Nationals.
Tark, maybe down the road I'll look at other possibilities, in regards to size or depth, but I think for now I'll stay on task . You may be able to improve the bass, but as you said they sure are comfortable to play.
As always, thanks to all, and keep em' coming.
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Post by Mark Makin on Aug 14, 2007 20:03:38 GMT
Franklin The top and the back are perfectly flat but are angled towards each other like a wedge. There does not appear to be a drop from a parallel body to a wedge half way up as you get on metal 12 frets. 1928triolian is correct IMHO to assume that the number of variants are because of the prototype nature of this instrument. Most of the discoveries necessary for metal bodies seem to have been worked on here. As I mentioned earlier , not only are there a great variety of X bracings, parallel bracings and variable post supports but the thickness of the instruments also vary. We have been recently observing some of these instruments turning up with natural wood finishes as well and some have even turned up, like 1863W, listed in the late 1930 metal body triolian sequence and painted walnut sunburst to fit in to the metal triolian line. National still seemed to produce these things or at least have some hanging around to maybe fulfill orders if they hadn't the numbers in stock!!!! who knows?
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Post by Blues Pertti on Aug 16, 2007 15:36:32 GMT
Hi Pete,
Do you let us use similar structure in our project guitars as you have shown to us?
Regards Pertti
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Post by franklin on Aug 16, 2007 18:35:47 GMT
Thanks Mark,
I'm pretty sure that new wood Nationals taper the way I described, I assumed the 1928 did as well. Appreciate your patience with me.
Incidentally, I'm also pretty certain the new wood Nationals have no bracing on the backs, just the mushrooms extending to the back from the neck stick.
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