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I just attached koa sides to a spruce top. This is a uke with Spanish heel.  When I released it from the jig the top was pulled out of plane.  I never had this problem with hardwood tops.  Will putting on the back pull it back level?  The high point on the side profile is 2" back of the waist.  Its 1/4" inch higher than at the heel.  I could also lower the butt block a 1/4" if that would help pull the soundboard level?  Need advice!

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A higher purpose for wood.
Rich Smith
Issaquah, WA

Are you building using a work board or an external mold? I dont generally take my classicals off the workboard until the back is glued on. It sounds like your sides might be flexing a bit and affecting the top arch.

I thought the same as Martin. It sounds to me as if your sides come out of square during the clamping operation and bounce back to the their original shape when unclamped, distorting the top in the process.

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Jim Watts
http://jameswattsguitars.com

Yes I am using a workboard with waist cauls.  Otherwise its an open workboard.

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A higher purpose for wood.
Rich Smith
Issaquah, WA

It sounds like youre building your uke exactly the same way I do my classicals. I'd definitely leave the guitar on the workboard with the side supports in place and the soundhole clamp also in place if you're using one. I also have a seperator bar supporting the sides at the waist. This stays in place until after braces have been trimmed and back has been test fitted.

Thats right Martin. With everything clamped down things are straight. Just hoping that the back once its attached will keep things that way.

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A higher purpose for wood.
Rich Smith
Issaquah, WA