How to make a Pyramid Bridge

Got a new way of doing something? Or maybe an old method that needs some clarification.

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Allen
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How to make a Pyramid Bridge

Post by Allen » Sun Jun 01, 2008 5:20 pm

Bob Connor recently sent me a beautiful Brazilian Rosewood pyramid bridge to use on my current project that's a size 5 terz guitar. I wanted to be able to replicate this bridge with local hardwoods so set about figuring out how to do it without a CNC mill, so here's my take on how to go about it.

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Here is the original that I'm doing my best to replicate, and my bridge blank material.

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To replicate the very tight radius on the wing I'm using a Forstner bit.

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I also moved the blank along and used the Forstner bit to remove the bulk of the wood on the wing.

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I use a tilting sled next to my belt sander to thickness the wing. This shot shows the first bridge I tried and you will notice that the radius cut by the belt sander is no where near right. That's why I went to the Forstner bit.

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I used double sided carpet tape to stick the pyramid stock to a piece of hardwood that I dimensioned to the desired size of the pyramid.

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Then set the miter gauge to 60 degrees and gradually sand away the sides until the bevel just meets the edge of the hardwood stick. Go easy and don't try to get each side done in one go. I found that it worked best to just kiss the bevel of the pyramid to the sandpaper, then rotate. Keep doing this until you're at the finished dimension.

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The finished pyramid removed from the double sided tape. All that's left to do is warm up the hide glue and stick them down. As it's not a stressed joint I just made up a thick batch of glue and held the pyramids in place for about a minute. No clamping involved.

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My finished attempt, the glue isn't even dry yet. :D
Allen R. McFarlen
https://www.brguitars.com
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Cairns, Australia

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Dave White
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Post by Dave White » Sun Jun 01, 2008 6:52 pm

Allen,

Nice one. Frank Ford shows how he carves one here on his brilliant frets,com website.
Dave White
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Kim
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Post by Kim » Sun Jun 01, 2008 7:17 pm

Nice work Allen, very clever. Is that a bit of Tassi Blackwood??

Cheers

Kim

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Allen
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Post by Allen » Sun Jun 01, 2008 8:56 pm

Yes, I read through Frank's tutorial and had thought about doing it like that, but to get the really crisp lines on the pyramid I though might be a bit tricky. Besides these Australian hardwoods are just so bloody hard that a chisel hardly want to scratch them.

The wood is some Gidgee I think. I got it in a large selection from Tim a while ago. Sounds like metal when you drop it on the concrete floor. It sands well, but other tools don't have much effect on it.

The Brazilian Rosewood bridge weights in at 19.7 grams and the one I made comes in at 30.2 grams. I might have to do a little shaping to get some of the "fat" off.
Allen R. McFarlen
https://www.brguitars.com
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Cairns, Australia

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