Official Luthiers Forum!

My turn: Clearing the finish completely under a bridge leaves absolutely no margin for error if and when the bridge needs to be serviced in the future because it's lifting or splitting..... or the saddle slot has split with the saddle tipping forward - all things that can commonly happen, especially the bridge lift. I'll add that other common causes of bridges lifting are bridge plate damage between the pin holes from using cheap, slotted, pl*stic pins effectively creating a crease from hole to hole and distorting the top surface under the bridge so that it's no longer flat and the glue line gives. A dry guitar, something that we see in the hundreds starting right about this time of year with the woods expanding and contracting at dissimilar rates also stresses glue lines and can cause a bridge to lift. Another cause that comes to mind are radiused tops that have had a flat bridge "smashed" on top with lots of clamping can give too in time even if the manufacturer uses nylon pins not only to locate the bridge but as a hedge against bridge movement in time. Nylon pins are more commonly used in production than you might think as well. Even some of the top tier small builders use nylon pins.

As such bridges need to be serviced in time like it or not and some repair person like me may have to be inserting a pallet knife in-between the top and bridge on one of your creations. Flakey finishes, too much heat in the glue softening process causing finish to bubble, not reading top run-out properly are all common reasons why if there is NO margin for error with the "cosmetic boundaries" of how a bridge is glued on the repair may show OR require unnatural acts to repair/touch-up finish when none of this was necessary.

Ken welcome to the world of f*ctory guitars if you are noticing that f*ctories don't clear much finish under their bridges. Not only is this an opportunity for small builders to outperform f*ctories in yet another respect it does not serve even them well when they have to pay me 7 years out to reglue a bridge under warranty.

As such regardless of who likes to clear ALL the finish from the entire bridge footprint I don't like the practice either and it clearly does not fit in well with the concept of serviceability down the road.

Going back to clearing finish under the entire bridge. Ever see cold creep of a bridge exposing a glue line or bare wood line on the back edge and lifted, mounded/plowed..... finish on the front edge - we have..... Had the entire bridge foot print not been cleared the back edge would not be something that is glaringly obvious.

For those of you who may not do repair work once bridges are removed the wings often curl and in order to get the bridge flat again some bridge height is lost on the belt sander getting the bottom flat again. This can also reduce bridge height removing material from the bottom to get to a flat state including the curled wings. Some bridge designs such as mine...... where there are NO vertical sides, ends, etc to the bridge shape removing more bottom material because of curled wings or even a curled bridge (that happens too....) WILL reduce the outside dimensions of the bridge making it smaller. If the bridge foot print is entirely devoid of finish the bridge can no longer be reused and has to be replaced. On the other hand if some finish is left under the bridge this can be avoided.

Now let's talk about how much finish is left under the bridge but before we do I'll reiterate that I once calculated up to 40% of bridge gluing surface being left under a major manufacturer's bridges that is finish that was not cleared - not......good....... especially on the back edge.

With the rabbiting that we do the amount of finish left under the bridge is a ledge that may only represent around .005" inward from the bridge perimeter. Do the math and you will see that we are still using around 98% of that 100% of bridge foot print that is available if we remove ALL finish and pocket the bridge in a well devoid of finish.

Regarding how wings can be problematic to get down and keep down that's where Luthiers have to earn our pay. With our rabbiting prior to the rabbiting the bridge is fitted to the top and this means imparting a radius if one is present and necessary. We do this so often these days that for us it starts on a belt sander using the ends of the platen where it's curved to match the top radius. Next the bridge is trial fitted and if it fits well in terms of the radius it's off to the rabbiting jig.

After the finish is cleared to around .005" from the edges of the bridge perimeter (and yes this margin for error is so very small that I have trouble even seeing it...., Dave does not....) the bridge is trial fitted again. We want the wood to wood contact to be that 98%ish of cleared foot print AND we also want the upper lip of the bridge rabbit to be sitting down on the finish ledge with NO gaps. With observation and trial, dry clamping we observe the fit and then judiciously scrape with a single edged razor blade the proud areas on the bridge bottom permitting anything sitting up where we don't want it to to sit back down and behave.

We don't rely on lots of clamping to make a bridge fit well. We want it to fit pretty well with NO clamping and then with clamping and firm clamping as well it all settles into place nicely.

Just like necks bridges need to be fitted, always!

