LUTHERIE

Step 8: Assembling and Attaching the Soundboard

The soundhole of the uke was marked off with a compass and a hole was drilled in the center for the pin which will be our registration point for both the cutting of the rosette channel and the soundhole. I used the soundhole dimension, 2 1/8", listed in my Martin book for a concert uke. The rosette channel is 1/8" outside of that. I cut the channel in the same manner as the backstrip, but used a homemade compass to do the scribing. This compass, made from a wooden popsicle stick and an exacto blade, came from Cumpiano's book and is a classic case of simplicity being the ultimate sophistication. Nothing could be cheaper, easier or more effective.

My registration pin, a small nail with the head cut off, is hammered into my workboard and extends through the hole in the center of the soundhole radius. The popsicle stick, with a small hole in its tip, rotates around this pin. Measuring 1 3/16" from this hole, I inserted the exacto blade through the stick until it protruded about 1/16". I then scribed gently around the pivot, increasing pressure with each revolution. when the blade bottomed out, I shifted it 1/8" outboard and scribed the outside line of the channel.

I placed masking tape over the area and rescribed my lines, cutting through the tape and removing the tape between the lines. This will help prevent tearout outside of the scribed lines, I then chisled the channel as with the backstrip. Care must be taken when going across the grain - this is where tearout will most likely occur. I discovered that reversing direction will sometimes make the cut less problematic. It also helps to re-scribe your lines every now and then, which serves to clean up the edges of your channel.

When using wood purfling in tight curves such as this, I found it difficult to bend without the strip turning on end - that is, angling into the curve. I experimented with several pieces by soaking them in hot water and fitting them in a "practice" rosette channel that I had chisled in scrap mahogany. At least twice, the strip came apart from too much soaking and too tight of a bend. Finally, I hit on the right length of time for the soak - 30 seconds ­ and I was able to fit it into the channel without breaking or twisting it. I then placed another piece of wood over the rosette and clamped this sandwich in the vise overnight. I left the rosette in the practice channel until I was ready to inlay it in my top plate.

Since then, I have learned the trick to bending purfling into tight curves: you split the purfling along the center line, stopping just before the end - that is, leaving the last inch or so unsplit. It can then flex more easily, without twisting, and when glued in place it appears whole.

When I was satisfied with the depth and evenness of my channel, I test fit the purfling and then glued it in, placing a piece of wood on top and weighting it down. I positioned the gap at the ends of the purfling at the top where it would be covered by the end of the fingerboard. When the glue had dried, I scaped the rosette flush as with the backstrip, finishing with sandpaper.

Cutting out the soundhole was simplicity itself. Using my popsicle stick compass, I adjusted the blade for a 2 1/8 diameter cut and scribed along my pencil line, going deeper every two revolutions or so until I cut through. I reserved the cut-out center piece so that I could refit it into the soundhole to hold the top plate in place while I fit and installed the bracing.

I went ahead and installed the kerfing strips for the top at this time. The soundboard on this uke will not be domed like the back so no sanding to angle the kerfing and sides was done. Guitars sometimes have a slight dome to their tops for extra strength - especially those that use steel strings - but it is not necessary for our concert uke.

Because of the arch to the back, it was necessary to shim up the edges all around when fitting the body back into the mold. I also had to reinstall the blocks at the waist to keep the sides perpendicular before gluing on the soundboard. But first, the bracing had to be fitted.

I fashioned a soundhole reinforcement plate from scrap 3/32" mahogany first, then cut 3/8" x 1/4" strips for the braces. I profiled these on the belt sander and ramped the ends before gluing them in place. My bracing pattern is a modified Torres clasical guitar layout that I found in the LMI catalog/manual. The fan braces are notched to go over the bridgeplate. I gambled that these two braces and the plate would give the soundboard sufficient strength to resist the pull of the nylon uke strings, but with a top this small and the relatively light pull of the strings I think it will suffice.

Notice that I installed the neck mounting bolts, running them out until they were a scant 1/16" below the level of the exterior. I carefully experimented with various ways of tightening them up later through the soundhole. I settled on a 1/4" drive ratchet with a 1/4" socket holding a 3/16" allen bit. I practiced with the soundboard sitting on the sides, working through the soundhole until I was certain that it could be done. I could have installed the neck onto the body before closing it up, but the neck is still rough and I wanted to finish the body before turning my attention to that very critical step.

I created a label on my Macintosh and glued it over the backgraft to be seen through the soundhole. It is a conceit, I suppose, for a first effort, but I wanted my Uke to have a professional appearance. The Scottish harp or cruit, is the basis for the name McWhorter. It was originally MacCruiter which means "Son of the Harpist." Not a bad name for a fledgling luthier!

The model designation, UC-3 is for Ukulele - Concert - Style 3. The style numbers are based on Martin's uke models. Because I have chosen to adorn my uke with binding, wood purfling, and MOP dots, it would be a mid-range model, style-wise. A Style 1 would be very plain, and a Style 5 would have pearl or abalone in the rosette, purfling and fingerboard.

It is important, in my opinion, that non-toxic, eco-friendly materials should be used if at all possible. Honduras Mahogany is somewhat exotic, to be sure, but so far non-endangered. TiteBond glue is non-toxic and water soluable, and the water-based laquer used for the finish is non-toxic and can be safely poured down the sink drain. The oil finish used on the fingerboard and bridge is a mixture of tung and linseed oils which are organic and also non-toxic. excuse me, I have to go hug a tree now...

I carefully vacuumed out the interior of my uke and prepared to install the soundboard. This was a big moment for me, and I wracked my brain for steps that I had forgotten before I began this irreversable procedure. Unable to think of any, I ploughed ahead.

After test fitting the clamps and checking for gaps, I spread TiteBond on the kerfing and glued the soundboard down. Pieces of cork underneath the back protected it and provided shims for the arch. After and hour I released the clamps and was pleased to see that the seam was better than it had been for the back. I trimmed the overhang with my dremel router as before and touched up with sandpaper. The body was complete!