Advice for changing bridge type mid-build

[Marc Boyd]

Hi folks. My first post for a long while but have been lurking here pretty consistently!
I'm about 95% complete on a Gibson Advanced Jumbo style guitar for a friend of mine (25.5" scale).
It was originally designed for a vintage style 1" wide straight bridge, so my bridge plate was designed to accommodate this at just over 1" wide (bridge is not yet attached but body is fully complete). For primarily aesthetic reasons my friend was wondering of we could replace it with a Martin style belly bridge. This would leave about about 3/8" (10cm) of the back end of the bridge unsupported by any bridge plate material, which is no way that I would ever purposely design a bridge plate. The front of the bridge would be unaffected since it would still be in line with the plate.
I am not particularly keen to replace the bridge plate with one that will accommodate a belly bridge at this point in the build (scratch that, I will not be doing it)! My instincts tell me to proceed with the original bridge, but it did make me think... am I truly in danger of building a structural time bomb if I proceed to install a belly bridge over a slightly larger then 1" bridge plate? If anybody has had a similar experience or would like to share some wisdom/speculation then I would be happy to hear it.
Thanks!

[Clay Schaeffer]

As long as the bridge pins go through the bridge plate you will probably be O.K. If you need to you could move the pin holes a little closer to the saddle to keep them in the bridge plate, but most likely that won't be necessary.
Not having a full width plate won't offer as much structural support as a wider plate would, but the wider bridge with the narrower plate will offer more support than the narrower bridge with the narrower plate you were originally planning on.

[Barry Daniels]

I have made changes mid-stream for customers in the past that required design compromises, but I don't plan on ever letting that happen again.

[Steven Smith]

I'm with Barry, I would tell them it's not a reasonable change at this time.

[Clay Schaeffer]

Personally, I wouldn't have any heartache about changing the bridge (as long as the pins still fall in the plate). There was a reason they went with a wider bridge, and it wasn't aesthetics. The larger footprint helps the bridge stay put. But it is your project and your friend. If you wanted to "extend" the plate, you could put a Musser brace behind it.

https://umgf.com/mario-proulx-guitars-t178106-s20.html

[Marc Boyd]

Thanks for the replies!
The saddle/bridge pin configurations of my belly bridges and straight ones are located the same distance from the front of the bridge, so they both hit the bridge plate at the same location. I'm still leaning towards the original bridge, but it's really given me the opportunity to reconsider the relationship between the bridge and the plate.
Really enjoyed reading about the Musser brace, Clay. Even if I don't use it as a potential solution for this issue, I'm glad that I'm aware of it now as something new to add to the toolkit!

[Barry Daniels]

I think the bridge plate should extend in front and behind the bridge in order to minimize bridge rotation. Of the two, the extension behind the bridge is probably the most important in terms of strength because the X-braces are further apart leaving a relatively weak area. If the plate is short of the bridge, you can get a hinge effect on the top at the edge of the bridge.

[Michael Lewis]

Mario Proulx put a brace very similar to the Musser brace. It helps keep the top flatter behind the bridge when tension is applied to the strings. I forgot he used acronym but it was for ". . . magic tone producer" or something similar. It works.

Also, just adding to the rear of the bridge plate would help support the stresses involved. So you see, there are some ways around the problem.

[Clay Schaeffer]

PMTE - Proulx Magic Tone Enhancer.
Has anyone heard anything from Mario lately?

[Matthew Lau]

Dunno. Glad he's in Canada. Should be safer than here in the states.