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Acoustic Guitar Bridge Retrofit and Jig Creation
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=53302		 Page 1 of 1
Author:  PortlandGuitar [ Wed Jun 24, 2020 4:23 pm ]
Post subject:  Acoustic Guitar Bridge Retrofit and Jig Creation
A client sent us his seagull guitar to retrofit, he heard about our intonation improvements and wanted to try it on his instrument. Jay hadn’t performed this task before but being an engineer, he thought it a good task to take to help spread the bridges to the world. A jig was made to hold the guitar in plate while a new channel could be routed. A scary thing to do once you put someone’s favorite guitar in the surgeon’s chair. Fortunately, everything came out a success and the intonation was improved on this guitar. The improvements were measured before and after the bridge was put on so we got a good view of the changes the bridge and saddle can make.
Here is our photo journal of how we changed the acoustic guitar bridge.

Check out some analysis of the intonation quality before and after by visiting the full article here: Portland Guitar bridge compensation retrofit

Here is the seagull fresh onto the bench. The strings must be taken off.
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The saddle must be taken out. It appears there was a shim underneath to lift up the saddle in the bridge a little bit.
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First the saddle plates are made on the cnc
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Then the saddles are routed out.
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Here is one of the saddles put together
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The plan in making this acoustic guitar bridge retrofit jig is to make a plate which will hold a router so that a channel can be made in the right place. The top plate makes the shape needed available
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Here it is tested out on a piece of scrap wood. And it works.
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Here is what it will look like
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The mounts to hold the guitar are installed. The jig is complete, it’s ready to use.
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Foam is placed on the guitar to protect the surface of the guitar.
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Placed on the guitar. The side mounts are adjustable and squeeze the outside of the guitar providing a sturdy surface to route on.
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We’ve got to hold the guitar down, so elastic bands are used because they won’t scratch the finish.
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Clamp on
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The pegs are drilled out and filled in.
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The router in action
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Here it is after the first pass. It’s always a good idea to go slow.
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Complete
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The saddle plates fit like a charm
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The new pin holes are drilled
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It is complete
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Author:  Barry Daniels [ Wed Jun 24, 2020 5:45 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
It's a cool idea, but I am sorry to say that all those pieces will lead to buzzing problems down the road. It is inevitable. A fully compensated saddle is a better option. And this is coming from an engineer. My statement is supported by the various size gaps between the wood pieces in the closeup photo of the completed bridge.
Author:  Clay S. [ Thu Jun 25, 2020 5:54 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
"The saddle must be taken out. It appears there was a shim underneath to lift up the saddle in the bridge a little bit."

That wasn't an under saddle pickup? Have you tested out your creation with the various pick up systems that are often built in to guitars these days?
Author:  Bryan Bear [ Thu Jun 25, 2020 8:05 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
It sure looked like an under saddle pickup to me, there is an endpin jack too (but I don't see any controls in the side). I assumed it wasn't though or the OP would have had to clip the wires in order to remove it.
Author:  jfmckenna [ Thu Jun 25, 2020 8:42 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Barry Daniels wrote:
It's a cool idea, but I am sorry to say that all those pieces will lead to buzzing problems down the road. It is inevitable. A fully compensated saddle is a better option. And this is coming from an engineer. My statement is supported by the various size gaps between the wood pieces in the closeup photo of the completed bridge.

I wonder if a solid wood piece would solve that problem then. I don't see why the wooden container could not be one whole piece and then routed for indifidual adjustable saddles.

I agree though that a compensated 1/4in wide saddle is the way to go. I also wonder what individual saddles on individual containers does for tone.

But I still commend the OP for being innovative.
Author:  Freeman [ Thu Jun 25, 2020 10:27 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
As others have asked, how do you deal with the under saddle pickup (that is not "a shim"? I often find it difficult to balance strings with UST's - your system looks like a nightmare. And in your other post you used a compensated nut, why did you not install one here?

I'm also interested in how you are handling licensing of your design (I'm assuming you have a patent)
Author:  Barry Daniels [ Thu Jun 25, 2020 10:48 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Better machining tolerances would address some of my concerns. But not all. To me, this is a solution in search of a problem.
Author:  Clay S. [ Thu Jun 25, 2020 11:48 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Freeman wrote:
As others have asked, how do you deal with the under saddle pickup (that is not "a shim"? I often find it difficult to balance strings with UST's - your system looks like a nightmare. And in your other post you used a compensated nut, why did you not install one here?

