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Building vintage gibson ish guitars. I read some really gibsons have 15/16 x6 inch bridges. I have a lovely piece of tucurensis here 18 inches long but only 7/8 wide. Too thin? With a drop in instead of through saddle? get over it and cut up something else?

Does anyone know of a Gibson-specific forum where this question might get more of an audience?

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Peter Havriluk

Here is what ChatGPT has to say

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I think it's halucinating.

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That’s funny. When I read stuff like that, I don’t worry about losing my job so much.

I think it’s playing dumb to lure us into a false sense of security . . .

No it used to work for Ov*tion though....

Gibson was a toy factory who when they did not have enough orders for toys made guitars. Often people try to assign some genius to what Gibson did or how they did it but much of the time what we see that they produced including dimensionally is because it's what they had.

They built with what they had and this is actually taught in Lutherie schools. Just like you Mike you have a chunk that you want to use and so did Gibson back in the day, Leo Fender too.

Dimensions used were often problematic including a tendency for the saddle to split out the front of the bridge because there was not enough wood/meat left in the design.

Something to keep in mind when thinking about Gibson.

"Do not go to AI for counsel, for it will say both no and yes"

Lute bridges are basically just the tie block from a Classical guitar, with some small ornament on the end. They're often not much more than 1/2" wide, and 4-5 inches long, and can carry the same string load as a guitar. They do require re-gluing from time to time, particularly when they've been 'toothed'.

One critical dimension that doesn't often get mentioned is the string height off the top. The glue line is carrying two sorts of loads: a shear load equal to the tension on the strings, and a torque load that is product of the string tension and their height off the top. Both loads are highest at the front and back edges of the bridge, with the torque load pushing the front edge down and pulling the back edge up. When the sum of the two along the back edge of the bridge exceeds the peel strength of the glue the bridge pulls up. Note that when the bridge tilts toward the neck some of the shear load is changed into an upward pull, which doesn't help in keeping the bridge down.

There's not much you can do to reduce the total shear load. Making the bridge wider along the line of pull (from front to back) spreads it out over a wider area, and disproportionally reduces the shear at the edges, which is why 'belly' bridges stay down better than 'bar' bridges, even though a standard Martin bridge can have a smaller footprint than a standard Classical bridge.

Reducing the string height off the top reduces the torque in proportion. They use this on Flamenco guitars to allow for making the top lighter, increasing the 'attack' and power at the expense of sustain, and changing the treble/bass balance. If you can lower the string height a bit that will make the glue joint more durable.

It does tend to reduce the break angle of the strings over the saddle, of course, and you may have to do something like ramping the string slots to get that back. Most people worry 'way too much about break angle, though. So long as the string isn't rolling or sliding across the saddle top as you play, and it's not hopping off as it vibrates (and you'd hear that!), you have 'enough' break angle to transfer all the string energy to the top. Something on the order of 15-18 degrees should be 'enough'.

So, if the neck set will allow it I'd say go ahead and use that bridge blank, but keep the strings down closer to the top: 3/8" rather than 1/2", say. Also, do a really nice job of fitting and gluing it...

The Jimmie Rodgers Weymann replicas I built in 1990-91 had pyramid bridges that were around 0.900" wide. Those also had long through saddles.
No problem so far.....
When Monteleone saw one of those, he stated that the bridge was too small and would never stay attached for long.
That was 33 years ago.

Sent from my SM-G950U1 using Tapatalk

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John

like John Arnold posted above
I do L2 and L00 copies and they have 7/8 wide bridges
I have glued with tite bond and Hide glue , none came off yet.

I don't know if I would go any smaller though

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Brilliant. Two John's say yes. I'll carry on...

Thanks so much everyone, really appreciate it.