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Posted

i was surprised after doing a search that there weren't a couple of threads about the bridge doctor. i took a martin flat top in for some work yesterday and found that the top below the bridge is starting to bubble up some. no broken or loose braces.

(i originally posted this in the wrong section so i'm trying here)

the string height is 4-4 1/2 mm at the 17th fret with the neck set almost straight and the nut slots down pretty low. after googlin' bridge doctor i came up with a couple of questions.

i can see how the device would pull the top down and keep it from getting worse but would it actually help with string height? i can't quite get my mind around it. it appears to me that since it's pivoting the bridge and it's mounted behind the saddle that it might actually raise them. anyone had any experience with them and if so what does it actually do to the string height?

also can you think of any reason not to make your own? i stopped at the hardware store this morning and bought a threaded wood insert for 95 cents and a bolt to fit it for much less than that. add a block of scrap wood, a dowell rod and a couple of screws to mount it and it seems like you'd be in business. stewmac wants twenty bucks for them...i like my price better.

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"When life gives you lemons, build a Strat"

Posted (edited)

First of all, is the guitar in a properly humidified environment? High action is a typical symptom of an overly dry acoustic guitar.

Edited by Saber
Posted
First of all, is the guitar in a properly humidified environment? High action is a typical symptom of an overly dry acoustic guitar.

saber there's no telling..the customer is a buddy of mine and he keeps it in the house out of the case on a stand so whatever the humidity is on any given day that's what it's exposed to..changing environment i guess you could say.

Posted

Instead of treating the symptom, it would be a better idea to stabilize the guitar by putting it in a case with a hygrometer to monitor the humidity. Then either use a guitar humidifier to raise the moisture if it's below 45% or a dessicant if it's above 55%. After maintaining it between 45% and 55% for a week or two, it might come back to normal on its own.

Posted

that's probably very good advice sabre and i may suggest it to the owner. but i'd still like to leave the original question open.

has anyone used the bridge doctor and if so what effect did it have on string height?

thanks again.

Posted

fitted around 20 bridge doctors to rectify sound board bellying

all had lower action at the end. all were louder. 75% at least of all the clients believed the "tone" was better. Sustain also seemed to be improved.

Posted
fitted around 20 bridge doctors to rectify sound board bellying

all had lower action at the end. all were louder. 75% at least of all the clients believed the "tone" was better. Sustain also seemed to be improved.

I've only installed one but I found the same thing, it was like a new guitar.

To some extent all acoustics will show a little belly bulge in time unless it's braced so heavy that the top wood can't move. Proper storage and light strings may help slow it but that pot belly happens to the best of us.

I don't see any reason why you couldn't build your own, it's a beautifully simple device. Give it a try and let us know how it turns out.

Posted

thank you gentlemen..that's what i wanted to hear. and i'm going to build it tomorrow and i will let you know how it works.

i was aware of the increase in sound..in fact during my research it seems that some guitars are coming from the factory with them installed already. and you're right..they are simple..so simple i wonder why one of us didn't think of it first. :D

Posted

I did not use the bridge doctor that they sell but made sort of the same thing to flatten the back-of-bridge belly on a POC Fender out of wood (no screw). The only problem I had was I had to make a new saddle insert that was about 1/8" taller because the action was too low after the top was flat. The strings didn't all hit the insert very hard. Buzzed a bit and the action was too low. You might find the guitar action kind of unstable for about a week. I did. Flattops rock! :D

Posted

gripper, i'd be happy to have to make him a new saddle if it pulls the action down that low. that would just mean that it works really good. but truthfully the action isn't that far out now..i'm just trying to pull it down a bit and to stop the bubblin'.

Posted

Breedlove installs Bridge Doctors in their new guitars from the git go, having designed them so lightly that they can't hold up to the tensions without them. I know Dave Berkowitz used one as a design component in his first Baritone, don't know if he's installing them in all of them, though.

All good acoustics should belly somewhat behind the bridge, though. It's a sign it's been built more or less correctly, not too heavy. Larrivee builds 'em flat behind the bridge, f'r instance, and lets the strings pull the dome into them. Many others (most, these days) build them slightly arched anyway, but the strings still pull a belly into it. It's when it gets excessive, and particularly if the soundboard starts 'dipping' in front of the bridge that the only solutions (in my mind) are a) a bridge doctor or :D a new top. Personally, if the belly increases a touch, but the top's integrity is good (no dipping in front of the bridge), I'd think a neck reset is the 'correct' repair. But a Bridge Doctor is much, much cheaper.

Posted

well, i said that i would follow up on the results of my homemade bridge doctor so here it is. i have to say that the whole thing was a success and extremely easy to make and install. i used this design.

http://www.ukuleles.com/BuildingHowTo/ukuleleBD.html

making it was simple. i cut a block of red cedar 1 1/4" x 1 3/4" x 3 1/2 ". on one end i cut a slot 3/8" x 5/8" on my band saw to make room for the bridge pins after installation. on the other end i drilled a hole completely through the block for the brass insert and the dowell rod and that was it. on the bridge itself i drilled a 1/4" hole, the size of a fret dot, the proper depth to receive a fret dot and the small diameter screw that i used to attach the bridge doctor. in other words after i mounted the device i covered the hole with a black fret marker.

mounting it was fairly simple also. i inserted the screw til just the tip was protruding into the guitar and placed the device inside the guitar and pressed up on the screw to mark a place for the pilot hole. after drilling the pilot hole i mounted it temporarily. i then placed the dowell rod inside the guitar placing one end against the end block of the guitar and the other end against the side of the cedar block. i marked the length to the neck side of the block with my thumb nail and removed it. i then removed the bridge doctor and marked the dowell to the right length..in other words deducting the length of the brass insert plus probably 1/4" extra so that i'd have room to re-install the whole assembly. then i inserted the screw into the insert, the dowell into the hole and re-mounted the bridge doctor. with a short phillips head screwdriver i screwed the scew in until i got the flatness that i wanted on the top. bingo..done.

total cost? 95 cents for the insert, 50 cents for the screw. i had the cedar and the dowell rod so basically i had $1.45 invested. it probably took no more than ten minutes to make it and another 20 to install it.

the only negative thing about it is that it didn't drop the string height very much but i honestly didn't think that it would. my logic was telling me that since you're using the bridge as the pivot point for the whole assembly it might actually raise the strings a bit. but it definitely took the belly out and i made three more to keep here in stock for future repairs.

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