By the way the guitar in the picture was picked up last Wednesday after being with us 2.5 days.... It belongs to an aerospace engineer and he bought it used so he could not speak to if the bridge had lifted once or more before. It is about 20 years old, he knew that much... and what likely caused this bridge to lift other than the terrible job.... of attaching the bridge either in a previous repair or from the f*ctory..... (I personally suspect previous repair mostly because of the use of "brown glue") was that this owner let the guitar dry out. The fret ends were proud, top caved, etc. all the signs of a dry guitar and he admitted same under hot lights and water boarding..... Maybe we could use HHG boarding..... but the open time is too short....

Bridges need to be properly fitted and if you struggle with getting the wings down the thing is not yet fit properly and needs more attention. In my experience properly fitting a bridge on a severely distorted top can take more time than any other operation in the removal and reglue process.

Professional standards, at least our's do.... dictate NO gaps, none anywhere ever when regluing a bridge and how one gets to that goal takes lots of experience AND lots of opportunities for experience as well. The folks who seem to do the best work here are the folks who have over time gotten comfortable with their methods for better or worse but what works for them.

Repairs are very different from building too IME because when we build we build in our shapes and know what they are and where they are. With guitar repair the top can be a very different shape than when it was built making bridge fitting more difficult.

Although this may be an academic conversation for some... this is our life, every single day we may be either regluing a bridge or one is in the wings waiting for it's turn in on the bench. As such methods are developed over time and by time I mean a decade or more so that we can see what if anything may come back or not. We have had excellent success with the rabbiting method AND we are not the first or the last either to nix the clearing of ALL finish under a bridge and instead develop a hybrid approach attempting to exploit the best of all worlds with all considerations in mind. We remove around 98% of the finish AND address the issue of a flat bridge spanning a .003 or more finish ledge where our bridges because of the rabbit make wood to wood contact immediately where the finish is cleared. A flat bottom bridge will not for some distance inward spanning the finish ledge. The thicker the finish the more wood to wood contact area is lost.

Collings guitar who IMO likely produces some of the finest f*ctory instruments on the planet uses the rabbit technique too. Even on the OLF this method is used with Terry Kennedy and several others. I used it as well once I learned it but prior to that I used the clear the entire bridge patch method. By the way clearing the entire bridge patch with black topped guitars.... was not a great choice. SO far so good but come bridge reglue time something is going to show if not touched-up.....

CNC has absolutely nothing to do with anything that we are doing or describing here. Instead we are speaking of a method that works very well even over time, is used and embraced by other pros, AND may not be for everyone because you also need to be highly skilled in fitting a bridge even to the point of using a scraper to correct a .001" variance.

Oh yeah.... let's also address going forward or that all important consideration of serviceability in time. The repair for this guitar is NOT a good example of anything when it comes to the ease of future repairs but it most certainly is serviceable going forward anyway.

Typically as Dave indicated we don't route finish off obviously because you can see what happened either by a previous repair person's hand or the f*ctory here in this example. We use very sharp chisels and are only removing old glue exposing the wood never wanting to remove any wood.

I triage hundreds of guitars annually and it's been my experience that more often than not when a client guitar has a lifting bridge they are not even aware of it unless it's an extreme case which happens too. So we point out that the bridge is lifting, grab a .0015" feeler gauge and show the client that it can be inserted under the bridge.

When a bridge lifts the pallet knives are inserted being mindful of runout and other considerations that may be specific to that instrument. With the rabbiting of the bridge bottom the bridge has already lifted...... making palet knife access simple and easy. Bridges are not typically removed because they are not lifting BTW although that can happen too if a bridge needs to be replaced because it's splitting or the owner wants a replacement perhaps to replace a bridge that was already replaced in the past with non-original woods. I recall a 30's Martin that had originally had a rosewood bridge, received an ebony bridge in the 60's and the owner wanted it returned to a rosewood bridge.

Anyway in terms of getting a pallet knife in there and the serviceability of the repair when this bridge will need servicing in the future it will likely be because it's lifting again 40 years out when all of us are worm food. Because it's lifting palet knife access is easy and no harm was done in terms of serviceability. Reading runout will be key too.

Alternatively clients may not wish to pay $500 plus for a top to be resurfaced, finish touched up, and the bridge glued on as it should have been in the past without a .035" deep hole in the top. Instead this client paid less than half this amount and also received a complete set-up, new strings, and was and is happy as a clam. And that boys and girls is pretty important to us, always!

I left out something that was brought up by another poster.

We can rabbit a radiused bridge bottom because our rabbiting jig has a radiused table. It's part of the tool's design.

Hi Tai Fu and Happy Holidays to ya!

To my knowledge Taylor does not and has not ever rabbited their bridges. I suspect that what you may have observed that looks a lot like a rabbited bridge bottom is the old glue that builds up near the finish termination line. Remove this old glue and you can see there is no rabbit nor was there ever one.

