Need bridge thickness for 76 Gibson J-45/50

[Paul Breen]

I have acquired a 76 Gibson J-45/50 that I suspect has had the bridge thinned to get the action lower on a guitar that needs a neck re-set. I am hoping someone has access to one and can provide an unmolested bridge thickness.

[Paul Breen]

I sent an inquiry to Gibson and received their response this morning.

"Unfortunately, we have no ’76 models available to take bridge measurements from and we have no archived data available for the dimensions of bridges used back in 1976"

Well, no help there...

Hoping someone has one of these instruments and can measure their bridge thickness for me, thanks.

[Bryan Bear]

I think at this point the more important questions are what to do going forward. You need to determine if you are going to make a new bridge or not when you re-set the neck. You should be shooting for string height above the soundboard (at the bridge) of about a half an inch.

What is the string height now? How much will you need to raise the string height to get to that half inch range when you reset the neck. How thick is the bridge now? How much saddle is sticking out. Will a taller saddle be appropriate or will you need a thicker bridge?

In my non-professional opinion, the thickness of the original bridge isn't really all that important as long as you get the geometry right. That may or may not require a new bridge. I'm not sure how Gibson did things in '76 but some factories had different bridges to choose from when assembling each guitar to get the geometry right. I don't think anyone will care if the thickness is original as long as it plays properly.

[Paul Breen]

Thanks for the comments Bryan.

This is one of my own projects, not client repair work and I am in no particular hurry to get it done.

You are correct that the geometry, getting it back to where it should be, will drive my decision making. It absolutely will need the neck re-set and I'm sure the reason some previous owner thought it a good idea to thin the existing bridge. Any changes to bridge thickness need to be done before the neck is reset. Since I have the luxury of time, I thought it worth my while to try and find out what the original bridge thickness would have been on a 76 J-45/50 model. If I get no definitive answer, I'll proceed seat-of-the-pants.

Martin uses 3 bridge thicknesses; 5/16", 11/32" and 3/8". I am pretty sure Gibson bridges range from 1/4" to 5/16" on acoustic models with drop in saddles. Your right that nobody will care about bridge thickness if the geometry is good. I always like to do some research first on my projects and make an effort to put things back to stock defaults when possible.

[Carl Dickinson]

I've got a '72 Gibson Gospel that I bought in '73. Just measured the bridge thickness at 19/64+" off the finished top. I think I recall regluing the bridge in '76 and needing to scrape some finish off under it so it's probably 5/16" originally.

[Paul Breen]

Hi Carl, thanks for responding.

I have gotten a clueless response from Gibson and have this question posed on 3 different forums. No one has come forward so far that can measure an actual Gibson J-45/50 bridge. The J-45/50 was a transitional model that absorbed the J-50, came out in 76. Gibson has done many variations over the years how they construct their instruments, some not so good and dimensions not necessarily cared over to the next generation of the model. At this point, I'll likely go with the 5/16" thickness but I'll bide my time and see if anyone comes out of the woodwork with an actual J-45/50 bridge dimension.

[Michael Lewis]

Most Gibson bridges I have seen are 1/4" thick. Martin are 5/16" now, used to b e 3/8".