We talked about the X-brace being a bit short, but other than that, I think it looks pretty good. Anyone else care to comment?
Is the small sound hole braces already glued in. I mentioned a couple of times that they need to be set back from the sound hole at least 1/4". But this is more about visual than structural. The brace will be very apparent when viewed from outside the guitar. If they are already glued in, might as well go with it.
Just to check, the bridge plate should extend at least 1/8" in front of the bridge and about 1/4" behind the bridge. Yours looks a bit narrow.
Replace old ply back with solid wood?
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Barry Daniels
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Re: Replace old ply back with solid wood?
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John Damon
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Re: Replace old ply back with solid wood?
I think it is a bit narrow, guitar has a big moustache bridge. But I got jumpy and glued it in before I saw this. It’s in, I hope it won’t be an issue, what could happen with a narrow plate? The top on this guitar is actually pretty thick. I’ll measure it later and see if you guys think it will fail. Thank you for all your help and tips, it is very appreciated!
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John Damon
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Re: Replace old ply back with solid wood?
The top is 1/8” thick
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Barry Daniels
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Re: Replace old ply back with solid wood?
That's definitely on the thick side so it may help with the short X-bracing. Still concerned about the narrow bridge plate though.
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John Damon
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Re: Replace old ply back with solid wood?
If I pieced in a bit in front and behind would that do anything? I know it would be joints, but I like that better than scraping out the plate.
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Barry Daniels
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Re: Replace old ply back with solid wood?
I don't think that would do much.
I don't know if the value of scraping it out and replacing would be worth the improvement in structure. Will leave that choice up to you.
I don't know if the value of scraping it out and replacing would be worth the improvement in structure. Will leave that choice up to you.
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Alan Carruth
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Re: Replace old ply back with solid wood?
Some old Martins with 'bar' bridges had plates that were exactly the same size as the bridge. The combination of the plate and the bridge ending along the same line made a huge stress riser: all the bending was at that point. I repaired a couple of 0-15s with mahogany tops that broke right at the front and back edges of the bridge. Not fun repairs.
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John Scime
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Re: Replace old ply back with solid wood? X brace conversion
A little late to the game, but thought I'd chime in regardless. First off - kudos to the OP for giving it a shot. This is not a simple task, and while the first result wasn't great, you did it! Loads of great comments from other posters that I'm sure was really useful - certainly was for me - as there is so much wisdom in this forum.
Many years ago I was inspired to work on X brace conversions by reading success stories on this forum. Since then, I've done a half-dozen x brace conversions and have been generally delighted with the results. And I always start with an actual plan or devise one myself based on photos from Martin or Gibson bracing. I see no reason at this point with my limited experience, to deviate from what has worked in the past. For this guitar - which looks similar to a harmony h162/h165 or or S621- I'd base my bracing a plan for Martin 000-18 with the 24.9" scale.
Rebracing a top with the sides attached is a pita because thebsides are ALWAYS in the way. Using my plan, I create a scale-sized pattern of the X using an old paper grocery bag or other thick paper, and cut it out. After first locating and outlining in pencil the upper transverse brace using on the OOO-18 plan, the X pattern allows me to position the X inside the attached sides, literally tape it in place in relation to the upper transverse brace and then lightly trace it in pencil. Then I measure to situate and draw in the finger braces, tone bars and bridge plate. When I'm done I have a drawing showing where everything goes.
Then I'll do a bunch of research on the forum and elsewhere to come up with brace width, height, carve pattern, etc. All of this is generally based on known successes.
I'm not an expert but this approach has worked for me. That and making sure you have SHARP chisels.
Many years ago I was inspired to work on X brace conversions by reading success stories on this forum. Since then, I've done a half-dozen x brace conversions and have been generally delighted with the results. And I always start with an actual plan or devise one myself based on photos from Martin or Gibson bracing. I see no reason at this point with my limited experience, to deviate from what has worked in the past. For this guitar - which looks similar to a harmony h162/h165 or or S621- I'd base my bracing a plan for Martin 000-18 with the 24.9" scale.