I most certainly could be wrong and often am.... but to my knowledge Collings is the only f*ctory producer of guitars that is currently or has in the past done this rabbiting technique. I wish that we had posted a pic of the bridge bottom as it came off because that one looked like it was rabbited too and I even asked Dave if this mystery producer was known to rabbit their bridge bottoms because I too initially mistook the glue build up at the finish ledge on the bridge bottom for a proper rabbit.

You've said before when you were repairing in Taiwan that you often are working on inexpensive, Asian instruments which are well known for super thick, dipped.... in appearance finishes often polyester as well. We work on what ever comes our way if it makes economic sense for all concerned and at times even when it doesn't if the goal is to help someone regardless of what we might have to do. So I can relate.

Most of what we work on though are instruments that have some value in the greater sense, major manufacturer, high initial cost/price, etc. although again making folks happy can override this. I installed a $200 pup in a $150 Keith Urban....... POS a couple of months ago.....

Some of the things that you commonly describe as being troublesome for you are things that are troublesome for anyone finding their own way in the trade. This was certainly true for me and I often ask Dave to hold me out there as an example of his teaching chops because if I can be taught this stuff anyone can....

It's the holiday season and lots of us are trying as we might to not only do things a bit differently in terms of favoring good will over ill will and I'm certainly no exception either. Even at nearly 60 years old now I would like to think that I too can learn new tricks.....

With all of this said some of the struggles that you frequently describe on this forum are things that you could be helped with greatly I am sure. I had the advantage of having a Master Luthier mentor, a guy who has taught Lutherie professionally, worked at one of the top three shops in the US and who has built hundreds of successful guitars. Not everyone has the advantages that I am very fortunate to have had.

My suggestion to you is to get next to someone who is successful with Lutherie, makes a successful living with Lutherie and do what ever it takes to be permitted to hang-out and learn. That's what I did. For me it all started with the self admission that I have a LOT to learn and a sincere desire to give respect where respect is due and stifle myself and simply learn from the best. If you are the sort who values instruction, after all you are going to university IIRC so you must value instruction and also acknowledge that none of us can know it all consider spending time learning more from someone accomplished in the trade.

I also would like to extend a sincere invitation to you to come out to Ann Arbor and spend a day with us. It might blow your mind to see what we do and how we do it. It also might blow your mind to see professional Luthiers actually making a decent living at this and being thanked over and over again by some very grateful clients. Our clients even bring us gifts, give us tips, buy us lunch, bring us donuts and we are not even cops....

If you can ever arrange to fly out for a day we would love to show you what we do and how we do it.

Happy Holidays!

I'll have to find some time... even getting a few days off at Walmart is hard because my store is short staffed, and holidays are busy as ever. I may be able to request a few days off during the summer months to do this because it is relatively quiet during the summer (no holidays except for the 4th).

However I'll need to find some extra money to buy the airfare, which will no doubt cost around 300 bucks both ways. I'll also need to figure out lodging and also transportation as well. Can you PM me the details?

I spent an hour or so at Frank Ford's shop, and I did learn a few things from reading his site but not really any direct mentorship from him. I did have a couple of grateful customers in Taiwan who even took me out to eat right before I left, and gave me a few things like tools (some bridge clamps which is very valuable) and a factory pyramid bridge.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Actually Pat the original premise of this post was more like "look what some hack did to this nice guitar....."

A pocket that removes top wood when it was not necessary.... exposes end grain in the top wood and leaves stress risers where the top wood has been cut through, IIRC Al C. addressed this nicely in the currently running thread about WRC tops and scoring finish.

The resulting risk is more top distortion in time which, by the way is a common reason why bridges can lift..... as we see here. We didn't pull this bridge because it's rerun season for the Kardashians.... instead it decided to lift on it's own.

Happy Holidays!

By the way as for the Taylor's bridge rabbet. I remember there was a pronounced rabbet in the bridge as well as the smaller footprint in the finish when it came off. It was actually not that difficult to take it off because Taylor uses Titebond (the glue turns to jelly if it gets warm)



Here, I found an old pic of that repair I did, you can clearly see the rabbet and the lighter finish (that sat under the bridge), as well as the cut in the bridge itself. I know what I saw because Taylor's finish is tough enough to withstand a nuclear war, and the glue is nowhere near that tough.

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Summer is the best time for us too because we slow down with the 50,000 students in our town many of who leave in the summer. We are still busy enough though even in the summer so we will have one day to spend with you if you think that this would be helpful. I would also suggest that perhaps you make a list of things that you want assistance with and we can drill down with the subject matter that you find most needed or interesting.