I'm also interested in how you are handling licensing of your design (I'm assuming you have a patent)



I could be wrong, but the idea might not be worth the trouble to patent it. There is "prior art" that uses similar systems, including some with "fretlets" that move in a similar fashion. Rene LaCote and Daniel Frederich built guitars for "just intonation" where the fretlets could be moved in a similar fashion to change keys to keep pure intonation.

https://www.youtube.com/watch?v=AQgybkGPETU

However, If Max can perfect his system he may have a head start over the competition and be able to snare enough of what market share there is without the expense and hassle of acquiring and defending patents.
Equal tempered tuning has become so widely accepted among quite a number of instruments that playing in just intonation makes you play "out of tune" with everybody else. The old wooden flutes were often set up for particular keys, and you had to have a different flute to play in a different key. Modern flutes use ETT even though it makes them sound bad.
Author:  Bryan Bear [ Thu Jun 25, 2020 12:02 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
This isn't providing just intonation though is it. This is merely allowing for adjustable compensation to improve overall intonation. Or do I have that wrong. All of the compromises that fretted instruments make still exist but this provides a different way to get close. I don't think it provides end results that are any different than we achieve when we compensate each string by filing the break point on a typical bone saddle. The difference being that a change in string gauge can be adjusted for compensation by moving the saddles instead of filing or replacing the traditional saddle.
Author:  Clay S. [ Thu Jun 25, 2020 12:21 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Yes, that's true Bryan,
It is a bit of a "half step", however the mechanics and intention are very close to what has already been done. And if you consider the electric guitar world, you might see some similarities with Ted McCarty's TOM. Which is not to be negative or dismissive of the idea, but rather that it is an improvement that not everyone will feel they need, and similar to Novak's fan fart, may not be worth the effort to patent.
Author:  Bryan Bear [ Thu Jun 25, 2020 2:38 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Clay S. wrote:
Yes, that's true Bryan,
It is a bit of a "half step", however the mechanics and intention are very close to what has already been done. And if you consider the electric guitar world, you might see some similarities with Ted McCarty's TOM. Which is not to be negative or dismissive of the idea, but rather that it is an improvement that not everyone will feel they need, and similar to Novak's fan fart, may not be worth the effort to patent.


Clay, I think I sounded more like I was disagreeing with you than I intended to, you have summed it up well with the above quote.
Author:  meddlingfool [ Thu Jun 25, 2020 5:23 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
I just want to know about the pickup.
Author:  PortlandGuitar [ Sat Jun 27, 2020 9:35 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Sorry about the long delay.

We've used this with under saddle pickups before. We route a channel in underneath the plates then the pickup fits in there. A plate is put over it to squish it into position. Then the saddle plates sit over it. We've had success using this design and the pickup came out with even gain on every string.

We haven't had problems with buzzing, and the plates make a tight fit. A one piece insert might reduce this problem by reducing the possibility for slack.

We sell our bridges, so anyone can put this on a guitar. Licensing is something we're willing to do.

I should introduce myself a little better. My name is Max and I'm the son of the luthier who did this, Jay. He's been doing this for 15 years and is a mechanical engineer. Most of what I post is sharing his ideas and work.
Author:  meddlingfool [ Sat Jun 27, 2020 1:06 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
What happened to the pickup that was in that guitar?
Author:  PortlandGuitar [ Sat Jun 27, 2020 5:34 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
I don't remember there being a pickup in it when the retrofit happened.
Author:  meddlingfool [ Sat Jun 27, 2020 6:09 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
That silver strip in the second photo that you posted was a pickup, not a shim to raise the action.
Author:  SteveSmith [ Sat Jun 27, 2020 6:11 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
meddlingfool wrote:
That silver strip in the second photo that you posted was a pickup, not a shim to raise the action.


Yup.
Author:  J De Rocher [ Sat Jun 27, 2020 11:39 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
I like the basic idea of the design, but I'm not convinced it's needed in practice for the majority of guitars, guitar players, or guitar builders. I have had a fair number of acoustic guitars over many years and never had intonation problems come up with changes in humidity. How many guitar players make changes in the gauges of their string sets that are big enough that they have a significant effect on intonation? I've never had any problem accurately locating a bridge with a standard one-piece saddle on the top so that it can be intonated properly.


Instead of six separate wood base plates, couldn't you have a single wood base plate? That way the total number of pieces would be reduced from 12 to 7 and if you needed to lower the action, you could reduce the height of the single base plate in one go instead of having to adjust the heights of 6 bases individually (while preserving the radius). If you needed to raise the action, you could just crank out another thicker single base plate on the CNC. A one-piece base would also look nicer, IMO. The uneven gaps between the 6 base pieces in the second-to-last photo above would be unacceptable to me.