Rebracing a top with the sides attached is a pita because thebsides are ALWAYS in the way. Using my plan, I create a scale-sized pattern of the X using an old paper grocery bag or other thick paper, and cut it out. After first locating and outlining in pencil the upper transverse brace using on the OOO-18 plan, the X pattern allows me to position the X inside the attached sides, literally tape it in place in relation to the upper transverse brace and then lightly trace it in pencil. Then I measure to situate and draw in the finger braces, tone bars and bridge plate. When I'm done I have a drawing showing where everything goes.
Then I'll do a bunch of research on the forum and elsewhere to come up with brace width, height, carve pattern, etc. All of this is generally based on known successes.
I'm not an expert but this approach has worked for me. That and making sure you have SHARP chisels.
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John Scime
- Posts: 47
- Joined: Thu Mar 01, 2012 5:04 pm
- Location: Mississippi Mills, Ontario
Re: Replace old ply back with solid wood? X brace conversion
A little late to the game but thought I'd chime in regardless. First off - kudos to the OP for giving it a shot. This is not a simple task, and while the first result wasn't great, you did it! Loads of great comments from other posters that was really useful - there is so much wisdom in this forum.
Many years ago I was inspired to try an X brace conversion by reading a few success stories folks had shared on this forum. I've done a half-dozen now and have been delighted with the results - which I geel were because I always start with a bracing pattern from an actual plan drawing, or devise one myself from photos of old Martins or Gibsons. I see no reason with my limited experience, to deviate from what has worked in the past.
This guitar looks similar to a harmony h162/h165 or a silvertone S621-, so i'd base the bracing on Martin 000-18 with the 24.9" scale.
As anyone who has done it knows, rebracing a top when the sides are still attached is a pita because the sides are ALWAYS in the way. I can imagine trying it without the plan as a road map. From the drawing I make a scale-sized pattern of the X brace from an old paper grocery bag or other thick paper. Once cut out, I have a layout tool with correct brace location and angles, etc.. After first locating and drawing the upper transverse brace on the insidenof the top, my paper X pattern isnused to position the X - literally tape it in place in and lightly trace it in pencil. After that, its a lot easier to situate the finger braces, tone bars and bridge plate. When I'm done I have a drawing showing where everything goes, and the plans also provide detail with respect to bridge plate and brace thickness, etc.
Then I'll do a bunch of research to come up with brace width, height, carve pattern, etc. All of this is generally based on known successes.
I'm not an expert but this approach takes away the guess work and has resulted in guitars that sound pretty amazing. A little bit of reseach, some planning and layout, SHARP chisels or planes and good glueup technique goes a long way.
Many years ago I was inspired to try an X brace conversion by reading a few success stories folks had shared on this forum. I've done a half-dozen now and have been delighted with the results - which I geel were because I always start with a bracing pattern from an actual plan drawing, or devise one myself from photos of old Martins or Gibsons. I see no reason with my limited experience, to deviate from what has worked in the past.
This guitar looks similar to a harmony h162/h165 or a silvertone S621-, so i'd base the bracing on Martin 000-18 with the 24.9" scale.
As anyone who has done it knows, rebracing a top when the sides are still attached is a pita because the sides are ALWAYS in the way. I can imagine trying it without the plan as a road map. From the drawing I make a scale-sized pattern of the X brace from an old paper grocery bag or other thick paper. Once cut out, I have a layout tool with correct brace location and angles, etc.. After first locating and drawing the upper transverse brace on the insidenof the top, my paper X pattern isnused to position the X - literally tape it in place in and lightly trace it in pencil. After that, its a lot easier to situate the finger braces, tone bars and bridge plate. When I'm done I have a drawing showing where everything goes, and the plans also provide detail with respect to bridge plate and brace thickness, etc.
Then I'll do a bunch of research to come up with brace width, height, carve pattern, etc. All of this is generally based on known successes.
I'm not an expert but this approach takes away the guess work and has resulted in guitars that sound pretty amazing. A little bit of reseach, some planning and layout, SHARP chisels or planes and good glueup technique goes a long way.