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PostPosted: Wed May 08, 2019 12:53 pm 
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Brazilian Rosewood
Brazilian Rosewood

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I have a client I am building two guitars for one a very small parlor the other an OM. He's given me license to build in my own style so the OM is not a Martin replica but he wants the vintage style Martin Pyramid bridge, on both. I've decided to make them an inch wide instead of 7/8ths since they are steel string guitars and might need a bit more foot print.

But anyway... My question is really this. What do you think of that bridge design? Especially in thinking of modern guitars. I think the design goes against a lot of the way I think the strings drive the top of the guitar. In particular the wings. The tip of the pyramid is bulbous and heavy and is further towards the outside edge of the wing and the side of the pyramid that faces the saddle is long and drawn out and even rounded over to where it meats the central block (for lack of a better word) of the bridge and is very thin and weak at that point.

So it's almost like the entirety of the bridge is the central block and then you just have these bulbous weights hanging out at each end.

Thoughts?


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PostPosted: Wed May 08, 2019 2:13 pm 
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Brazilian Rosewood
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That is the way I make them. And I use African blackwood.
I heard or read somewhere you can adjust the stiffness of the wings by altering the depth of the "trough" next to the central block. The center of that long sloping side of the pyramid can form somewhat of a spine to add stiffness to the wings (whose stiffness again could be modified by shaping). Like scalloped bracing there are theories proposed as to why it was done that way.
On the old parlor guitars the fretboards are flat and thinner than their modern counterparts. Consequently the bridges tend to be lower which reduces their mass some.
I like the look of the Martin style pyramid bridges better than the Chicago (Washburn) style. From a structural standpoint the belly bridge is a better design than either.
An interesting site that explores some of Martin's bridge designs:
http://vintagemartin.com/bridges.html


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PostPosted: Wed May 08, 2019 2:16 pm 
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Brazilian Rosewood
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The pyramid style with a glued through saddle never made much sense to me although it looks cool. I have always thought that on a small guitar a light bridge was better and have used BZ pretty much exclusively.

I don’t have any physics to back that up :). Putting all that mass on the ends of the wings just didn’t seem like a good idea.

Mine look like this. You can do a drop in saddle that looks like a through saddle but I never tried it.

Image

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PostPosted: Wed May 08, 2019 2:49 pm 
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Brazilian Rosewood
Brazilian Rosewood

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Yeah that's what I am doing in this case is making the wings stiffer. I was just up at the 'Pickers Supply' in Fredericksburg VA last weekend and that place is like a museum with all the vintage stuff they have for sale there. So I got a good look at some of those old Martin bridges and they are really thin in the trough. My plan is to make the edges of the trough thin but thicken it up in the middle.

I normally do something similar too, I call it the faux-thru saddle. It looks like it's through but it's not. But those old Martin ones are not all through saddle either. The ones I am replicated will be slotted.


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PostPosted: Wed May 08, 2019 3:27 pm 
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Koa
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There is really not that much excess material in the pyramid if compared to something like a classical bridge...if the pyramid is removed from the bridge, the underlying wing shape is that of a classical...the wing is radiused across the shorter dimension, with the amount of radius determining resistance of the wing to rotation versus the center section of the bridge, and the end bevel reduces mass where it is not needed.

This radiused trough is a detail we have seen missing in some luthier-made pyramid bridges, but is well covered in Mr. Ford's method of fabrication.

Rather than a hinge, it seems like the radiused trough detail provides an elegantly thin edge with an adequately stiff wing. The most recent pyramids done here were for some 42 Style guitars, where the BRW/adi 000 12 fret instrument got a nice, very old BRW pyramid...such a deep cocoa color that that both the fretboard and bridge can be mistaken for ebony.

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These users thanked the author Woodie G for the post: TimAllen (Sun May 12, 2019 12:40 pm)
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PostPosted: Wed May 08, 2019 3:53 pm 
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Brazilian Rosewood
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Here's Frank's article for those curious. That is more or less the way I did it too though I had not seen this articel yet.

http://www.frets.com/FretsPages/Luthier ... ridge.html

However one thing I don't get in Frank's tutorial is that the height of the tip of the pyramid is lower then the main body block of the bridge. I'm not sure how he achieved that with this method, unless maybe that particular Ivory one is the same height all round. The ones I had recently seen however were lower.


