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Guitar Bridge Doctor, My Take

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Project by anthm27 posted 05-12-2020 07:40 AM 911 views 1 time favorited 16 comments Add to Favorites Watch

Ok so I am certainly no Luthier but as someone who is re learning guitar I have a keen interest in the instruments.
I would love to hear from some of the guitar experts on this one.

A bridge doctor is a permanently installed device inside an acoustic guitar. It is screwed to the underside of the guitar bridge it then has a dowel that leads to the guitar end perimeter. It is then tensioned and using like a cantilevered force it brings the bridge back down so the top of the guitar is nice and flat. (if your not bored yet read on for the full story)

On my new guitar the action seemed to be getting worse and worse, I called a friend of a friend here in Hong Kong who is an expert in everything guitar including guitar set ups , his name is Vern and a link to his Facebook page can be found here.

Vern explained that guitars are unusual in the sense that the exterior is normally finished with polyurethane but the inside is left bare wood to enhance sound quality. The problem with all that is when the inside of the guitar gets moist due to air humidity it can distort the face of the guitar. Basically the guitar top gets moist, expands and distorts by pushing outwards, this effectively brings the strings further away from the fret board.(the action) All this particularly prevalent in Hong Kong’s moist environment. Vern went on to explain in my case i need to reduce humidity and timber moisture content inside my guitar.

A couple of days later he messaged me and said that his 12 string acoustic guitar has a similar problem in that the bridge is distorting outwards and that he knows of a device called a bridge doctor. What a bridge doctor does is bring the distortion out of the guitar top and reduce the action. He then went on to ask if I could make him one off these devices.

Anyways all as clear as mud, Plenty of you tube videos can be seen on the subject.

This is my take on the guitar bridge doctor device. Below some pics of the build, For strength I Laminated two 1/2 inch thick pieces of walnut. I had to chisel out for a nut then covered it in epoxy for the tensioning threaded rod to screw into. I drilled out the 3/8 locating dowel so it effectively a packer only.

-- There is no hope for any of us if we keep apologizing for telling the truth.





16 comments so far

View robscastle's profile

robscastle

7753 posts in 3221 days


#1 posted 05-12-2020 08:39 AM

I have absolutely no idea on this subject but understand the physics of it all, ... a bit like veneering one side of a timber item and not the other.

Also no doubt having a item under tension all the time doesn’t win any friends either.

So I rang my “mate” Brian Adams for some expert advice, I explained to Brian what the problem was but he was actually a bit rude said he didn’t know who the falk I was and hung up on me!

Undeterred I then went looking for an instrument he owned back in 2015 called the “Reach out to Asia” which I thought I could buy you for a practice guitar.

I managed to track it down, Its owned by a a lady called Her Highness Sheihka Miyyassah Al Thani so I gave her a call and offered her $1500 for it but she politely said it was not for sale.

So next I decide to make some more international calls, rang Chuck Berry and Jimi Hendrix because I remembered the were good players and would be able to help out, but their phone just rang out, god knows where they were!

Any way get that doctor inside and see how it goes. Dont be surprised though with big seasonal changes pre tuning before playing may still be required anyway.

-- Regards Rob

View LittleBlackDuck's profile

LittleBlackDuck

6588 posts in 1837 days


#2 posted 05-12-2020 08:51 AM


..... I would love to hear from some of the guitar experts on this one….
- anthm27

antman, occasionally when I have a smoke I speak with Jimmy..... on my next trip, I’ll give him your phone number…

OOPS, didn’t realise rc already spoke to him… sorry antman no can help then… My original Fender was traded in for a cask of vino… back in ‘67…

-- If your first cut is too short... Take the second cut from the longer end... LBD

View HokieKen's profile

HokieKen

16750 posts in 2155 days


#3 posted 05-12-2020 05:47 PM

I have no idea what any of those things are Anthony. But you obviously made a solution where you didn’t have one so well done!

Now let’s have a video of you, Rob and LBD doing “I Come from the Land Down Under”

-- I collect hobbies. There is no sense in limiting yourself (Don W) - - - - - - - - Kenny in SW VA

View Foghorn's profile

Foghorn

1060 posts in 403 days


#4 posted 05-12-2020 07:33 PM

They are commonly used to fix a bellying issue such as you describe. As long as there are no loose or cracked braces, they are a lot cheaper fix than pulling the top and re-bracing. Some manufacturers such as Breedlove install them on their factory guitars. I would suspect that is to minimize warranty issues. Some claim a negative effect on sound while others don’t. I’ve never tried one.

As far as finishing the inside of a guitar, the main reason is to allow ease of future repair where a crack may need to be cleated etc. The effect it makes on sound is strictly subjective. Many top builders such as Bob Benedetto routinely finish the inside, usually with shellac. Finishing the inside also has little to no effect as a result of humidity changes due to the very thin wood used on guitars. Nice job making a StewMac Bridge Doctor! https://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Bridges/JLD_Bridge_Doctor.html

-- Darrel

View anthm27's profile

anthm27

1804 posts in 2127 days


#5 posted 05-12-2020 10:32 PM

As far as finishing the inside of a guitar, the main reason is to allow ease of future repair where a crack may need to be cleated etc. The effect it makes on sound is strictly subjective. Many top builders such as Bob Benedetto routinely finish the inside, usually with shellac. Finishing the inside also has little to no effect as a result of humidity changes due to the very thin wood used on guitars.