All you have to do is get here and get a place to stay for a night or two. If you want hotel recommendations I can help with that too.

Regarding the Taylor picture that you posted I'm not sure if this bridge had been repaired prior and that the previous repair person did not do the bridge rabbit. I don't know Taylor to rabbit bridges and can't tell from your pic if what we are seeing is a wood ledge or a glue ledge.

Regardless look at all the gluing surface that they did not exploit and use..... I see the nylon pins too that I spoke of and I am wondering if this is a GS mini? The GS minis which are very nice guitars have a rather profound top radius and having regaled bridges on them before we suspect that the profound bridge radius combined with a flat bottom bridge are contributors, along with abuse and letting an instrument dry out or get too humid contribute to the bridge lift.

One more thing since I can't shut the hell up..... In our neck of the woods students can work at Walmart or Costco. Costco pays around twice what Walmart pays and it's not unusual for a Costco student employee to be making over $20 an hour in only several years.

I'm a student of how businesses run and why they are successful or fail. A life long student of this as a matter of fact. I was trained to run corporations.... and as such am always being asked for advice from the corner gas station owner who asked me about the economic outlook for the next several years to consulting gigs to help a company grow and succeed.

I read that Costco stores are roughly twice as profitable than Walmart stores per every square foot of retail/wholesale selling space. Surely there are lots of reasons for this but when comparing Costco and Walmart Costco is a shining example of the fact that a company can be very good to their employees, pay a living or better wage AND still realize significant economic success in the marketplace. Pretty cool!

Maybe if you have a Costco in Austin get an app in there?

"To my knowledge Taylor does not and has not ever rabbited their bridges."


?????

Do they David, I certainly could be wrong? Happy Holidays to ya too!

I don't believe I've ever seen a factory rabbeted Taylor bridge, although Tai's photo certainly seems to show one (albeit grossly dissimilar in size to the finish cut). Any idea what year this model is from, or does anyone else have notes or observations on when and where they've seen this on Taylors? They certainly didn't used to do this.

_________________
Eschew obfuscation, espouse elucidation.

Looks like a mask to me

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

Everyone I have seen or received has a rabbet. I wish they would send out replacements without it so I could make one that was smaller.

If everyone was making a well fitting .005" rabbet I don't think there would be much discussion. Unfortunately that's not what seems to be going on out there. Of course there is no shortage of severed top fibers by those scoring around the very outside of the foot print Either.
So many ways to screw up.

Happy Holidays to you too Hesh!

How odd that I don't recall ever seeing or noticing such rabbet in Taylor bridges here (that being said, we probably do one Taylor bridge reglue for every 10-20 Martins here, probably just reflective of overal ownership in our regional market). And I have to point out that I think Hesh's listing of .005" was probably a typo. That's about right for average depth, but the inset of course moves the decimal one place to the right (~.030-.050"). That cut in Tai's photo appears dang near 1/4"!

_________________
Eschew obfuscation, espouse elucidation.

Thanks David, much appreciated. We are not seeing the rabbits so I am wondering when it started and this may be a question best for Taylor but who really cares. I'm curious so I will give them a call tomorrow and ask and let folks here know what they say.

Dave C. tells me that I got the inset wrong on our rabbiting jig, it's .050" not .005" so sorry about that too. To me .005 and .050 look the same, I can't see either one of them..... Blind Mellon Luthier here.....

Nonetheless you can imagine how a .050" inset leaves WAY more bridge bottom in direct wood-to-wood contact than what we are seeing in say Tai Fu's pic of the Taylor. We always see bridge reglues as an opportunity to expand the gluing area and have the repair be structurally superior to the original construction short of clearing finish to the perimeter of the bridge.

I know that lots of folks don't like sunburst instruments but I've never been one of them and I love say a vintage G*bson burst with the black upper shoulders. Anyway a bursted instrument is another example of why clearing finish to the bridge perimeter can be problematic. The maker may be able to pull it off, I did several times, but the repair person is one finish chip away from ruining their day and possibly the client's ax if they don't know how to recover from the mishap.

Ken C. kind of reminds me of the Easy Bake Oven..... Taylor makes it all look way too easy and this is likely the future of most mainstream, production instruments. The machines don't complain, never want more pay, you don't have to worry about it getting too drunk the evening before, etc....

Wonder what that cost them.......

Interesting. I had to go out to the shop and rummage through my bridge box out of curiosity.
I found one factory replacement that has no rabbet. It has a note I wrote on it that says,"old style, pin holes .100" forward from new"
Maybe they began the rabbet when they moved the pin holes back.

