Installing a JLD Bridge Doctor in a Guild F40

In this short video I show you how a Bridge Doctor was used to flatten the top and reduce the string height on a 1970's Guild F40. This is more of an overview rather than an installation instructional video. The best "how to" video has been made my BTN Music. Here's the link: kzbin.info/www/bejne/fXqwY4yJp7KKfLM

[@gsuderman]

Excellent demonstration using the two mini squares to show the progress as you tightened the screw!

[@btnmusic9471]

Great video, David! The part where you show the two straight edges aligning is fantastic and really demonstrates how effective the Bridge Doctor is. Also, thanks for the mention - I appreciate that :)

[@flameguitars5770]

Yes, meant to send you a link to the video

[@murfbass]

I also thought it really demonstrated how methodically this guy's mind works. What a really smart way to show it working. I'm glad I found him. I watch an awful lot of these kind of videos. Don't know why I only found this guy now.

[@johnmagee8195]

Very nice video. About 2 years ago, I used the bridge doctor on an Alvarez 12 string that was completely unplayable above the 5th fret. At that time, I could find very few videos about it, but now there are quite a few, and yours is particularly well done. Thank you! Oh, and my 12 string plays easily now!

[@jdmac44]

Nice to hear that it works out as a long term solution! I'm looking at ordering one for my 25 year old guitar that I bought while traveling overseas, that's really cheap, but has sentimental value and I do love the sound of it!

[@patricklilly2520]

Fantastic work, Thank you Sir. Nice to see someone still knows that Bone is the superior material for that application. Bravo!

[@barryjohnson2865]

You demonstrated the mechanics of Bridge Doctor clearly.

[@chuckpatch1230]

i am watching a lot of vids on this ,you nailed it my friend. i learned more from you than others especially with the squares to see your adjustment ,you are a great teacher thank you.

[@flameguitars5770]

Thank you

[@musicmann1967]

I have no doubt whatsoever that this is exactly what my Guild 12 string needs. My only decision is whether to do the work myself or bring it to my acoustic guitar repair gal. Thanks for the great video!

[@timbennett6644]

Outstanding... Now, you are the very fellow i have been looking for. I have a Guild JF30 12 string. Dated from around 1988. I think the very same thing has happened to mine. I have been toying with buying a new one, but this guitar i have had since 89. would dearly like to get it looked at.

[@dennyps1]

Good demo on the bridge doctor 👌

[@sdmwoodworking]

Interesting video and good information well presented. I once had a Japanese Epiphone (FT-155) that had been purposely "bellied" by a luthier before I bought it. To achieve this, he had shaved the top braces behind the bridge, which indeed allowed the strings to slightly force the bridge to rotate and produce the belly. But the belly wasn't large, and the guitar's geometry wasn't distorted enough to cause noticeable problems either with a loss of string pressure on the bridge or with the action, which was typical of my favored setup - just this side of buzzing. The fellow's idea was that it might improve the sound by making it mimic an arch-top guitar. I don't know if it worked because I never heard the guitar before the modification, but it sounded good all the while I had it. I have to say that when I bought the guitar I was a bit concerned about the heterodox modification and the sort of problems shown on the video, but the Epi wasn't very expensive and I liked it. I owned the guitar for probably forty years, and I don't think the belly increased very much at all in that time. It was still perfectly playable and still had quite nice sound when I finally sold it - for (I think) about twice what I originally paid, not counting inflation. (Yes, I told the buyer all about the modification before we made the deal. He's a dealer and priced the guitar at what others of that model were selling for at the time.) I bought another Epiphone - this one an actual arch-top. It's definitely above my pay grade to recommend this sort of modification, and I can imagine luthiers responding to the idea with horror. But if anyone knows of it having been done to another guitar, I'd be interested in hearing about it.

[@brianharbut4054]

Fantastic! Thankyou for that. I’ve already ordered one & watching the video has convinced me completely. Much appreciated 👍

[@geekrobot9785]

This video stood out among many other install / demo videos of the Bridge Doctor because of the right angle visual of the adjustment. I was also installing one of these on a Guild, an F-30, and was apprehensive about adjusting the grub screw / rod tension. But your video shows you likely need it tightened a few turns beyond hand tight, which corroborates the direction in the JLD installation instructions for instruments with a bellied top. I also adjusted it about halfway to flat the first time, and then further tightened the tension rod 24 hours later, until my 2 straightedges on the top and bridge were as close to parallel as possible without getting tightness in rod adjustment screw.

