Number 16

[kiwigeo]

With the multiscale OM gone work has resumed on other builds in my shop. Number 16 is a Gore style OM..pretty much as per the multiscale but conventionally scaled. Over the weekend I got the back made up and glued in.

[demonx]

Looks great, I wish my "cut ins" were that tidy!

[kiwigeo]

Looks great, I wish my "cut ins" were that tidy!

I changed my method for this. Rather than stuff around with chisels to cut the pockets, after doing the initial cuts with the razor saw I went in with a Dremel and a Stewmac router base and hogged out the pockets with same. The router depth was set against each brace end. Pockets were then tidied up with a small file to get a nice tight fit. For many this sort of thing isn't important but for anal people like me it's important that if anything is visible from the sound hole it has to be presentable!

[johnparchem]

Looks great. It looks like you are well on your way with this guitar.

[Allen]

Well if you want to get anal about braces, can I make a sugggestion going forward Martin. The way you are doing the braces through the sides like that has a very high probablility of causing structural issues down the track.

With the ends of the braces going to end up being in contact with the bindings once they are installed, they will pop bindings loose if the top or back plate shrinks due to low humidity. There are several luthiers posting pictures of guitars and ukes on some private pro builder forums I'm on that this has happened to. And the repair guys tell the builders that it keeps them busy doing all those repairs.

You can still cut through the sides if that makes routing out the area easier. Just make sure to mark your brace lenght and cut it shorter than where it may contact the binding material. I have been doing mine 1-2mm short for years now after I saw a repair article by Linda Manzer.

[demonx]

Well if you want to get anal about braces, ....

The way I was shown was to cut into the lining with the chisel, however not through the side. I think this is what you are suggesting.

The trouble I have is when I try to cut into the lining it just breaks away and looks messy. The dremel looks like a neat and simple solution, would probably take half hour longer but could save half an hour trying to neaten up a messy chisel job!

[kiwigeo]

Well if you want to get anal about braces, can I make a sugggestion going forward Martin. The way you are doing the braces through the sides like that has a very high probablility of causing structural issues down the track.

With the ends of the braces going to end up being in contact with the bindings once they are installed, they will pop bindings loose if the top or back plate shrinks due to low humidity. There are several luthiers posting pictures of guitars and ukes on some private pro builder forums I'm on that this has happened to. And the repair guys tell the builders that it keeps them busy doing all those repairs.

You can still cut through the sides if that makes routing out the area easier. Just make sure to mark your brace lenght and cut it shorter than where it may contact the binding material. I have been doing mine 1-2mm short for years now after I saw a repair article by Linda Manzer.

You make some valid comments there Allen and I'll take them on board. With the exception of the UTB my top braces stop short of the sides.

[Allen]

I'm looking at the back transverse brace ends poking out the sides and are flush trimmed. Those are the ones I can see and thought I'd mention.

[kiwigeo]

I'm looking at the back transverse brace ends poking out the sides and are flush trimmed. Those are the ones I can see and thought I'd mention.

The way I see it the best thing to do would be to cut my pockets as I have been doing. Test fit the back and fit the glued on guide tabs on the overhang to line the back up with the sides (I currently do this) and then trim braces so they are just short of the inner limit of the binding channel. To prevent glue filling the gap I'm thinking to insert some pieces of teflon which I can pull out when I route the binding channels.

[blackalex1952]

Lovely neat workmanship!
I use the dremel method, but I have a paddle which sits on the sides of the guitar like a sanding paddle would. One end has a perspex section which is slotted for the dremel and the job can be seen through the perspex. That way the router base sits on something solid rather than balancing on the liners. I set the brace end heights with the little sanding blocks in the attached photo, then set the router depth of cut on the brace after it has been sanded. -Ross

[kiwigeo]

Lovely neat workmanship!
I use the dremel method, but I have a paddle which sits on the sides of the guitar like a sanding paddle would. One end has a perspex section which is slotted for the dremel and the job can be seen through the perspex. That way the router base sits on something solid rather than balancing on the liners. I set the brace end heights with the little sanding blocks in the attached photo, then set the router depth of cut on the brace after it has been sanded. -Ross

Nice trick with those little sanding blocks.....I use a cruder version of your dinky little aids...I have a 2mm piece of MDF that sits around the end of the brace and I use that to sand all brace ends to 2mm.

[simso]

With the ends of the braces going to end up being in contact with the bindings once they are installed, they will pop bindings loose if the top or back plate shrinks due to low humidity. There are several luthiers posting pictures of guitars and ukes on some private pro builder forums I'm on that this has happened to

That is a very interesting point, I actually do mine as pictured above as well, something for me to ponder on, I may be altering my process.

Steve

[kiwigeo]

Thanks to Allen I've been obsessing all day about brace ends and pockets!!

On the current build I'm going to rout the binding channels and then chisel back the brace ends by 1-2mm before installing bindings...this will allow for any future back movement.

[blackalex1952]

I have a 2mm piece of MDF that sits around the end of the brace and I use that to sand all brace ends to 2mm.

I use the 2mm++ brace end height guide as well, with a chisel or a scraper, but fine tune with the sanding blocks.-Ross

[Trevor Gore]

With the ends of the braces going to end up being in contact with the bindings once they are installed, they will pop bindings loose if the top or back plate shrinks due to low humidity.

