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Twist in linings at the waist?
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Author:  burbank [ Wed Jan 10, 2007 4:57 pm ]
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I'm contemplating using reverse-kerf linings on my current guitar, but can't
figure out how to deal with the twist that the linings want to make at the
waist due to the side profile especially on the back part. With conventional
linings, I just broke the lining in shorter pieces to compensate and maintain
good contact with the sides, but don't want to lose rim stiffness by breaking
if I use reverse-kerf linings. It's the same thing that happens with bindings
at the waist that sometimes requires extra clamping. What do you who use
reverse-kerf linings do?
Author:  Dave White [ Thu Jan 11, 2007 12:55 am ]
Post subject: 
Pat,

I'm not sure quite what the problem you have is. If you mean that the waist is a tight curve so that the kerfs close together at the side's waist and still leave a gap between the side and the lining, then cutting a few extra kerfs in the lining in between the existing ones in the waist area lets the linings bend to a tighter curve and contact the side. Like this (done very crudely and quickly to illustrate):



If you mean that the side profile to accept the domed top and back means that the lining doesn't stay in line with the top of the sides everywhere when presented flat to the sides then glue it as a continuous strip so that the top of the lining at the highest point of the sides is slightly proud to allow for sanding to fit the top, and it is flat against the sides everywhere. At the lowest point of the side profile the lining will be proud the most. Then just sand it down back to the side profile for the top and back fit as normal.

Hope this makes sense.
Author:  TonyKarol [ Thu Jan 11, 2007 1:19 am ]
Post subject: 
I start with the linings about 1/8 high at the neck block - mine are about 3/4 tall to start - then when you get to the waist they are even with the side.
Author:  Colin S [ Thu Jan 11, 2007 1:34 am ]
Post subject: 
I've never found it to be a problem. I always slightly wet the reverse kerf linings on the outside to make them more flexible and less likely to crack when I'm installing them. There seems to be enough flexure to allow for the 15' dome

There is enough elasticity in the damp wood to go round the dome, the kerf closes up slightly at the bottom to allow for the dome as you can see.



Colin
Author:  letseatpaste [ Thu Jan 11, 2007 2:45 am ]
Post subject: 
I had a terrible time with reverse kerf linings on an 0-size parlor. I kept getting gaps at the waist. I finally gave up and went to regular kerfed linings installed in about 4" sections, worked wonderfully.

I wonder if it's more of an issue when the waist is a bit tighter, because I didn't have a lick of trouble when I used it during the Fleishman class, but it wasn't a very tight curve.
Author:  Pwoolson [ Thu Jan 11, 2007 3:08 am ]
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As Tony said, leave them a tad high at the ends and they will lie more flat. Assuming they are taller than a traditional lining, it's not going to hurt anything to grind some of it off when you put it on the sanding dish. I do this intentionally for asthetics. I think it looks cool and accentuates the dome of the back when you can see the "wave" in the linings. Though my linings are taller and much more rigid, I think you could do the same thing.
Author:  burbank [ Thu Jan 11, 2007 6:28 am ]
Post subject: 
Thanks for the great input, gentlemen!

Dave, your second paragraph is what I was after. The extra cuts are a great idea.

I'll try the water torture method and also gluing more proud. Ironic that I'll glue it highest where it needs to be dish-sanded lowest, eh?
Author:  Rob Girdis [ Thu Jan 11, 2007 8:22 am ]
Post subject: 
I just made some linings last night, so I will show my take on this. I like to profile the linings to match the curve, or dome, of the sides. When they wrap around the sides, they follow the countour and there is no twisting.
I use a flat template of the domed sides to draw two parallel lines on the lining stock. I cut the bottom of the lining first, then plane it to the line and clean it up, and let the other edge stay proud a little for trimming after they have been glued. Then I kerf the linings individually with a band saw by setting up a stop block behind the blade to control depth of cut.
The photo shows the finished piece.
Author:  LanceK [ Thu Jan 11, 2007 8:27 am ]
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That is too slick Rob!

Hey good to see you here again!
Author:  Serge Poirier [ Thu Jan 11, 2007 9:32 am ]
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Great idea Rob!
Author:  burbank [ Thu Jan 11, 2007 10:26 am ]
Post subject: 
Rob, what an elegant solution.

Hesh, that's a a great tip.
Author:  Rob Girdis [ Thu Jan 11, 2007 12:53 pm ]
Post subject: 
My early years in lutherie were spent sharing a shop with a shipwright. He was builing a traditional 52' schooner for himself right outside my shop window. It was watching him fit a replacement plank into the hull of and old boat that it dawned on me that I could adapt the same technique to fitting the linings. I was using solid linings then, so this worked well for that application. Then I went to reversed kerf linings and it worked there too. Now I have settled on traditional linings and it is still my favored method.
The longer I build the more towards traditional I seem to get..    
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