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I use Ken's method of putting a slight bevel around the perimeter of the bottom of the bridge and then angling the blade as I scribe the footprint. If the goal is a rabbit of .010 or less, I suspect the practical results will be indistinguishable -- at least in my shop.

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George :-)

I should have taken that left turn at Albuquerque....

Thanks for this discussion. I've been putting the rabbet on lately. Maybe a little too much of one.

Good stuff.


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You are not alone, 10 thou wide makes mine pucker too....

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Gary asked how and I hijacked with why so here's a follow through.

Using a piece of scrap to test the rabett size. I leave my router set for a larger and deeper ledge and adjust a few thousandths smaller with tape layers on the bearing or base plate. It's a lot easier than trying to move the router or guide in tiny increments.
This ledge is .025" wide.
Neck crack fixed, brace ends glued, bridge on tight, on to the back crack......................

Awesome! But what is your technique for acheiving the perfect pocket?

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My memory is so good, sometimes I remember things that never happened.

Beautiful craftsmanship there Dave!!!

Nice post David. A couple of lessons I have learned doing a narrow ledge is that the right angle corners of the wings are a common place where residual finish may prevent seating and that the depth of finish may not be consistent over the whole footprint.

I do a test rout on a small piece of scrap and make sure it clears the finish in every location on the bridge footprint.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

OK, on the two guitars I am working on right now, I am going to switch from my prior "full footprint" method of gluing on a bridge to the ledge method. I take to heart the advice of the repair folks that this is the best of all worlds.

I have a question about my preliminary plan. Can those who are really good at this let me know if you see problems with this? It will likely vary a bit from what some of you do, but difference does not automatically mean it's wrong. Just different.

I plan to finish the whole top. No masking.

I plan to contour the underside of the bridge to perfectly match the top. If anything, I might hollow out the middle just a smidge, so that the wings are not tempted to flip up at the corners when I later clamp.

I plan to put down a 2" wide, 8" or so piece of Frisket Film where the bridge will sit, figure out the perfect bridge location, then lightly clamp it to make sure it does not move during marking. I will make multiple checks after clamping to make sure clamping did not mess up placement.

I plan to use a 0.5 mm mechanical pencil to mark the outside edge of the bridge onto the Frisket Film. This will be meticulously done, making sure that the pencil line is of uniform thickness all the way around, and making triple sure that the mark is flush to the edges of the bridge all the way around. Good, dark lines, the full thickness of the 0.5 mm lead all the way around.

I plan to remove the bridge. Then I plan to freehand draw another line with the 0.5 mm mechanical pencil onto the Frisket Film, but this line will be on the inside edge of the other line I just drew. Again, I will be really careful (using an Optivisor) to keep the line of uniform thickness, 0.5 mm all the way around, making it good and dark, and easy to see in contrast to the Frisket Film. This should give me an inside border that is 0.5 mm inside the outline of the actual bridge, which is 0.02" wide.

I then plan to lightly score inside that second line with a decent, sharp marking knife (not an X-Acto), making sure to be flush, but not over, the inside line. The goal will be to just cut through the finish, nothing more. Then I will remove the inside bit of Frisket film, but leave the outside bit of Frisket Film on the guitar.

I then plan to either scrape or rout off the finish inside that scored line I just made. I think I will rout it, but I have not fully decided. Either way, I will make absolutely sure there are no severed fibers left inside the pocket.

I then plan to measure the depth of the pocket I just made, if I made it by hand, factoring in the thickness of the Frisket Film. I will know the depth if I routed it. If I made it by hand, tweaking the depth to get it uniform may be in order.

I plan to use my mini-router setup (I use a laminate trimmer with a collet reducer for 1/8" shank bits, rather than a Dremel) to put a ledge on the underside of the bridge. The vertical depth of the ledge will be determined by the measurement of the pocket I made, plus a minute amount. The horizontal depth of the ledge will be just a smidge more than the 0.02" I left inside the outline of the bridge when I made the hole. Maybe 0.025". I figure test cuts on scrap binding shorts will allow me to sneak up on the perfect depths in both axes.

I plan to remove the rest of the Frisket Film, then test the bridge for whether it fits into the pocket. From there, I will move on to gluing with HHG.

Does this sound right? I figure that a 0.5 mm mechanical pencil mark, if I am careful, is about as thin a ledge as I can realistically manage. I am planning on using smallish pyramid bridges on these guitars, so I want to maximize the gluing footprint, but the idea of keeping the finish tucked in just a bit, to minimize future repair costs, makes a lot of sense, too.

Sorry for the long post, but the marking part of this job leaves me with questions about the right way to go. Thanks for feedback.

Don it all sounds fine to me and my hats off to you for being such a planner.

