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Thread: Bridge 101

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    I'm not a builder but I've been doing some tinkering with my mandolin and I need some educated advice. The neck angle on my Fender A is so steep that I get a buzz on the high frets even at the highest setting on the factory bridge. Short of changing the neck (major surgery; no truss rod) I've decided to fashion my own, slightly higher, solid bridge out of stock maple. How thick should this new piece be? Does a solid base versus two or three feet make a difference in response? Anything else I should worry about? Sorry about the generic nature of the questions, but I really am brand new at this. Thanks in advance.

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    Mando-Accumulator Jim Garber's Avatar
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    Lots of info and bridges for sale here.

    Jim
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    Café habitué Paul Hostetter's Avatar
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    Good for you, to have the inclination to try something like this. Since you'll probably want to try more than one, try a second one using ebony or equivalent. The damping qualities of different woods are as important than the dimensions. Well, almost.

    If you look at a typical early Gibson A, you see those bridges were fashioned from stock that was about 1/4" thick, and that allowed for adequate compensation of all four courses. You want this to play in tune, right? So you could start that thin. Most adjustable bridges have a bigger footprint, so you could also start with that as a base and gently narrow the stock to the top where the strings meet wood.

    The bridge is a brace. The length of it serves both structural and tonal functions, and you probably don't want to go less than 4". You probably don't want to make the "wings" too thin, lest the bridge flex too much. Distribute the pressure and the string signal across the top.

    I usually start with a rough blank and make the base a vacuum fit to the belly of the instrument, then draw on the blank exactly where the strings need to be, leaving that a little high, and then draw the outline and start working it down to the final size and shape.

    Another approach might be to make a new taller top for the adjustable bridge you now have, and just continue to use that base.
    .
    ph

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    Quote Originally Posted by
    Another approach might be to make a new taller top for the adjustable bridge you now have, and just continue to use that base.
    My thought exactly. I just wish I had the same problem; action on both my mandos was too low. So far I've used delrin, rosewood, ebony and bone. For me, the hardest part (aside from "luthier's grade" work) is getting the post holes exactly located.

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    Café habitué Paul Hostetter's Avatar
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    Got drill press? Measure twice, cut once.

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    Quote Originally Posted by (Paul Hostetter @ Feb. 07 2007, 12:49)
    Got drill press? Measure twice, cut once.
    Exactly.

    What's the right way to word that so that the implication is that it isn't all that hard?

    To be brutally candid, the hardest part for me is to slow the frell down and do the job right, but no; do I clamp the part in the vice and rough it out with the back saw? "Well, the bandsaw's right here... OOPS!"

    It seems I spend more time fixing things that wouldn't need fixing if I'd just do it right the first time. At least, that's what I do for my clients and employers.

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    Café habitué Paul Hostetter's Avatar
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    If you start with a fairly tidy rectangle of wood, mark the two points, and use a bradpoint bit of the right diameter, the drillpress will put two parallel holes right where you wanted them. You don't need a drillpress vise, but you might need a temporary fence clamped to the table so the holes align the same distance from the edge of the little block you are starting with. It's not hard. You just have to be methodical.
    .
    ph

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    Thumbs up

    Thanks for all the great advice. As soon as the weather warms up I'll head out to the shop and start playing with some designs.
    TMitchell

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    Google ... Red Henry.
    Lots of good information and instructions.

    Curt

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    Mando-Accumulator Jim Garber's Avatar
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    Quote Originally Posted by (mythicfish @ Feb. 08 2007, 15:43)
    Google ... Red Henry.
    Lots of good information and instructions.

    Curt
    Sorry, Curt... that was the link I posted in the second post.

    Jim
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    Some good info on making a solid bridge here. I made one for an A style Rover and it made a big difference in volume.

    http://www.murphymethod.com/earlybridges.html

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    I have a piece of fossilized walrus ivory that I am thinking of using to make a bridge/saddle for one of my mandolins. Any input on how hard it is to work?

