73 guild f112 project / suggestions appreciated

[peetar]

Took a long drive to check out the guitar that was in great shape and when the kid opened the case I was stunned. Action was 1/2 an inch, Bridge was lifted, top pregnant, can slip a card 1/2 was up the side to the dove tail. neck relief was .024. No cracks and it had the inlayed guild and logo instead of the silk screen "guild". I told him it was toast but gave him $100 because I want a cool 12 and a big project.

I have not found any loose or cracked bracing on a fast look / feel. Going to do a deep inspection tonight or tomorrow.

1. Bridge: I was thrilled when I got home that bridge looked to be Brazilian. Took it off and measured and it was .301 at the low E and .257 at the high E (at the front) with a pretty good slope going from back to front of the bridge. I assume it has been shaved (I think a real player owned this back in the day, fretboard wear up to the 14th ). My initial plan is to make a new bridge and install a bridge doctor. The idea of setting the neck to a shaved bridge seems wrong to me and a lot of material would have to come off the back (underside) to create the appropriate saddle angle and fit the bridge to the slope of the bellied top. It might be that I could reuse the existing saddle because the bridge doctor would offset tension but I just don't know.

The high point of the belly is at the very back of the saddle. Between a quarter and a quarter and a dime across the widest points of the lower bout. Length wise there's under .010 of sunken top from the neck joint to the front of the bridge. Then ski slopes up.

I would greatly appreciate any thoughts or advise on this. If we're going with a new bridge I'd like to order/ rough it out ect.

Thanks guys, I'd really appreciate input.

[phavriluk]

Bridge Doctor? I suggest doing all the repairs and adjustments before installing one. My opinion is that if Guild didn't install one, it's not needed at best and detrimental at worst.

[JonWint]

Belly height is "quarter and a dime"? Is that thickness? My quarter and dime measure 0.12". A belly of 0.25" is acceptable.

What is bridge rotation angle? Up to 2 degrees is acceptable.

Why not do a belly reduction (if needed) with the TJ Thompson system or equivalent?

Does neck have adjustable reinforcement?

Why not add thickness to the bridge by laminating similar wood to the bottom and reshaping as required?

Post some photos.

[phavriluk]

JonWint's comments provoked a thought - - - did Guild dome their soundboards? Nice to know whether the 'belly' OP noticed was a construction feature. Guilds have had a reputation for being the bar-fight guitar of choice, so I wouldn't be losing sleep over a Guild's basic structure. Nice to know if some ignorant owner shaved any braces to 'improve' the instrument.

Quarter one side of the lower bout, dime on the other?

And laminating on the bottom of the bridge sounds like a good idea to me. Saves the OEM bridge.

I sure like the idea of restoration and resuscitation of needy instruments. There's character in there!

[peetar]

Thank you for the comments.

I really need to learn to post photo's.

I like the idea of laminating thickness to the original bridge.

This guy has two functioning truss rods.

When I mentioned the "belly" lower bout to lower bout, I'm fine with that radius. Just mentioned it for info. It's the forward tilt at the bridge location that has me worried. It's dramatic and just at the footprint of the bridge. When I got it it had 6 strings under tension with the back of the bridge up in the air. the front of the bridge had slid forward about 1/16+ in. Guessing extreme humidity / temp cycles with all that leverage at the front created the slope. The bridge plate looks fine.

I don't want to put on the Dr., and if I do it's not in hopes of changing the shape of the top, but to give it some support. I can offset that angle fitting the bridge. But if I don't plan on installing it and then I have to when I'm setting it up, then it actually moves the top a bit, it would screw up the saddle slot angle ect.

What do you think about installing the bridge with the Dr., do the rest of the project. When it's set up and playing, back the tension off the Dr, and if everything is stable I can take it out, fill the hole with dust and CA ?

[phavriluk]

(1) I'm unqualified to opine about Bridge Doctors. Never even met one. I suggest doing some research on these things before committing to installing one first. I'd be doing that last, once I was sure that the guitar structure needed one. (2) Guilds have reputations of being right sturdy, and the idea of installing one on a Guild seems strange to me. But see above. I'd be doing a thorough review of the guitar's structure first. Loose or broken braces cause awful distortions.

Good luck with this project.

[schoolie]

Take it to a good luthier. It probably needs a neck reset and might have loose braces. It will be worth the money since you only have $100 in it.

[JonWint]

What is bridge rotation angle? Up to 2 degrees is acceptable.

If bridge rotation angle is acceptable, a neck reset may be all that is required.

A Bridge Doctor is effective at reducing top vibrations. Its use is often a result of failure of correct problem diagnosis or unwillingness to perform proper repair methods.

Post photos.

[peetar]

I purchased as a project (doing all the work myself). It does need a reset. That's the reason I'm hung up on the BD. If the elevation of the the bridge changes under tension, I'll end up over /under setting the neck angle. My theory is :

1. Set a bridge of proper demensions. 2. make a refernce block I can lay over the sound hole (1/2in.? minus the difference the strings sit off the extended fretboard plane over the sound hole).

Then when I'm creating the new neck angle I can use a straight edge down the fretboard to the top of the bridge. I'll have that sound hole refernce so I'll know if it's too high and have to figure something out.

Starting this whole thing beginning of next week. There's a stamp under the top Aug 28 1973. I fully intend to have it playing (with good intonation) on it's 50th birthday.

[peetar]

Originally Posted by JonWint

What is bridge rotation angle? Up to 2 degrees is acceptable.

If bridge rotation angle is acceptable, a neck reset may be all that is required.

A Bridge Doctor is effective at reducing top vibrations. Its use is often a result of failure of correct problem diagnosis or unwillingness to perform proper repair methods.

Post photos.

I'm sorry about the photo's. I'm pretty sure (will check tomorrow) that the rotation exceeds 2 degrees and nearly doubles that.

The one thing I have not done is remove the cloth at the X brace.

Are you saying that the original bridge is an acceptable thickness? I'd love that, but don't see it . I'm going to take off the neck and cut , fit and glue an oversized shim for the bridge Monday evening unless I get talked out of it (the bridge part).

I am asking for advice .I appreciate all responses. Please realize it was multitudes harder to remove the plastic bridge pins than it was to remove the bridge. The bridge "slid" up the top (shaved side) over an 1/8th of an in.

It's an old, warped, bottom level Guild that was going to stay dead if I didn't give it a try. It would sell 4 $1K fixed up I am going to make it my 12 string. I get why purists say what they say, but I have 13 screws and a plate in my ankle and without it I'd be a gimp.

[Fathand]

Originally Posted by peetar

.

Are you saying that the original bridge is an acceptable thickness? I'd love that, but don't see it . I'm going to take off the neck and cut , fit and glue an oversized shim for the bridge Monday evening unless I get talked out of it (the bridge part).

I am asking for advice .I appreciate all responses. .

Gibson makes bridges down to 1/4" thick, possibly thinner on the treble side. I would think yours is passable.

[redir]

What does this mean?

"can slip a card 1/2 was up the side to the dove tail. "

[phavriluk]

I think it means the neck is loose in the dovetail opening. That sure would make resetting the neck easy - - - which needs to happen, from my inference from the comment.

[redir]

Originally Posted by phavriluk

I think it means the neck is loose in the dovetail opening. That sure would make resetting the neck easy - - - which needs to happen, from my inference from the comment.

Good head start on a difficult neck reset.

[peetar]

I made a nice little steamer on Monday so I ended up taking the neck off Tuesday.

My mistake was I removed the fret and drilled the hole to the "pocket" before separating the fretboard extension from the top. When did that, the neck came off in 10 seconds without any steam.