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granger
02-10-2015, 02:09 AM
I have built an even dozen stringed instruments and have just completed my second ukulele. Reflecting back on the experience I can offer two ideas that may make a first time build a little easier. The two aspects of the build (not finishing, that is another animal) that perplexed me the most where 1. how thick should the top be and when do I stop carving the braces to affect good tone??? and 2. getting the neck on right/straight to promote good action, playability, saddle height.
There are many ways to solve these 2 problems and my ways worked for me and produced very nice sounding instruments with excellent action on the very first build.

To solve the how thick the top/when to stop carving the braces I used the method recommended by Dr. David Hurd of Kawika ukes. I bought his book Left Brained Lutherie and it is a pretty technical read, but his web site explains the method in straight forward terms under the section on measuring top compliance. I can not recommend this approach highly enough!!! It is really pretty straight forward, easy and does not take much time once you build the simple fixtures.

Here is a picture of the simple fixture and inexpensive dial micrometer I used on the latest build. 75958

Steps: Once the thicknessed top and roughed in braces are attached to the sides without the back on, you can begin taking compliance measurements. I use a 2 lb weight. At first I thin the top around the rim about 10% of its thickness, from the rim in about 2". Then I slowly begin to carve the braces until I get deflection values of about 0.006". Finish sanding the braces and you are done. The results have been very good thus far.

The second problem of neck alignment was dealt with by simplifying the neck construction. I made a heel-less neck very similar to that of an electric guitar neck. Perfect alignment was very easy to accomplish. Some will not be able to stomach the aesthetics. But I build for myself and only need to please myself. Routing the pocket into the body with a simple router template and routing the neck end with a template is a breeze. final adjustment is simplified and glue it in!
Here is a picture: 75960

Here is the finished instrument: 75959

Hluth
02-10-2015, 03:01 AM
Experience is the best teacher. If your finished uke lacks volume, then your top is probably too stiff. If the bridge begins to rotate more than just a little bit under load, then your top isn't stiff enough. Make adjustments on your next build based on this and eventually you will achieve a benchmark. The neck angle should put the top of the frets and top of the bridge without the saddle on the same plane. Always error towards a negative neck angle (never "bowed"). I also use pocket joints and have an article about them that might interest you. You can find it here: http://hoffmannlutherie.com/luthier/neckjoints.pdf

granger
02-10-2015, 03:45 AM
Thanks for sharing your work with pocketed necks, I learned several things. I build with a reverse heel. I like the way you dressed the top of your reversed heel block with a piece of accent wood, nice touch.