#16
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---- Ned Milburn NSDCC Master Artisan Dartmouth, Nova Scotia |
#17
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I do Fender saddles by getting the 1st and 6th strings right, then eyeballing the rest. - it includes looking across the strings at the bridge to see the evenness of curvature; any irregularities are very obvious. Acoustic saddles seem to be just simple geometry to me on a fixed-radius board with properly leveled frets, and I can't see any reason why the saddle shouldn't have the same radius as the board, or strictly speaking, the fret crowns. Assuming the 1st and 6th strings are where you want them, then: Having a greater saddle radius will make barres more difficult than they need to be, and Having a shallower radius could lead to fret rattles on the inner strings. So I get the radius right, then remove stock from the bottom of the saddle to get the bass and treble height right. - I use the vise jaws as a stop to get most of it off, then finish it by rubbing on a flat (they sometimes aren't) file. If I'm missing something here, I would be glad to know it for future reference. FWIW, my saddle radiusing jig consist of a stiff flexible strip - I use a power hacksaw blade - with coarse sandpaper stuck to one side. I clamp one end to the bench, sandpaper side up, then use a wood block to ramp up the free end until it is the correct concave for the saddle radius, as measured with the old saddle, or (homemade) concave and convex radius gauges. Then it is just a case of scrubbing the top of the saddle on the sandpaper until it is radiused. I do intonation by having one front-to-back slant for the first two strings and another for the other four.
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Tony D http://www.soundclick.com/bands/defa...?bandID=784456 http://www.flickr.com/photos/done_family/ |
#18
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#19
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If this has been discussed before, do you have a link please. I'm genuinely interested to know the arguments surrounding this.
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Tony D http://www.soundclick.com/bands/defa...?bandID=784456 http://www.flickr.com/photos/done_family/ |
#20
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Any way you achieve that is fine. I just don't do it by trying to relate the radii of two curves. To achieve the graduated heights you describe, the radius of the top of the saddle cannot be the same radius as the fingerboard. Generally, the curvature of a fingerboard is the surface of a cone, rather than a single radius cylinder. With a conic, which radius are you trying to match? The radius at the first fret? The 12th fret?... The further up the fingerboard you go, the larger the radius. By the time you project that to the saddle location, it is larger still. And, that doesn't account for the graduated string heights. Those are achieved by "tilting" one radius relative to another. It's geometry. Quote:
The Stratocaster bridge is a good model. There are 6 individual saddles. Each is adjusted until it produces the desired string height. No thought is given to any radius. They form 6 independent, steps. If you eliminate the height adjustment from each of the Strat's saddles, glue them together side-to-side, you have an acoustic guitar saddle. You have one saddle with 6 individual, discrete steps in its height. There is no curvature. Each of the 6 steps provides the string height desired for the individual string it supports. There is no curvature. There is no radius. There is no spoon - oops, got carried away. The 6 points of intersection between each string and where it crosses the saddle can be joined by a smooth curve (i.e. Bezier). It won't be a curve of a constant radius, but, rather one of multiple radii. Can that be approximated by a single radius curve, sure, if you want to. I see no need to. Here's what one of my saddles typically looks like: Here's what happens with the break points for a fully compensated saddle: Last edited by charles Tauber; 01-29-2014 at 04:59 PM. |
#21
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I've always thought of boards and saddles as cylinders, eg 15" all the way, except for compound radius boards which I would treat as a cone. However, it isn't as easy as that because if you were going to very small tolerances, the difference in string width between the nut and saddle - the string aren't running parallel to the cylinder. That would also have an effect on how I would treat the saddle curvature if I could get my head around the geometry of it.
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Tony D http://www.soundclick.com/bands/defa...?bandID=784456 http://www.flickr.com/photos/done_family/ |
#22
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All good! Must'a'been just the way we was talkin' was makin' us sound like we was sayin' diff'rent things, but we was actually sayin' the same thing. ;-)
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---- Ned Milburn NSDCC Master Artisan Dartmouth, Nova Scotia |
#23
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On more reason that I use the "top down" approach is that much of my tinkering is applied to old Martins and Gibsons with long, glued-in saddles. Lowering from the bottom is not an option, since the wings would no longer match the bridge. I've done so many from the top that it just seems the more natural thing to me now, and it gives me complete control of individual string height as Charles described.
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#24
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And, that's my point. You don't have to. Use the height of each individual string to tell you what the saddle contour should be.
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#25
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It seems this thread is in some real good company of luthiers, awesome.
With the consideration that the slot for each string at the nut is filed and cut-to-depth individually based on it's relative height to the first fret (this is correct right?), my question is, why isn't the saddle made in exactly the same way? Some eluded to shaving the saddle and compensating it individually, but my question takes it a step further: why don't luthiers file slots in the saddle for the strings like what is done at the nut? |
#26
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Tony D http://www.soundclick.com/bands/defa...?bandID=784456 http://www.flickr.com/photos/done_family/ |
#27
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Wow, what a bargain...I asked for Saddles 101 info but ended up getting the full Ph D. dissertation! Thanks again all!! But it will take me some time to digest it all, that's for sure. Why can't acoustic saddles be like electric saddles? No sanding or filing needed there, just an allen wrench and a screwdriver and you have infinite adjustment at your disposal. I think I recently saw an acoustic guitar (probably on ebay) with an electric type bridge, but can't remember what it was.
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John ------------------------- Alvarez Yairi DY 57 1978 Yamaha FG-110 Yamaha FG-160 Yamaha FG-180 Yamaha FG-800 Fender partscaster Fender MIM Jazz Bass Five old dead basses awaiting resuscitation |
#28
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---- Ned Milburn NSDCC Master Artisan Dartmouth, Nova Scotia |
#29
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The biggest issue with most adjustable systems is weight, as in too much compared to a simple piece of bone in a slot.
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#30
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At the bridge end, the distance to the anchor point (the bridgepin) is small enough that slotting the saddle is unnecessary, and since it frequently causes problems, it is seldom done. Archtops with tailpieces are a different story, some builders do slot the saddle on archtops.(Not usually as deeply as the nut is slotted)
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Rodger Knox, PE 1917 Martin 0-28 1956 Gibson J-50 et al |