The only thing that I would suggest is that the difference between a very, very small ledge/rabbit and one that is easier for us to see and work with is mouse nuts in terms of wood-to-wood contact area. In fact I'm a believer that the .010" ledge that Dave Collins does is great for Dave but I would not recommend it for everyone. It's better in my view to give up a very small fraction of a percent of wood-to-wood area to insure that the pocket is sufficient that there in no chance of gluing the thing on slightly out of the pocket.

Just to give you a view of what we do since we do this several times a week for years now with this method you won't see the planning that you've done in our shop.

We trace the actual bridge with a hobby knife one side or end at a time ever so slightly moving the bridge just inset of the visible finish line. Holding the bridge in place and scribing a few strokes as you indicated only though finish.

The finish is removed with a very sharp chisel and the fit is also refined until the bridge rabbit "snaps" into it's pocket and you can feel this.

Obviously there are lots of ways to get the same result this is just how our busy shop glues bridge on.

Your method sounds great I am simply a little concerned that we, including me have made this sound more complicated than it is. Only several million bridges have been glued on with little care and not much finish cleared and many of them do make though time.

One more observation. I would nix the rabbit for a French polished top. If film thickness is something like .0015" which is what my FP tops were no ledge is necessary and instead I would simply clear finish to very near the bridge perimeter but not to it.

Good on you for trying this too!

I do, in fact, French polish, so I'm glad I asked! Yeah, for a really thin finish, I can see the natural flexibility of the wood (combined with decent clamping pressure) making it so that the ledge is not absolutely necessary. But I didn't want to assume that was true. You and other repair folks are the ones who see when things go wrong, and I put a lot of value on that perspective.

Which brings up a related, but broader, comment: I pour over comments from you and other repair-focused folks in order to figure out the best decisions to make while building. As you and I have discussed before, I want to build guitars that outlive me and my grandchildren, so the ability to be repaired is high on my list of priorities for what I build. If you ever decide to put down, in writing, all of your "please build this way, but not that way, to make future repairs easier" wisdom in one tome, I will buy it. I suspect others would too. Thanks, as always.

I've always finished the guitar with a piece of masking tape to cover the foot print of the bridge about 1/8th in smaller and then follow that up by scribing a line to remove the finish and fill the complete foot print. But I'm pretty confused about this thread. I can see that this is a good idea for cosmetic reasons, it is hard to get a perfect foot print but not impossible. And even in the case of error you can fix it though admittedly that sucks.

But in thinking about it, I don't see how this is an issue for future repairs and in fact might work against it. I drew a very simple line diagram to outline my thoughts on it. The spatula, straight line to the right, now has to reach under the rabbet to get to the wood/wood contact and seems to be in the way which would crush the finish anyway.

I think the idea is that, if you are taking off the bridge, it is because the bridge is already lifting up somewhere, and needs to be removed, then re-glued. If it is already lifting up somewhere, then that provides ample space for the spatula to get underneath the bridge, even with the existence of the ledge. See what I mean? Unless you are removing a bridge for some other reason (a big crack along a grain line, for instance), getting underneath it is not going to be an issue.

I have always masked the top with low tack tape. The bridge has been located and fixed with two 1.4mm brads in the saddle. I score around the bridge with a #11 blade angling in a little. Remove the bridge and tape that covers the footprint and rescribe 1/32" inside the tape margin. Remove with the router technique close to the line and finish with a chisel and small sanding blocks.

Then remove the tape and do test ledge routs to make sure they clear the finish.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Perhaps read some of the prior posts here specifically my reply to Dave F. over his similar concerns. All your concerns have been addressed with real life, actual experience removing rabbited bridges and it's not more difficult. In fact regarding comparing a rabbited bridge to a full bridge perimeter clearing the full perimeter clearing is FAR more dangerous to the surrounding finish and far less serviceable in the future sense because of the damage to the finish.

Or in other words with the rabbited bridge the crushed finish from the pallet knife is under the bridge and out of site. With full perimeter clearing the finish gets damaged the next time the bridge lifts in plain view. Do this on a sunburst and you just ruined the instrument.....

Lastly clearing the finish from the full perimeter OR rabbiting is no guarantee that the bridge will not lift again since abuse and lots of things can make this happen. As such we always try to either maintain serviceability going forward of improve it if possible.

Rabbiting bridges permits us to improve the glue joint by expanding it over the f*ctory job or Luthier job AND improve serviceability over a full clearing of finish because where the pallet knives will go is not visible.

One last thing. I am speaking of a rabbit with a depth around 1/3 or less the thickness of a pallet knife, it glides right over it, I've done it many times when we used to use Fish glue in a climate too humid for it.