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PostPosted: Wed May 08, 2019 7:45 pm 
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Mahogany
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An acoustic guitar bridge certainly has characteristics of its own -- until it's glued to a soundboard backed by a bridgeplate. At that point it becomes an inseparable element in the stiffest and most massive brace south of the soundhole. In a composite bridge/soundboard/bridgeplate, the "hinge" of a pyramid bridge, while highly visible, is a structural nuance. Its total effective mass (which, of course, includes the mass of the bridge pins, the string balls, the saddle, and the mass of X-braces near the bridgeplate) is likely the main determinant of the "bridge" contribution to tone.



These users thanked the author Hans Mattes for the post: Clay S. (Wed May 08, 2019 7:56 pm)
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PostPosted: Thu May 09, 2019 7:55 am 
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Brazilian Rosewood
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"However one thing I don't get in Frank's tutorial is that the height of the tip of the pyramid is lower then the main body block of the bridge. I'm not sure how he achieved that with this method, unless maybe that particular Ivory one is the same height all round. The ones I had recently seen however were lower."

I do a few things different from Frank, so I can't speak for his results, but if the slope of the pyramid creates a "triangle" that is longer than half the width of the bridge blank, when the sides are filed at that same angle the slopes will "overlap" and that will lower the top of the pyramid.

One of the things I do differently from Frank, is making the "trough" or radius at the block. I tape two blanks together and use a brad point and drill press to make the initial cut and set the boundaries of the wings. Saves on filing.
I also use simple jigs to rough out the angles of the pyramid, first on the bandsaw and then on a 1"belt sander.
Working with Ivory, I'm sure Frank prefered handwork, so as not to get it hot - ivory is sensitive to heat.


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PostPosted: Thu May 09, 2019 12:16 pm 
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Clay

I am about to start a guitar with a faux-ivory pyramid bridge. Do you have more pictures of your method so I can see as many as possible before starting my first one?

Thanks

Ed


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PostPosted: Thu May 09, 2019 12:26 pm 
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Brazilian Rosewood
Brazilian Rosewood

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Hopefully Clay will chime in but if you want to get jiggy with it, check out this guys video.

https://www.youtube.com/watch?v=GyWy5bg5yFw


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PostPosted: Thu May 09, 2019 12:48 pm 
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Brazilian Rosewood
Brazilian Rosewood

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Hi Ed,
Here is one other picture that might help show how the jig works. As I mentioned after trimming the excess off with the bandsaw I then use the jigs with a 1X42 inch belt sander that smooths things off pretty well. With the beltsander I free hand the back of the pyramid as much as I dare, and then move on to shaping it with files and sandpaper.
I have some bridge blanks cut so I will try to do a couple and take some more pictures of the process. One thing I would recommend is making a couple out of less valuable material to see where the pitfalls lie. I hope to come by next week for the strips so if you would like to use the jigs I will bring them along. There was a discussion not too long ago on bridge making where other people showed other methods and jigs.


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PostPosted: Thu May 09, 2019 4:11 pm 
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Koa
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One thing we have opted for with our version of the 000 12 fret was to move the saddle slot back an additional 0.040", doubling resistance to slot failure for through saddles. We've seen a number of bridge failures on both vintage and custom built instruments, and one common thread running through those failures is inadequate support for the saddle. It's worth considering moving the saddle slot back from the 0.130"-0.140" range seen in some vintage bridges to closer to 0.180" if the saddle will sit in the 0.140"-0.160" above bridge range.

Attachment:
IMG_20190121_170703.jpg


Attachment:
IMG_20190121_170618.jpg


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These users thanked the author Woodie G for the post: Clinchriver (Thu May 09, 2019 5:18 pm)
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PostPosted: Thu May 09, 2019 4:30 pm 
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Brazilian Rosewood
Brazilian Rosewood

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I took some more pictures to hopefully fill in the blanks. The pictures are "posed" so the bridge blank is not always the same. The first picture shows two blanks taped together and the center of the trough marked for drilling.
The second picture shows the way I clamp the two blanks together (not relying on the tape) and centering the drill on the top edge of each. The next picture shows the blank after drilling. At this point the blank is taken to the band saw and using the jigs previously posted the pyramids are roughed out.
The final picture of this post shows the same jig being set up on an old delta 1 X 42 inch belt sander and the pyramid side being sanded smooth.


