Prototype Bridge

[glasalle1]

I am working on a prototype bridge for my Jumbo Prairie State Model guitar (17.25 in lower bout). I based this off the bridge that Jon Lunberg made for Stefan Grossman's 30's Prairie State guitar in the 60's. The bridge will ultimately be ebony but I am using a piece of Madagascar Rosewood for the prototype.

First up, cut the saddle slot. I actually had alot of issues after this was done slotting another test bridge, where the bit broke in half!

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Cut out with Bandsaw. After carefully marking all the measurements to ensure everything is symmetrical, I used my Auriou Round 3/8" rasp:

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These are roughed out, for the prototype. For the final I will make sure everything is consistent.

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Glenn

[glasalle1]

I then Used my Dragon Rasp to ramp down the point on the bridge. I had some chip out on the corners, so will have to be really careful with the ebony. I also sanded a bevel on the back of the bridge.

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Here is the ebony piece I will be using for the 2nd prototype. I also have to drill the bridge pin holes. The Mad Rw bridge so far is 29 grams, so not too heavy. I have more sanding shaping, and of course need to drill the holes.

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Glenn

[tippie53]

very interesting

That's pretty cool. I've never seen a bridge like that.

[glasalle1]

Hopefully tomorrow I can get some more done. I worked a bit on the ebony bridge today.

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Glenn

[Dave Sayers]

I noticed your comment about chip out with the dragon file. I have found these extra fine Japanese files excellent. They can be used with only the most minimal pressure to do the finest of smoothing. They come in fine and extra fine and are not cheap but they are actually better than the red handled ones. I hope this link works.
http://www.ebay.co.uk/itm/Japanese-Carv ... 4843aff93b
I am not suggesting you buy from UK ebay, but I'm sure someone in America must be selling these.

[glasalle1]

I noticed your comment about chip out with the dragon file. I have found these extra fine Japanese files excellent. They can be used with only the most minimal pressure to do the finest of smoothing. They come in fine and extra fine and are not cheap but they are actually better than the red handled ones. I hope this link works.
http://www.ebay.co.uk/itm/Japanese-Carv ... 4843aff93b
I am not suggesting you buy from UK ebay, but I'm sure someone in America must be selling these.

The link isn't working - What is the brand?

Glenn

[glasalle1]

Well, During the vid shoot at John's, We worked a bit on my bridge. And John used the Milling machine to cut the slot as well. Nice tool :-). I like it, and will be using this one for the guitar. I made a clear template of the bridge, and need to update it with the location of the bridge pins. John cut those on the milling machine as well, and i really like the placement.

Here is the Bridge - Still need to sand in the ramp on the back:

IMG_2546.jpg

And here it is sitting on the guitar. The more I look at the ebony FB and Bridge, the more I see I need to darken that rosette (spalted Maple). I think some z-poxy on it when i finish will give it the golden color.

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Glenn

[Darryl Young]

Glen, that is just beautiful! I really like it and I like something different and you have it here.

Thanks, for posting......and yes, I want a milling machine......<smile>

[Dave Sayers]

Sorry Glenn, the link seem to work from my computer. Here's a picture of the japanese carving file, or japanese file, which I lifted off of ebay. I also have the red plastic handled japanese carving files and the japanese rasp saw but these files seems to be a lot less aggressive and smoother to use, especially on thin wood. A noteable characteristic is the red laquer just visible above the wooden handle and the two lengths, 150mm (15cm) and 200mm (20cm). They are usually available in fine and extra fine, although I do have one which is coarse / fine.