Tucked braces & bridge plate joints - not kerfing

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Morecowbell
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Tucked braces & bridge plate joints - not kerfing

Post by Morecowbell »

As I’m doing research on my Dreadnought build I came across a thread on the Unofficial Martin Forum that discussed tucked braces/bridge plates. This was not referring to tucking into the kerfing but about the mating joints between the tone/finger bars/bridge plate and the X-brace.

This joint is shown on the StewMac plan as 45 degree angle on the end of the brace going into a corresponding 45 degree pocket on the X-brace. The forum discussion asserted that when Martin did these in the early days they were a blind mortise and tenon joint, 1/3 to ½ of the width of the X-brace deep.

I know that butt joints are generally recommended for these now, and that's what I did on my OM, but I’m curious about what Martin did originally and may try it on my Dread.

So my question is, does anyone know from experience how Martin did this? And when they did it and when they stopped doing it? I was wondering if John has come across this in all his Martin repair experience.

Thanks
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
tippie53
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Re: Tucked braces & bridge plate joints - not kerfing

Post by tippie53 »

braces were tucked and I am not sure of the cut off on the pre wars I saw all the braces were notched into the X. I suspect this was a tradition.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Morecowbell
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Re: Tucked braces & bridge plate joints - not kerfing

Post by Morecowbell »

Thanks John!
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
Bob Gleason
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Re: Tucked braces & bridge plate joints - not kerfing

Post by Bob Gleason »

I learned to tuck braces by using a good sharp chisel, slightly wider than the brace to be tucked. Just push the chisel into the glued brace at the joint between the top or back and the brace, being careful not to push so hard as to pry off the glued brace.You'll get a nice, wedge shaped pocket that you can tuck the brace into. Obviously you have to taper down the end of the brace going into the pocket. Easy and works good for me.-Bob
Morecowbell
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Re: Tucked braces & bridge plate joints - not kerfing

Post by Morecowbell »

Thanks Bob - that's the type of joint that the StewMac plan shows, which I've thought was odd until reading your explanation of how to make it, and now it makes more sense all the way around. Very interesting.
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
tippie53
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Re: Tucked braces & bridge plate joints - not kerfing

Post by tippie53 »

as one that got to see a lot of these old guitars , I have found that I can see when a different hand worked on them. Its in the carving , and in the notching. I had the opportunity to talk to a man named Marcellus Trach that worked at the factory during this time.
The process as he explained it was , First the bridge plate was glued. Then then tone bars and finger braces. These all had that end that went under the brace. Some were done with that angle on the face end. Then the X braces were put on top. One thing I noticed was often there was about an 1/8 in opening or gap behind the plate. That was there so if the plate ever needed to be pulled you could do that without opening the X braces.
When you think about all the skills that were used to make the old guitars , it was amazing the skills. I have seen ice cream cone heels apart and the accuracy was amazing . This was all done by hand.
I have have seen some early guitars where the notch of the braces into the x were almost paper thin and were under the x , and the X was notched to fit over that.
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com
Morecowbell
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Location: Fishers, IN

Re: Tucked braces & bridge plate joints - not kerfing

Post by Morecowbell »

Hi John,

That's the technique that was described on the UMGF. There are some great pics on vintagemartin.com of top bracing where you can see the pencil lines that mark the locations for the mortises on the X-braces of early guitars - the idea being that if the bridge plate, tone bars and finger braces were glued first, you'd have to mark the X-braces for the notch locations. A lot of extra work and as you say, a lot of skill required - easy to see why it faded away.

Many thanks
"Facts seldom sway an opinion." - John Hall
"The difference between theory and practice is that in theory there is no difference." - Van de Snepscheut
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