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    Café habitué Paul Hostetter's Avatar
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    It's not significantly different than bone. Try a piece of bone first and see if you like how it sounds before you commit the FI to it. A few people like FI for mandolin bridges, most find it too shrill and harsh. Depends on the instrument I suppose. Or the ears hearing it.
    .
    ph

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    Registered User Bill Snyder's Avatar
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    Three of ya'll (starting with Jim Garber) have suggested Red Henry (the Murphy Method link). You can also take a look at this bridge by Steve Tourtellotte.
    If you have any wood working skills (or if you don't but are patient and careful) you can make both the Red Henry style and the Tourtellotte style bridges. It can be fun and if you like the result you can tell people that you built/carved/fabricated/made (choose your verb) your own bridge.



    Bill Snyder

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    Café habitué Paul Hostetter's Avatar
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    The above-referenced shortened Tourtellotte bridge poses a rather serious problem for some mandolins: too much pressure over too small an area. Have had several A's through my shop recently with real issues over this - not with his bridges, per se, but short ones. The tops couldn't take it. The bridge is, among other things, a brace.
    .
    ph

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    Registered User Bill Snyder's Avatar
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    Paul that makes sense. I made a bridge similar to one of the old Red Henry designs a few years ago after reading how much they improved the tone of a mandolin. I can't really say that it helped much but it is on an inexpensive instrument and it is made of teak so I don't think that it was much of a test. It does sound at least as good as the original bridge.
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    Bill Snyder

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    Café habitué Paul Hostetter's Avatar
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    Teak is an interesting wood, I need to explore that one some more.
    .
    ph

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    Registered User RJinRI's Avatar
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    'made these this past weekend from the Red Henry design. mounted bridge is made from myrtle & the other from ebony.
    and yes, the shop was cold, so multiple trips back & forth were required.
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    Generic factory bridges aren't what they seem and replacing yours with a solid self made one will be rewarding and likely result in better tone, though it will take some experimenting.

    I very much like the idea of reducing the bridge mass, but I drill holes up from the bottom of the bridge rather than through, simply because I like the solid look with the hollow tone. If memory serves, Frank Ford has done the same. I've tried sculpting a concave impression in the sides of the otherwise solid bridge, but find it takes more time than a few holes at the drill press (and I'm basically lazy).

    Peace, Mooh.

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    A turner friend of mine (lathe/bowl maker) made a bowl out of sweetgum burl the other day and I was taken by how HARD (and beautiful, too) that wood was. It had a lovely fine grain that polished out smooth as ebony does with no finish. I think an experiment is in order.

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    Café habitué Paul Hostetter's Avatar
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    Which sweetgum? Besides the Australian ones, there is Liquidambar styraciflua – whence styrene, derived from a resin in the tree – known commonly as American sweetgum, which has cultivars wreaking havoc with lots of urban landscapes. It is native to eastern North America from New York to Texas, down into eastern Mexico to Guatemala. It’s a really messy tree that lifts sidewalks and sewer pipes at will. Unfortunately it's about all we get for fall color here in California

    It’s not a very likely candidate because it’s not hard, it’s just fine-grained, the heartwood being reddish and, when cut into planks, marked transversely with blackish belts; it is used for veneer and pulpwood, but is poor for timber or fuel. Being soft and absorbent, it is readily dyed, so it is sometimes used as a faux-ebony for picture frames, but it is too prone to decay for outdoor work and too soft for much else. Maybe the burl is different. Let me know where this particular tree grew, and how your experiment works out.
    .
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    Honestly, thats a good question. I question if it is actually sweetgum now because looking on line red sweetgum (Liquidambar styraciflua), which is probably what we'd have in western NC mountains, tends to be more akin to walnut color wise. This wood is VERY creamy white with an extremely fine texture. He just said it was sweetgum. I've seen that it's sometimes substituted for walnut in dulcimer manufacture. I'm wondering now exactly what this wood is and if maybe I misheard. This could be a case of the 'ironwood' phenomenon. There are a billion different kinds of ironwood around here. Or maybe the burl is different, who knows, but I'll have to check into it, because it was a great looking wood.




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    OK.. Determined I was mistaken in what he said it was. The wood is actually sourwood burl.

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    Check out this site I have bought three or four of his bridges that I put on imports and been talked into selling everyone of them.

    http://home.bellsouth.net/p....628&ck=
    Hobbit

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    Café habitué Paul Hostetter's Avatar
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    The Tourtelotte site was suggested already. What kind of imports, and why did you sell them? Or did you just sell the bridges?
    .
    ph

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