In combination with a one-piece base plate, could you use the CNC to first radius the full-length saddle blank, ramp the sides of the top edge of the full-length radiused saddle, and then use the CNC to rout out the individual saddle blocks? That would give you 6 saddles with the correct radius built in. You would need to keep them in order, but that wouldn't be hard. Combine that with a one-piece wood base plate and you could adjust the action easier and faster and do so without having to worry about mucking up the overall saddle radius.

Since I haven't tried to make a bridge/saddle like this though, I may well be missing something that would make those two changes a bad idea.
Author:  J De Rocher [ Sat Jun 27, 2020 11:43 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
meddlingfool wrote:
What happened to the pickup that was in that guitar?


When I look closely at the second to last photo above, I see something through the three center gaps between the base blocks that looks like it could be the pickup.
Author:  meddlingfool [ Sun Jun 28, 2020 12:53 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Good eye! Methinks you might be right!
Author:  PortlandGuitar [ Sun Jun 28, 2020 8:27 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
I apologize, that does look like a pickup. My dad did the retrofit, so I wasn't clear on everything. I post for my dad who has been a luthier for awhile. We work under the name Portland Guitar.

I agree that the problem isn't major, not everyone will hear it and it won't cause most people any trouble. For the people that do hear it and want the guitar to sound different it could be practical.

I will share those ideas with my dad. I like the idea of a one piece insert, I think that would look a little better. The second idea is possible in the cnc though. We do something similar to make the saddles right now.
Author:  Clay S. [ Sun Jun 28, 2020 9:50 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
When you look at the historical record of guitar "improvements" most have not stood the test of time, whether it was because they didn't work as advertised, were too difficult or expensive to manufacture, or people didn't feel they made a significant improvement. Many of the features I have incorporated in my travel guitars were introduced by instruments that are over a hundred years old. Tilt-able and de-mountable necks, pinless bridges, and ports of various designs are old news. They add complexity to the construction which in most cases isn't needed, which is why they have been abandoned for the most part.
But if you look images of recent bridge designs you will find quite a number exploring various shapes and materials, and concepts different from what is traditional. They all have their proponents and detractors, and eventually will have to stand on their own merit.
Over the past couple of decades that I have been building travel guitars my bridge design has evolved. I am on the third iteration, and if I see a way I think will further improve it, I will have a forth.
This forum is about sharing ideas, and although at times we seem critical, it is generally with the best of intentions. There is always room for something different in the guitar world, and exploring designs old and new is part of the fun.
Author:  J De Rocher [ Sun Jun 28, 2020 4:32 pm ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
PortlandGuitar wrote:
I apologize, that does look like a pickup. My dad did the retrofit, so I wasn't clear on everything. I post for my dad who has been a luthier for awhile. We work under the name Portland Guitar.

I agree that the problem isn't major, not everyone will hear it and it won't cause most people any trouble. For the people that do hear it and want the guitar to sound different it could be practical.

I will share those ideas with my dad. I like the idea of a one piece insert, I think that would look a little better. The second idea is possible in the cnc though. We do something similar to make the saddles right now.


I was thinking some more about the bridge design and I think that instead of my second idea above about radiusing the full-length saddle blank and then cutting out the individual saddles, it seems that the radius could be incorporated directly into a one-piece wood base plate. You could radius the top surface of the base plate with the fretboard radius and then use the CNC to cut the six slots for the separate saddles to a constant depth below the radiused surface of the base plate which would transfer the radius to the slot bottoms. That would allow you to continue making individual saddles that are identical to each other and are interchangeable the way you show in the photos above and allow simple action adjustment to a one-piece base without affecting the radius.

Anyway, it's good to see people trying alternative ideas and I agree with Clay's comment above: "There is always room for something different in the guitar world, and exploring designs old and new is part of the fun."
Author:  Tai Fu [ Tue Jul 07, 2020 10:01 am ]
Post subject:  Re: Acoustic Guitar Bridge Retrofit and Jig Creation
Forget UST. Your design will not allow under saddle pickups at all. Only thing that will work is piezo or microphone, or soundhole.

Some guitars have those weird integrated saddles and it will only work with the saddles that guitar came with.

A German luthier I have known back in the day have a system where instead of a slot the saddle goes into, there's an incline where the saddle goes. The saddle sits on the incline (it is 2 piece) and can be moved to improve intonation. The string holds the saddle on similar to a banjo. Again that system will not allow undersaddle pickups. They also have their pros and cons.

Furthermore the design requires significant modification to the guitar. I don't know if that will compromise things. You're talking about a piece of wood less than 1/8" thick that must hold up about 100 pounds of string tension. There's a reason for the traditional designs.
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