Thanks David F.

I just sent this to Taylor and will let folks know what they say. It is the holidays and I am not sure if Taylor does what our local auto plants do and that is shut down for a couple of weeks over the holidays so the reply may take a while and the contact may need to seek a Taylor manufacturing engineer for the answer. His name is redacted to protect his privacy obviously:

"Hi ***** and Happy Holidays to you my friend!

Could you please shed some light on something for us that we would like to get right going forward if we currently have this wrong.

Does Taylor rabbit the underside of their/your bridges so that the ledge sits on top of the finish but the bridge rabbit permits the bridge bottom to have wood-to-wood contact all the way to the finish ledge? I know that Taylor rabbits tops to make them thinner around the edges but I can't recall for sure if you rabbit bridge bottoms.

We are having a gentleman's disagreement in so much as we recall not seeing this in the past and others recall seeing it.

If Taylor does do the bridge bottom rabbit did Taylor always do this? If not when did it change and is it done on all models?

Many thanks!

Hesh Breakstone
Ann Arbor Guitars"

Hesh again: I have a saying that Dave is sick of hearing me say... I'd rather eventually get something right than to have always gotten it wrong....... So let's find out! No harm in asking, eh.

No biggy Hesh, decimal places are overrated anyway.
I think every repair person and builder knows the constraint required to not f#$%up a finish. I spent a full year of my life working to get those flawless Collings finishes out the door. What customers don't see or realize, is the real increase in cost they have paid to make/keep things looking flawless. When customers come in because their bridge is lifting they often seem perplexed. "why did this happen? "
If they knew at the time of purchase that this moment could possibly have been avoided or at least been put off in exchange for the risk of a small finish blemish I am sure many would have taken the deal in light of their new repair cost.

I find it ironic that the vintage Martin crowd, (an admittedly somewhat fanatic bunch), is busy pulling oversized bridges put on to conceal finish damage. They apparently decided that obvious finish damage is less important than the tonal implications of a historically correct bridge size. This even as makers are turning out instruments with what could be considered oversized bridges pre-installed.

well I think the whole guitar world expects flawless finish and of course the market had to respond to it...

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

David F. we had a Taylor owner recently who went on the nut about where his battery bag was installed indicating that it will change the tone of the guitar...... I'm not laughing because it was very real to him so much so that he was willing to go to great lengths to prove nothing beyond that he was an incredible PITA...

Compulsive obsessives seem to come in all flavors.... This from me who has been often called Felix Ungar many times in my life..... You should hear me clearing my throat right now, just like Felix used to do...

I didn't know that you used to work for Collings!!! I love their instruments and think that they are some of the best available these days.

A cut-away is yet another example of folks buying guitars with cut-aways but some, not all.... only do three chords, the cowboy chords..... Go figure. Willing to sacrife box internal volume for looks......

Anyway when I hear back I'll post a name-redacted reply. If by chance it does come to pass that Taylor has made a change it's interesting to speculate why they made the change. I've been noticing for a while that there seems to be some influence from the very high-end, individual Luthier made instruments toward the f*ctory instruments. There was a time when "R. Taylor", the plethora of Martin signature models, and the "custom shop" offerings of many makers now didn't exist.

Makes me wonder if collectively those of us who produced and sold custom made instruments got the attention of the big guys causing them to believe that they were leaving money and clients on the table with more limited model selections and options. Who knows but we do know that they have influenced us greatly so why would it be impossible for some of the good ideas that have originated with small makers to migrate to the big guys too.

Exactly! There is an old saying in the biz that goes like this: Whom ever decided that guitars should be shiny should be dug up and shot.....

Then dig up the guy who thought a satin finish was the solution and get him too.

A twofer.....

I'm not even sure when the trend started but perhaps it was from electric guitars? They are less affected by a thick finish than acoustic guitars so people thought if electric guitars could have a thick shiny finish why not acoustic?

I heard violin guys don't want a shiny violin, but I wonder if that's changing too?

_________________
Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I do it free hand but the key is just to take enough to get under the finish.
https://www.youtube.com/watch?v=P2-kXK_Nt38

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

UPDATE:

Taylor got back to me and as promised here is the scoop on Taylor rabbited bridges:

Taylor started using a bridge rabbit around the year 2000 and have been doing so every since on all models. We suspect that the reason that we had never seen one, yet, is that it's working for them and their bridges are staying put.

Previously IIRC Collings was the only manufacturer using the rabbit so it looks like the methodology is gaining greater industry acceptance.