EDIT: In your drawing make your pallet knife thickness 3 - 4 times the depth of the pictured pocket and rabbit and you will clearly see what I mean.

I almost always, in fact probably always, come from all sides of the bridge especially in the cases with pretty severe runout.

Oh no! you guys! we're' back where we started!

Don, You are meticulous! It's easier than that.
As a point of departure, go to Ann Arbor guitars web site and watch Dave do it at light speed in the "gibson plastic bridge replacement" video. Mark x, y, bridge location with tape, jog back from the tape and use the bridge it's self as a guide for the knife. Free hand would be tough! Dave holds the bridge with one hand because he has serious huevos. I clamp it. Front and back edges separately and hold back on the ends. leave the tape on so you can always see where you are. Make sure all your lines connect at the corners.

Words just flat out suck for stuff like this. I have things to show and tell I just don't have time at the moment.

We all do but after reading runout and marking it on a piece of tape we come in from the lift first to test the gumminess of the glue before going at it in earnest. It can take a while, several minutes minimum with our heat lamp to heat through the bridge enough to let the glue start to give. That lifted corner is a great test spot or the back edge, where ever the lift is.

If the glue is hot enough there is far less chance of runout being a major issue. We still pay attention, stop when we feel fibers but it's easier in my experience to let heat, time and experience remove a bridge.

Ok I'll probably give it a go on my next guitar. I aint makin' any promises that I will change tho

I'm the same way, if something works for me there is something to be said for consistency and certainty.

To be a Devil's advocate how we do it does box us in at times in terms of the overhead to do a bridge reglue. If we want to do something quickly and cheaply such as for a repurposed guitar that we are giving away to someone the factory way, after clearing more finish of course because that's easy, may be good enough.

I'll take the risk and be completely honest here for all to see. We often describe the best way forward that we can think of. This often means jigs, 20/20 vision, HHG and knowledge of same, knowing your platen, the touch and experience.

But OTOH most guitars ever built, likely 99% of them were not built with these methods and many of them do fine for a lifetime.

Am I advocating shoddy work? Not at all but I am also being realistic knowing in advance that if we scare away the next generation of Luthiers because we approach this at ALL times with surgical precision who are we really serving and perhaps are we even motivated at times by being competitive.......

It's all relative and sometimes what gets the job done and is more than good enough is pretty OK too.

In my view I share this stuff because it was a huge discovery to me when I got turned on to it but I personally do not always agree that methods such as this one are "appropriate for the instrument." If for example the kid who can't afford what we charge to reglue a bridge because we approach it like NASA our approach is actually a detriment to the industry if the kid quits playing and takes up the stinkin iPad....

Lastly I believe that to appreciate what we might advocate it's helpful to try other methods and actually experience some of the things that can go south on you so that one can appreciate why we do what we do and what it gets you.

We take fretting at our shop to a level not seen elsewhere in my experience. We've had a standing challenge into anyone with a PLEK but have not had any takers in five years now. We honestly believe that our methods provide superior results to a PLEK. The one PLEK shop that we got to agree to the challenge would not agree to let us publicize the results for better or worse. That was the entire point.

With fretting stuff can matter when a pro player wants action not possible with anything less than a VERY dialed in PLEK run with the full program (manufactures often run shortened programs for production sake) by a skilled operator or from a Luthier using manual methods taken to the degree of a master machinist.

With gluing on a bridge does it matter how any of us do it if it's on there, stays on there and remains serviceable?

With this said I'm becoming increasing aware that scaring the hell out of people with taking this stuff too far may be a disservice to all. Hope that's not what I'm actually doing because that is the last thing I ever want to do.

There is a long, and growing, list of things that scare me in this world, but learning more about how to do A plus repair work, and how that can feed into better building, is not on that list. I can't speak for everyone, but as far as I'm concerned, please don't stop describing how you guys do A plus work. I can figure out how to do a hack job on my own.

Noted and thanks for this Don. Nice to know that there is an audience here for doing the details and top shelf work!

I'm with Don. We can't be the only ones. :-)

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George :-)

You're not

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Steve Smith
"Music is what feelings sound like"

For sure.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I greatly appreciate this gentlemen and ladies because at times it is a bit like beating my head against an Ov*tion trying to get folks to see why serviceability is important!

Don my approach to building was just like yours, I saw no reason why what we craft should not last 100 years and beyond.

On another forum one of my mentors, Rick Turner is reiterating what I took offense to 12 years ago and he was spot on and I was a snowflake.... Learn repair BEFORE you learn to build and you will be a far better builder. Sorry if I offended anyone... but Rick's right and even learning repair as you learn to build will make you a far better builder. AKA..... you can get more $$$ for your stuff too...