[@robertbernardo783]

Thanks for this clear and informative video. I need this for my guitar, but I am going to let a professional install it. My Washburn D-100M's bridge has a small space between the D and G pins, and I'm not confident about drilling a hole there. Thank you again.

[@carlbussmann7559]

excellent video with explanation.

[@dadlaponizil3687]

Hopefully this is a one off experience. I just installed one of these and it did a fine job of leveling the top. But it also introduced a vibration/resonance at the low end. So when striking the low E string, the sound would not be clean but coupled to/with a vibration. I know it was because of this additional attachment to the top because when dampening the bridge with my hand, the sound was clean. I had to remove the Bridge Doctor and the sound was clean. So I think that proved it. I did a lot of work to figure this out. Perhaps you should let people know that when you attach additional mechanical members to a vibrating membrane, you may introduce additional resonance masses.

[@Mikee535]

Just what I needed to see! thank you.

[@flameguitars5770]

Glad to help

[@ajaygodase]

Great video... Parallel edges was best part

[@flameguitars5770]

Thanks. Yes, the parallel edges show how effective the Bridge Doctor is

[@JonDeth]

*For $29.95 + tax and shipping, it's finally a reasonably priced product from Stewmac lol.* I had an acoustic that could have used this close to 30 years ago, but it held up until the bridge I had milled so dangerously thin split in half.

[@mandoanne9466]

I don’t see any comments on here about humidity, or lack, which is what causes these problems to begin with. I live in the high desert in New Mexico. Relative humidity usually in the teens and 20’s. I forgot to humidify my guitar (mostly because I now play more mandolin), and here’s my “diary” of healing my guitar recently: Yamaha FG-335E (acoustic with electric pick-up) 1/25/2023 Brad & Luther looked at my Yamaha guitar & suggested Galen take a look. 1/27/2023 Galen took a look and said my guitar is begging for humidity and it’s about to explode if I don’t do something immediately. I humidified it that night. He said soak a towel and put it in a plastic bag in the sound hole and in the case for a month! He said my Yamaha is top-of-the-line for the year it was made and deserves a really good effort. I put 2 small bowls with a soaked sock in each one, with a drop of frankincense. Covered the sound home with a plastic cover and locked the case. 2/1/2023 added more water to bowls. 2/9/2023 added more water to bowls. 2/10/2023 added cutting boards at bridge end to add weight per Galen’s recommendation. He recommended a telephone book but I wouldn’t be able to close the case so I used small cutting boards. 2/17/2023 added more water to bowls. 2/21/2023 Galen inspected, measured, and said he sees improvement. He showed me how the wood shrank and the frets didn’t, and are sticking out. But he said it’s progressing nicely and needs more time humidifying. He said when I put new strings on, don’t use first string with diameter any higher than .11. The others will be .14, .22, .38, etc. He suggested looking at KZbin video by Bridge Doctor. Might need to drill a hole as he did with his guitar, to put like a truss rod similar to the truss rod inside the neck, but at the bridge end. Added more water to bowls at home and replaced cutting boards.

[@BreadLightPray_EWFMgtr]

thanks ❕ i have a few cedar top guitars that don't seem to do well in the more damp climate , bridge ungluing , belly lifting ; are small builders making cedar tops too thin ❔❓😕

[@theguitarincharge7876]

hi there that was nice.. there's no available here in the phillippines.. will you please defined what materials need to make a DIY like JLD bridge doctor? TIA

[@jamescassidy4045]

I’ve got a 1960’s acoustic that’s beautiful, and I’m quite sure it will need a Bridge doctor unless I spend hundreds of dollars fixing it, but just curious, the belly rise isn’t actually too too bad, and the action is not too bad, it feels quite playable still, and tuning wise is not bad, but has this one bad quirk. If you tube it in tune with itself, as soon as you press the low E string on any fret, it goes very sharp. Does anyone know what might have a role in causing this? The rest of the strings seem to be fine, in the sense none go super out like the low E when fretted. They still have some issues, but nothing like the E.

