Official Luthiers Forum!

After checking the intonation at the 12th fret it is consistently 10+ cents sharp on all strings...unbelievable!

I doubt that it would be possible to widen the slot to make this correction...the back of the saddle would then be too close to the string holes. The only correction would be to replace the bridge. But then the holes wouldn't line up...so they have to be filled, bridgeplate replaced and new holes re-drilled. How could such an error go unnoticed by the company!

Mario...or others who have dealt with the issue...how has Martin dealt with this? Is it covered by their lifetime warranty?

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JJ
Napa, CA
http://www.DonohueGuitars.com

Don't let them "fix" it under warranty!!! They'll add an oversized bridge! arghhhh! ugghhhh....

The fix is to move the saddle back as far as it -can- go. It will get close. Note that you never noticed before, so it's not -that- critical, is it? Now, if you're ear is fussy, move it as far back as possible, angle it back 8 or 120 degrees, and in the new bridge(oh yeah, new bridge..), angle the pin holes, also. This will leave you a decent and not excessive break angle, and move the saddle to just about perfect. If you still need some further compensation, and you truly can hear it(be honest with yourself, now), then you can move the nut up closer to the first fret, either with a ledge, or by shaving 1/64th or so from the end of the fretboard.

The best time to gain some intonation was at the neck set time, where shims could have bee made(and made invisible) to move the neck up(away from the saddle). This, in combination to the bridge work, brings them in perfectly. And again, 100% reversible. No oversized bridge(and resulting oversized bare spot on the top), no new bridge plate and holes in the top.

Intonation can really kill volume, believe or not, because it completely screws the overtones, of which make up a large percentage of sound.

Spoon feed time...

here's my fix for a tubby, quiet 70's D-28/D-35. In order of work, as budget allows.

a) Fix intonation(work with existing bridge if owner can't afford next step)
b) replace bridge with intonated(read above re: saddle and pin holes) BRW or MadRW bridge with long saddle
c) bone pins, unslotted, slotted bridge, tight fitting strings
d) replace gigantic RW plate with small maple
e) bone nut if the original isn't ivory. If ivory, leave be if possible(depends on setup).
f) replace tuners with Waverly, including plugging old holes and re-cutting them properly(stepped holes).
g) shave finger braces(only!)
h) Tune up and enjoy. Find banjo player; proceed to submit banjo player to attitude adjustment.

I'm not surprised that I never noticed it...5 years ago I didn't even know how to spell "intonation"! But it sure was apparent once I pulled it out of its case tonight and played it up the neck. So I guess I must change it now!

Thanks for the learning experience, Mario. It really all fell into place once the Saddlematic told the tale, so the spoon feeding was minimal. Still hard to believe that Martin could have allowed this to happen.

Thanks again!

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JJ
Napa, CA
http://www.DonohueGuitars.com

Their jigs wore out, and the bridges moved more and more forward. They caught it around late 74 or early '75, and fixed it.

Same jig wear is responsible for the ever larger radius on the headstock corners. Many of us can accurately date a Martin by how round the headstock corners are <g>

.....but then again, some of us have an unhealthy preponderance toward silly details.

By the way, don't go simply with the saddlematic! Test the intonation, and do some math if need be.

The entire scale may be a little "off" from what the saddlematic expects, so go with the real world. I'd be surprised if a '70 needs more than 3/32". And when checking intonation, toss the 2nd and 6th strings out of the equation. They'll never be perfect. Keep that in mind! Get the others in tune, and these two trouble makers will do what they do, so don't argue with them....