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an3
11-20-2015, 06:24 AM
Hi luthiers,

I'm hoping to get some expert advice as I've hit a road-block on my first uke build.

I'm making a 6-string guitalele and so far things have been going very smoothly. After setting the sides to the neck however I'm no longer so sure about it...

Essentially, the body has become warped relative to the neck. The neck/top have not remained flat relative to each other (they are in a bit of a "V" shape, pivoted at the heel) and the tailblock/neck centre line have also not remained straight. See the attached photos to get a better idea.

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In the bending stage, the sides were definitely not perfect (the one had a bit of spring back after having been removed from the mould) but they seemed adequate anyways - they were both quite square. Tapering for the back plate was done afterwards.

I used a spanish heel for the neck joint and I squared/straightened everything using a side-mould jig before gluing. It did take a bit of force to do this though. And whereas everything looked fine while in the the mould, when taken out there was obviously some spring back.

So my question is: will this warping "come out in the wash" when I attach the top and back plates or do I need to somehow sort this out beforehand? Obviously I'm concerned about the added tension in the body, especially since it's already wanting to pull in the same direction as the strings.

Any advice and recommendations that you can give will be greatly appreciated. I'm really hoping to salvage a couple hundred hours worth of work!

Thanks in advance :)

Michael Smith
11-20-2015, 07:10 AM
You are ok. When you attach the back and top you will be able to adjust the neck angle. I would not worry about "added tension" You are in good shape.

RPA_Ukuleles
11-20-2015, 07:16 AM
You should be able to correct the angle and alignment "during" the glue up. If you glue the top first and get the neck alignment straight by using your mould, the top can correct and hold the alignment. Then when glueing the back, clamp the body/neck flat to the bench and perhaps even a 16th" spacer under the nut to give you a slight amount of angle (in the preferred direction) The glueing of the back will then hold the angle in place. Sometimes for a repair to a bad neck angle a luthier will "slip the back" to correct the angle. Essentially, unglue the upper bout perimeter of the back, clamp the angle into position, then re-glue the back. This holds the new angle in place. You will essentially be slipping the back during construction. You may consider spritzing the sides to soften a bit while you are forcing them to the correct alignment. They can then dry in the corrected shape.

an3
11-20-2015, 07:25 AM
Fantastic - thanks so much for your help fellas! I'm super happy to hear that it's not a do-over :)

Allen
11-20-2015, 08:46 AM
The more traditional way to build with the Spanish Heel method is to glue the soundboard to the step in the neck block first and then the sides are slipped into the slots and glued down to the soundboard. Then you install the innings. This all done on a work board that will hold all these parts in their correct alignment.

You can still work around the issues you have, but the above for future reference.

Hluth
11-20-2015, 10:42 AM
Although I don’t use Spanish heels, I do align the neck and body early on in all my builds. This can be pretty tricky, because just a little twist in your sides, or non-symmetrical bouts can throw the neck out of alignment. I sometimes use a brace CA glued to the heel block and pinned to the tail block to keep the sides from moving when the top is glued on. It can also be used to pull the tail into alignment with the neck, but it will make the body non-symmetrical if it was right to begin with.

To check the vertical and lateral alignment of the neck to the body, I made a square (shown in the pictures on a finished ukulele). My sides are made wider (taller) than needed so I can mark them using this square, then I draw and finish to a line. In your case the sides are too tall at the tail and can be marked and trimmed to align with the neck. Be sure to also use the square to mark the bouts so they align laterally with the neck. All this is usually done before the linings are glued in, so you will have to sacrifice some of your lining to correct neck angle.

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BlackBearUkes
11-20-2015, 03:07 PM
Just to be clear, it might be best not to refer to the kerfing as linings. Linings are generally solid bent pieces glued to the sides, making the sides stiffer in the long run. Kerfings are very flexible and normally only offer more gluing surface for the top and bottom, not stiffness. I don't mean to preach, only clarify.

Hluth
11-21-2015, 05:28 AM
Thanks for the clarification. Kerfing is one of the words that is in the luthier’s dictionary but not in the Webster Dictionary. Stewmac actually calls them “kerfed linings” on their web page. Kerfing sounds like “to kerf” or the act of making kerfs in a lining. Good thing is: whether they're called linings, kerfing or kerfed linings, fellow luthiers usually know what you’re talking about.

an3
11-24-2015, 11:23 AM
FYI - Should anyone else runs into this problem, I wanted to update to let you know that gluing on the soundboard did completely square everything up. It worked great!

Thanks again for taking the time to help me out :)

sequoia
11-24-2015, 05:17 PM
Thanks for getting back. I found myself thinking about your predicament a lot. I figured wrestling that rascal back into shape would probably fix things. I love happy endings when it comes to ukes. I've experienced a few unhappy endings myself. Grim's fairy tales for ukuleles. I don't want to talk about it...

Michael N.
11-25-2015, 01:08 AM
Do you love happy endings when it comes to guitars though? :eek:
I once made a Guitalele using a very similar method of construction. The difference being that I glued on the back bars and the 2 soundboard bars onto the rib structure/linings before removing the assembly from the mould. The idea was that the glued in bars would help maintain the shape of the sides, which I guess they did. The whole thing was pretty rigid. The soundboard was glued on. The back glued on last, similar to the method that Torres used to glue the backs of his guitars. I'm not sure that I would use the method again but it certainly was a different way of doing things.