[@anthonykenny1320]

Can the nylon mounting post be relocated into one of the three 2 mm holes The instructions that come with the unit are hopelessly inadequate and vague

[@joq702]

10-25-22 Tuesday - Question - if using the brass pin method, I can see the attraction because of no drilling, but my chief engineering preference is that the bridge doctor be evenly installed in the middle so that the upward pressure on the front edge of the bridge is applied as evenly as possible to the bridge. Because the middle of the bridge is technically between the 3 and 4 bridge pin holes, would not the choice of the brass pins mean that there is a slight offset in where the wood block sits on the underside? Does this long-term mean one side of the bridge is getting more upward support (even if incrementally) than the other side? My concern would be that over time this would or could cause a slight twisting in the bridge or more bellying on one side of the top? Maybe it means so very little that is not worth a concern at all. I thought I would ask as I am sure that others possibly have the same question.

[@neilfromclearwaterfl81]

JO Q - I thought that over too however the mechanical designer in me took a step back and reflected on whether the center of stress/moment truly is between the two middle strings and the answer became obvious that it was not but was slightly towards the bass side where the much heavier wound strings are located. I went with the brass pin model and it corrected the bulge which was horrific due to high levels of humidity which had resulted in more of a ski jump between the bridge and the neck. I was also concerned that due to the severity of the bulge that the tapered head of the flat head screw would act as a splitting wedge and eventually crack the tail of the bridge off from the extreme stress that would be required to correct things. Back then there was no brass insert in the nylon mounting post so it stripped out from the force required to even start correcting things and after a call to JLD (the owner spoke with me personally) we determined that a brass threaded insert would be required inside the nylon post to handle the stress. I modified the nylon post adding the brass insert myself per JLD's instructions and it took several incremental adjustments to gradually get all the bulge out. Now the guitar top is nice and flat and I've adjusted the string height so that the 1970's Fender version of the D35 plays almost like an electric. The Fender D35 was made to even out the tone so that the bass strings didn't drown out/muddy the mids and trebles like the Martin which the brass pins enhanced beautifully though I did have to enlarge the string holes in some of them to accept the Phosphor Bronze Heavies I prefer. If ever I find that the Bridge Doctor is no longer required I can simple remove it leaving the guitar in OEM configuration without any extra scars, holes or plugs left in the bridge. The Bridge Doctor has been no problem and has held up fine for over a decade now. Best!

[@braderrick]

Nice video and thanks for sharing. I’d like to ask though, should all of that adjustment be made at one time like that? I didn’t know if it was something that should be done gradually over time tightening that screw or all at once. Maybe over a few weeks? Months? (It’s my guitar by the way so timely repair is not an issue). Just wondering what your opinion is on this. Thanks!

[@flameguitars5770]

Yes, that's a good point. The Bridge Doctor is reversing a process that may have occurred over many years. So gradually tightening the screw over the course of a week may be a wise precaution.

[@anthonykenny1320]

Too bad you did not mention the size of the drills used and how do you get the tensioning rod into system block Did you remove the Allen key I have a 1982 guild 12 on which the bridge is so tilted that the tension rod will not be parallel with face but tilted up at the tail block is there any way of overcoming this issue

[@DougHinVA]

The wooden dowel has its tapered end press against the end block inside the guitar. That end is NOT cut off...

[@nokrimchimarak1246]

what if it break when you tight it

[@Atrejo155]

Awesome video ! I’m planning to instal a bridge doctor on my takamine 12 and 6 string guitars , also what drill bit size is good for the hole ?

[@flameguitars5770]

Thanks. You need 2 drill bits. One for the bolt hole and the other for the plug that sits over the bolt. I suggest you look at the JLB instructions on their website for drill bit sizes.

[@GuitarNTabs]

Thanks for doing this video - I enjoyed it! 😊 I don't know if you know.. I can see a Screw mount version, and a brass pin mount version.. What's the difference? I hope to see more repair and luthier videos again soon - you're great at your work! Best regards.

[@flameguitars5770]

Thanks for your comment. Yes, strictly speaking I have installed the Bridge System rather than the Bridge Doctor. The Bridge Doctor has 6 brass pins which are fitted through the string pin holes. One of those pins connects to the internal block system. The ball end of the string is secured to the top of the pin rather than through the string hole in the conventional manner. (hope that makes sense! Could have explained it better)

[@GuitarNTabs]

@@flameguitars5770 - Thanks for the reply, I appreciate it 😊 Aha, I see! It looked like that to me as well, but I wasn't sure, and the webpage didn't clearly state that.. I'm following, and that's a nice option as well! Thanks for taking the time to reply! Best regards.