Thanks to Allen I've been obsessing all day about brace ends and pockets!!

Relax, Martin!

For the brace ends to poke the bindings off, one of two situations has to occur:

1) The back (say) shrinks, stays attached to the linings but detaches from the braces. The back pulls the sides in and pokes the brace through the bindings. If the back and brace remain attached to each other, the brace moves with the back and nothing happens to the bindings. So the problem here is the brace detachment rather than how the brace is socketed into the linings.

2) The perimeter (i.e. the sides) shrink in length and shorten, pulling themselves inward. The glue line between the lining and back (say) fails and the brace ends poke the linings off. If the sides aren't brought back to equilibrium at 45% RH before boxing up, this could happen, but it requires the glue line between the back and the sides to fail. I've glued end blocks in too soon before now and watched sides pull away from the mould a few days later as the sides have dried out. The solution is to let the sides dry out before doing more work on them.

So, to me, brace ends poking the linings off is a symptom of something else done wrong (like improper humidity control), not the way the they're fitted in the linings. BTW, I've never seen this in real life, but I once saw a pic somewhere positing the socketing method as a cause.

[kiwigeo]

Thanks for the comments Trevor.

[Dave M]

Martin I notice that it is again a cutaway. Do you think you've now cracked the technique (as it were)? Though I think that like my last and current build you are using a slightly less extreme curve for the 'nose'...?

I have persuaded my version of a side bender to reasonably reliably produce a cutaway bend, though I'm still not getting a great fit to the mould shape.

Ross yes of course providing a platform for the small router is the way to go. I shall make something up at once. Thanks.
We do tend to lose sight of basic principles when faced with a slightly unusual machining job.

[routout]

Nice work 16 jeeps that's a good number ,thank's for the pics.

[Trevor Gore]

Thanks for the comments Trevor.

No worriers, Martin. It would have been better if it made more sense ! There are a couple of places where I typed "linings" instead of "bindings", corrected in the piece below:

With the ends of the braces going to end up being in contact with the bindings once they are installed, they will pop bindings loose if the top or back plate shrinks due to low humidity.

Thanks to Allen I've been obsessing all day about brace ends and pockets!!

Relax, Martin!

For the brace ends to poke the bindings off, one of two situations has to occur:

1) The back (say) shrinks, stays attached to the linings but detaches from the braces. The back pulls the sides in and pokes the brace through the bindings. If the back and brace remain attached to each other, the brace moves with the back and nothing happens to the bindings. So the problem here is the brace detachment rather than how the brace is socketed into the linings.

2) The perimeter (i.e. the sides) shrink in length and shorten, pulling themselves inward. The glue line between the lining and back (say) fails and the brace ends poke the bindings off. If the sides aren't brought back to equilibrium at 45% RH before boxing up, this could happen, but it requires the glue line between the back and the sides to fail. I've glued end blocks in too soon before now and watched sides pull away from the mould a few days later as the sides have dried out. The solution is to let the sides dry out before doing more work on them.

So, to me, brace ends poking the bindings off is a symptom of something else done wrong (like improper humidity control), not the way the they're fitted in the linings. BTW, I've never seen this in real life, but I once saw a pic somewhere positing the socketing method as a cause.

[kiwigeo]

Martin I notice that it is again a cutaway. Do you think you've now cracked the technique (as it were)? Though I think that like my last and current build you are using a slightly less extreme curve for the 'nose'...?

I have persuaded my version of a side bender to reasonably reliably produce a cutaway bend, though I'm still not getting a great fit to the mould shape.

Hi Dave, I cracked the bending of the cutaway on this guitar.....3 sides trashed in the process. I learned in the process though and on the current build the bending of the cutaway went alot smoother. One thing I did do was rejig the radius of the cutaway horn to a slightly less tighter radius. I have a side bender but it hasn't had much use of late....I prefer to my side bending by hand.

[blackalex1952]

Have you tried boiling the sides in water prior to bending? I have not done this but am going to give it a try. It was suggested to me by a luthier friend.-Ross

[kiwigeo]

Have you tried boiling the sides in water prior to bending? I have not done this but am going to give it a try. It was suggested to me by a luthier friend.-Ross

I tried this on an early build but found that with Indian Rosewood it wasn't really necessary. For tight bends I go as thin as possible with the side, I use water with fabric softener and just alot of patience. I'm also careful about supporting the wood on the outside of the bend....one advantage of bending by hand is that you usually get early warning that wood is going to pop out and you can adjust accordingly.

[Dave M]

Hi Martin

I ended up with this shape. (a falcate braced classical) As much due to poor bending as a design choice. It will probably play OK. The cutaway will be good enough to allow the player to get at the upper frets, but it really wasn't what I was aiming for aesthetically.
I really like TG's cutaway shape and although I don't have to see the 'nose' quite as sharp as Trevor manages I would like it tighter than on this build.
I made up the bindings with Mahogany to match the rosette with a BWBW purfling and couldn't for the life of me bend them on the iron. Finally dug out the side bender and managed to get them into shape. It certainly seemed a lot of trouble to go to for a few measly strips!

Maybe by number 16 I will have cracked it!