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PostPosted: Thu May 09, 2019 4:44 pm 
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Brazilian Rosewood
Brazilian Rosewood

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The next picture will show the other jig being used to smooth the end. If you want your bridges to look like the one in the video previously posted you can sand and polish the bridge as it is now shaped. If you want a copy of the Martin style then the back of the pyramid needs to be shaped. To do this I first use the little belt sander to remove some of the material on the trough side of the pyramid. I do this by holding it in hand rather than using a jig. I don't try to get it to final form but only remove what I know will be excess. The final shaping is done with files and sandpaper.


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PostPosted: Thu May 09, 2019 5:05 pm 
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Clay S. wrote:
That is the way I make them. And I use African blackwood. ……………………….) style. From a structural standpoint the belly bridge is a better design than either.
An interesting site that explores some of Martin's bridge designs:
http://vintagemartin.com/bridges.html

Thanks for the link, fascinating.

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PostPosted: Thu May 09, 2019 5:10 pm 
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Brazilian Rosewood
Brazilian Rosewood

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No matter what method you use it doesn't hurt to test the set up out on scrap before commiting the real work piece to it.

As a side note - the above bridges were about an eighth inch wider and a quarter of an inch shorter than the originals. I couldn't shorten the center section so the pyramids look a little "stubby". When they are finish shaped and sanded and mounted on a parlor guitar they don't look too bad.


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PostPosted: Sat May 11, 2019 3:58 pm 
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Cocobolo
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Clay S. wrote:
When they are finish shaped and sanded and mounted on a parlor guitar they don't look too bad.

???


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PostPosted: Sun May 12, 2019 10:03 am 
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Brazilian Rosewood
Brazilian Rosewood

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Hi Andy,
???
If you have a question or comment don't be afraid to post it, I don't take offense easily, sometimes even when it is intended.
Obviously none of the pictured bridges are in their final finished form. On a smaller bodied guitar the missing 1/8 inch on each wing doesn't make them appear too short, and the 1/8th inch added width gives them a little more foot print. With Parlor guitars using steel strings these days, it doesn't hurt to make the bridge a little wider, even if there is a slight loss of aesthetics.


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PostPosted: Sun May 12, 2019 10:54 am 
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Koa
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It seems as though Mr. B might have been seeking a photo of the finished project.

To further address the OP's question, it seem to me that the Martin-style bridge is distinctly feminine in nature, with very refined shapes that eschew both bulk and excess weight. Indeed, our BRW examples come in at 18-20g, Gabon ebony at 25-28g, and ABW at 30g.

One of the better sources for shape and proportion information is Mr. T.J. Thompson's site, which has some very nice shots of vintage-correct bridges. As can be seen, his repro pyramid bridges are quite svelte, and have lovely shaping.

https://proluthiertools.com/product/mod ... id-bridge/

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PostPosted: Wed May 15, 2019 8:50 am 
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Brazilian Rosewood
Brazilian Rosewood

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Update.

This is the one I am modeling the bridge after. It's an 1870 Martin. Notice the knife thin edge of the wings. It seems Marin had several iterations of this design over time and I'm wondering if most of the finish sanding was done by hand so a lot of them look so different. But anyway I didn't realize how difficult this was going to be.

Note too that this one is not through saddle. That is the way I am doing mine as well.
Image

I start making the trough with a round rasp file and make the outer face of the pyramid first.
Image

Then make the two side facets sloping down to the trough with a peak centerline right down the middle of the wing:
Image

This is the tricky part. It seems like it's a cone shape that goes from the tip of the pyramid down to both edges of the trough:
Image

Yet it still maintains a peak-ish sort of line that is rounded over:
Image

Frank Ford's trick of using sandpaper on a 6in ruller is a great tip. But still this is a really weird shape to get your head around.

It's gettin' there!


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PostPosted: Wed May 15, 2019 9:03 am 
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Brazilian Rosewood
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Looking good!
If you radius your tops one thing to be careful of is making the vertical edge of the bridge too thin. Most of the old parlor guitars had "flat" tops so sanding a radius into the underside of the bridge was not needed.


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PostPosted: Wed May 15, 2019 10:37 am 
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Brazilian Rosewood
Brazilian Rosewood

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Most of the sanding will happen in the center of the bridge anyway for the radius. I normally just glue them flat anyway, even on a radius. Unless the top has a pronounced radius which some of my designs do and in that case I will arch the bottom of the bridge. One thing I would do next time though is start of making the bridge just a bit wider then necessary that way mistakes could be corrected by sanding or planing the bridge back to it's intended width.


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