[@nikos4828]

Great video thanks to you I understood how it works. Great music too, can you give us the name of the song and the author, please ?

[@flameguitars5770]

Thanks. I think when I made this video I was using free music from the KZbin audio library.

[@grahambambrook313]

Quite a neat trick but does it not affect the resonance of the sound board? It must, surely.

[@venko3211]

Jld bridge Dr system reduce the guitar bright sound?

[@stevewiggins1971]

I just installed one in my 1973 Yamaha fg75. Approximatley how many turns did you need to gibe the set screw to flatten the bridge. I turned and turned many times and it only seemed to pull the bridge down a little. I'm a little afraid to keep turning it.

[@flameguitars5770]

Steve, once the rod is under tension, and then as you begin to tighten the set screw, you should start to see the bridge move immediately. In my experience the BD only works where the bridge is tilted forward. If the top has raised over time but the bridge has not tilted towards the sound hole, then the BD may have little effect.

[@cmcguitars]

One tip, once you start tensioning the dowel screw you can also slide the end of the dowel that’s touching the tail lock down towards the back of the guitar. This will give you a little better angle and will apply the force a little better, particularly if the bellying is extreme. The closer you can get the dowel to 90 degrees to the tail block the better. In an old JLD instruction it says to lightly tighten the screw and then slide the dowel down. Once you get the dowel to 90 degrees you can always tighten more if necessary.

[@tps1020]

It won't work on a guitar with a narrower body like a Takamine EG560C. It wouldn't fit so I kept cutting it down to the point it fell apart.

[@user-wr9pk4lu8s]

Thankyou for the explanation very good and not rushed, my 12 string Epiphone I bought back in 1975 travelled all over with me and went to Italy with me just short of a year when i was 20 yrs old (68 now)just traveling around, unfortunately it got this belly bow behind the bridge about 30 years back, totally unplayable, action far far to high took it to a guitar chap who said the whole guitar needed to come apart and have new braces fitted and would cost more than the guitar is worth, as you can imagine I was quite unset but kept it and still have the guitar topass onto my son, do you think this bridge doctor contraption should fix it and is it something I could do myself or get a guitar tech to do?

[@flameguitars5770]

Very hard to say without seeing the guitar. The Bridge Doctor is most effective where the bridge has started to tip towards the sound hole. When the BD is tightened this tip of the bridge is reversed and, as it does so, the overall height of the top is lowered. There are various videos that show how to install a BD

[@user-wr9pk4lu8s]

@@flameguitars5770 thanks for your quick response, I will have to investigate a bit more.

[@lindsaythompson726]

How in the world can you tell what you're doing when you can't see through the sound hole? Just by feel?

[@neald72]

If there is a gap under the bridge sue to the belly, how do you reglue it? It can't be done before because of the size of the belly, and it can't be done after because the doctor is fixed permanently and you can't reglue a bridge with the doctor on! Help!

[@andrylahem8818]

mantapp

[@miketaylor4993]

does the jld change the sound of the guitar? better or worse or no change?

[@flameguitars5770]

Hard to say. But Breedlove used to fit something similar on their guitars, arguing that it improved the tone and projection of the guitar.

[@alexng3375]

Will that affect the tone of the guitar coz the top is not moving freely?

[@flameguitars5770]

Possibly. But then if you have a guitar with a very high action it might be worth taking that risk to make the guitar more playable. That said, Breedlove Guitars used to fit something very similar on their guitars. They called it the bridge truss system, and claimed it improved the tone of guitars.

[@matrox]

No need to have removed the bridge and reglue it?

[@lesliel1182]

What is the story here, not all guitar bodies are the same width, so how can this work?

[@guitartec]

Once a Bridge Doctor is fitted, tone-wise, it acts similar to a sound post in a violin giving the instrument a more overall complex tone. It does this because the back and sides, which usually are mostly reflective, now have sonic vibration routed to them through the bridge truss, ie, the guitar's soundboard vibrates through the truss's sound post to the guitar's tail block, which in turn, makes more of the sound box vibrate. You can feel this when strumming. Sometimes, this complexity is misunderstood as a quieting of the guitar's overall volume, but this is not really what's happening.