- Foghorn

Thanks Daryl for the comments, Nice to get an experts point of view. Very interesting about finishing on the inside of the guitar, I guess for mass guitar producers it is certainly cheaper also not to finish on the insides.
Im thinking at the moment for a guitar that is going to be used in a Tropical Humid type climate to may be build it with a bridge doctor installed and shellac on the inside from new.
I perused some of the guitars you have built, very nice work.
Thanks again.
Regards
Anthony

-- There is no hope for any of us if we keep apologizing for telling the truth.

View mikeacg's profile

mikeacg

1850 posts in 2074 days


#6 posted 05-12-2020 10:58 PM

Anthony,

Never had the need for one of these but I’m pretty sure I’d never get my big paws inside the sound hole to properly install them either! Good to see you taking this whole guitar thing so seriously! I can’t wait to hear you play sometime!

Mike

-- Mike, A Yooper with a drawl, http://www.artcentergraphics.com

View robscastle's profile

robscastle

7753 posts in 3221 days


#7 posted 05-13-2020 01:53 AM

Hey Dave may have some good info on the internals, might be worthwhile giving him a call/PM

and Boo Hiss all my jokes got ignored …rats!!!

-- Regards Rob

View anthm27's profile

anthm27

1804 posts in 2127 days


#8 posted 05-13-2020 04:45 AM



Hey Dave may have some good info on the internals, might be worthwhile giving him a call/PM

and Boo Hiss all my jokes got ignored …rats!!!

- robscastle

Cheers Robbo, oh and don,t worry, I got a belly laugh out of your humor.
Brian Adams told me that you called, and I was surprised Jimi Hendrix number didn’t divert to mine.
Cheers
Anth

-- There is no hope for any of us if we keep apologizing for telling the truth.

View anthm27's profile

anthm27

1804 posts in 2127 days


#9 posted 05-13-2020 04:46 AM



Anthony,

Never had the need for one of these but I m pretty sure I d never get my big paws inside the sound hole to properly install them either! Good to see you taking this whole guitar thing so seriously! I can t wait to hear you play sometime!

Mike

- mikeacg

Cheers Mike,
Mate yer taking it seriously I get Skype lessons form a London based Guitar Teacher once or twice a week.
Still Loving it,
Regards
Anth

-- There is no hope for any of us if we keep apologizing for telling the truth.

View anthm27's profile

anthm27

1804 posts in 2127 days


#10 posted 05-13-2020 04:51 AM

To Loyal fans Kenny and LBD thanks for looking in. Yes we do need a video from the ”Land down under”. by the Band ”Men at Work” so so good, it brings back memories of my miss spent youth.

For those that don,t know what we talking about, check this.
https://www.youtube.com/watch?v=XfR9iY5y94s

Love it.
Regards
Anth

-- There is no hope for any of us if we keep apologizing for telling the truth.

View LittleBlackDuck's profile

LittleBlackDuck

6588 posts in 1837 days


#11 posted 05-13-2020 08:50 AM


.... miss spent youth.
- anthm27
antman, if you’re talking about spent on a miss... hell I’m still paying for it.

I did my guitar phobia in my youth… while I still knew what to do with groupies.

-- If your first cut is too short... Take the second cut from the longer end... LBD

View Grumpy's profile

Grumpy

26811 posts in 4868 days


#12 posted 05-15-2020 11:45 PM

Good one Anthony.

-- Grumpy - "Always look on the bright side of life"- Monty Python

View Dave Polaschek's profile

Dave Polaschek

6908 posts in 1599 days


#13 posted 05-16-2020 02:19 AM

Nice solution Anth. My solution to humidity making guitars sad is solid body electrics, or an acoustic made of steel but my tastes aren’t everybody’s. Be well, buddy!

-- Dave - Santa Fe

View anthm27's profile

anthm27

1804 posts in 2127 days


#14 posted 05-16-2020 02:47 AM


Nice solution Anth. My solution to humidity making guitars sad is solid body electrics, or an acoustic made of steel but my tastes aren’t everybody’s. Be well, buddy!

- Dave Polaschek

Hi Dave
Thanks for the post,
I hear you on the solid body electrics. The steel acoustics is a new one for me, very interesting.
Hows the sound on those acoustics?
Id be interested.
Regards
Anthm

-- There is no hope for any of us if we keep apologizing for telling the truth.

View anthm27's profile

anthm27

1804 posts in 2127 days


#15 posted 05-16-2020 03:01 AM



Good one Anthony.

- Grumpy

Cheers Tony, you never miss a Daily Top 3,
Thank you
Regards
Anthm

-- There is no hope for any of us if we keep apologizing for telling the truth.

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