!949 Martin D-18 ; foctory bridge placement

[Dale A. Bender]

Hey everybody

Received a 1949 D- 18 Martin in my shop for evaluation. Seems the bridge may be incorrectly placed from the factory. Problems:

1. bridge has been thinned , and , saddle height has previously been lowered , to improve high action , when a neck reset would have been the ideal solution.

2. 12th fret intonation check indicates the correct position for the saddle @ treb. E string  to be about 1/8 in. toward soundhole from current position. This is not even over  the bridge.

3. same situation for saddle @ 6th string...saddle should be about 3/32 in.  toward the sound hole from the original position.

4. Martin indicates a scale length of 25.4 in is appropriate for pre 1960s.

5. My measurements ( using a stewmac saddlematic ) keying off the 12th fret ( nut to 12th and using same measurement from 12th toward bridge ) place the saddlematic treble wire marker at 1/32 in. shy of the bridge ; and, 8/32 in. shy  from the crown of the saddle where the 1st string crosses.

       Have any of you run into this on the D-18s before? Or is this particular D-18 just a friday made guitar .

       My 13 years of repair instinct tells me that the bridge is in the wrong place . That I should make a new oversize width bridge ,and , cut the saddle slot in the correct new position. Oversize to cover up the bridge footprint outline on the top.  BUT THIS IS A 1949 VINTAGE MARTIN we are talking about here. Although I have much experiance in all phases of guitar repair, and feel that the intonation would be much improved , and a neck reset would greatly enhance the playability of this instrument,  I am more than a little apprehensive about ruining the value of this instrument by making necessary design improvements on the bridge.

Any thoughts ?

[Mark A. Kane]

The amount the bridge is out of place seems incredible. The intonation must be off by a half step, maybe more? Does it SOUND as bad as it sounds? I use the Saddlematic and find it quite accurate. Is it possible the nut placement has been modified (fingerboard shortened)? can you post pics of the Saddlematic in both positions, just to satisfy my curiosity? If the bridge is out of place that much, I'm not sure an oversize bridge is the answer. Paul Hostetter, are you out there? I'd like to hear your take (and others,too!). Pics please!

[Dale A. Bender]

The guitar does sound off. Incredibly though, it doesn't sound  ' that bad '. Although, my ears have been deadened over the years by the  high pitched whine of shop tools. I think a player with perfict pitch would find it maddening to play. Nut seems t be in original position, with no nut slot alterations to string length. Post pic's ? My friend, I'm almost into the 80s when it comes to high tech  manipulations on the www. Sorry. Gotta work on that.

[Ned Knepp]

Before I jumped off that bridge, I think I would talk to the owner to see if they have noticed the problem. It sounds to me like it would be way off too but it wouldn't be the first time I came across someone that plays but can't actually tell if their guitar is in tune. It's their investment and their decision about making a possible modification. It may be a non-issue to them.  Did they mention Intonation when they brought it in or just the string height?

[Dale A. Bender]

The owner has passed and the guitar was brought to me by his son, the new owner, for evaluation / repair.

[Mark Pollock]

I'm SURE you have checked it, but then, intelligent people are perfectly capable of being fooled, just much less often than the rest of us, sooo...

 

Is the nut correct? String height good? Is the position of the nut relative to the first fret good, and do the slots end in the right place?

 

Is the fretboard original? Has it been replaced? Has this guitar has some kind of "slip the block" reset done in the past that screwed everything up?

 

Something sure smells here...

 

Mark

[Dale A. Bender]

Those questions all were also on my mind. All the positions of nut, slots , and , fretboard seem to be in original positions. There doesn't seem to be anything surrounding the heel/body junction ( smaller heel profile in relation to the footprint of heel on body , tool marks on body near heel or heel,etc. ) to make me think it has had a previous neck reset.

[Frank Ford]

Postwar 1940s Martins frequently have the bridge out of position - to the rear and playing flat.  And, it presents a nasty problem to correct the intonation.  Most of the time, we crowd the saddle as far forward as we can to avoid using a wider bridge or trying to move a standard-width one.   Most of us can tolerate flat notes much better than we can sharp ones.

 

By the way, 1/8" movement of the saddle changes intonation by a bit less than ten cents:

 

http://www.frets.com/FRETSPages/Luthier/Data/compcalc.html

[Dale A. Bender]

Thanks for the info Frank. I've been told by a guy in the warranty repair department at Martin that their more contemporary  guitars have a  +/- 4 cents  tolerance for specs.

[Tim Mace]

Why no pictures yet?I enjoy lookin' at old Martins.......let's see it!

[Mark A. Kane]

I've used this formula with great success over many years (found it on Frets.net of course), and find it to be a highly useful and trouble-free way of dialing in a compensated bone saddle. I can get the individual strings within a cent or so without a lot of trouble. Without this calculation, I struggled to get it right at the expense of a few (read many) tossed saddles. Thanks Frank!!!

[Jim Bancroft]

Yes, some late 40's Martin's are slightly flat, from the day they were built. I have a 1949 00-18 that the saddle is probably back 1/8" more than it should be.

You can correct the problem when you reset the neck. Just shorten the heel slightly during the reset, doing so you move the fretboard closer to the bridge, shortening the scale, thus correcting the flat intonation. Being the bridge has been thinned it may need replacing, but it can be replaced with an exact replica and not modified in any way.

That is what I would do.

Also as Frank said, flat intonation is easier to tolerate than if it's too sharp. Using a capo, and just the fact that strings are stretched during fretting, is a good reason to have intonation slightly flat at the 12th fret.

On a guitar with correct intonation, I have found that the measurement from the nut to the center of the 12th fret, when moved from the center of the 12th fret to the saddle, that distance will end up at the front edge of the saddle(or 1/32" before saddle), this on the first or high E string. The low E will be set back farther yet of course.

 

Jim

 

 

 

[Dale A. Bender]

Thanks Jim,  

 I appreciate your feedback . I have been gravitating toward the string length / neck reset fix myself.  It should be an easy to do , and , aesthetically   un-noticeable , and , value holding repair solution. I will have to make a new bridge , but , I will duplicate the the original design to replace the over-thinned one , which is on the top now.

 

Dale