[@flameguitars5770]

Thanks for that comment. Breedlove guitars install a similar device to some of their models and I believe would argue that, as well as ensuring that the body top does not distort, there is an improvement in tone and projection.

[@guitartec]

@@flameguitars5770 Actually, I bought a Breedlove C1 in quilted maple back in 1996 that I had talked to Steve Henderson at length before I sprung for it. This is where I learned about the JLD Bridge Truss. After getting to know Larry Breedlove and several luthiers there, they are the ones that explained to me how it works sonically, and I found out there was mixed feelings about the use of the truss. Many there felt it robbed their guitars of volume and/or tone. Of course, back then all Breedloves were built around the truss and braced very lightly b/c the truss would carry most of the top load. This is quite different from retrofitting a bridge truss into a normal X braced guitar with a belly issue. I think in this case, a truss almost always makes a lesser expensive guitar sound richer- maybe not the Guild jumbo you were retrofitting, but Yamahas and similar quality guitars. Breedlove is no longer the same company as they are owned by Bedell these days, but many of the old crew were not big on the bridge truss for the reasons I spoke of.

[@flameguitars5770]

@@guitartec interesting insight. Shows that there is not just one view on this matter.

[@guitartec]

@@flameguitars5770 I agree. Thanks for posting your video.

[@nicktrousers]

Interesting point there. I have no personal experience with hearing a guitar that has had a bridge doctor installed so i was always apprehensive. But it really seems like its probably the best solution to give some guitars a second life. I have an old eko 12 string that has quite a belly. And although its got a bolt on neck and you can adjust for string height quite easily that doesnt fix the bellying problem. Although 12 strings are another beast of their own. But comparing the doctors to a violins sound post makes quite a lot of sense. And seeing the doctor work really well in this video makes me think i dont give it enough credit.

[@khoirilkanza9367]

Brapa cm tinggi kayu nya pak

[@bleufishtv]

Will the bridge doctor be able to be taken out ? Or is it there permanently

[@flameguitars5770]

It can be removed if you so wish

[@Gio2p]

5:03 Who else blew?

[@bao5413]

This is weird...not saying you did anything wrong but your method of checking for a titled bridge is not how I would do it. Most bridge surfaces nowadays, especially taylor, are titled at an angle straightout of factory (I have a brand new taylor and it’s titled the exact same way as shown in the video). Even the one in the video has a designed angle to it...So if someone isn’t aware of this they may think their bridge is lifted and required a fix. Check with a ruler, place a long one behind the bridge to check for bulge, a straight ruler infront of the bridge aligned with the fingerboard to check for collapsing top around the soundhole area..

[@duzntconcernya8837]

*tongue click* NOIIIIICE

[@jimgeorger4452]

Other than showing hands inside the guitar, how do you adjust the length of the dowel? How do you avoid the string pins? Do you simply crank the screw til its level or do it over time? This seems like an over simplified advertisement for the product.

[@benfordguitars]

The dowel is oversized. You remove the set screw. Insert the dowel till it hits the end block. Mark the dowel where it exits the front of the BD. You cut the dowel 1/8" short of that mark. Insert the dowel and screw back in the screw insert. If the belly isn't to severe you can adjust it all at once. As a safe practice I do it slowly over a few hours/days until its where I want it. Without strings of course. The guitar usually takes years to develop a belly. I dont think its a great idea to crank it back in place in a couple minutes.

[@enricodelre284]

Reggerà ?

[@46peto]

Para que sirve eso ? 🤔

[@LuisJimenezr01]

A las guitarras se les hace una panza con el tiempo y hace que las cuerdas estén muy altas así que se utiliza este aparato para ponerla plana.

[@46peto]

@@LuisJimenezr01 gracias por responder saludos desde URUGUAY 🇺🇾

[@theseventhjournal7957]

Why not use epoxy

[@giopereperez4532]

Have you ever heard of someone installing one a 12 string on the g string with a pro pin or is the person wrong and doesn't know how to install it

[@theseventhjournal7957]

Lol

[@kowal767]

Hi guys, why you paying 50 bucks for tool like this. I made this my self and cost me 2 bucks just for stick and working perfect.

[@glenncater1]

HOW DID YOU MAKE IT BROW ? SOME IDEAS PLEASE !