Saturday, January 18, 2014

Acoustic Progress -- Part Three

After leaping into the acoustic guitar building arena, there was ample activity in creating jigs and tools especially associated with the project.  I could have avoided this if I was lazy, incapable, or willing to spend money like a drunken sailor (oops, now I've just pissed off my military friends in the middle east, whom I've gifted with guitars and amps).  Commercially crafted tools are expensive, but no more useful than what I have had the enjoyment of creating, and lots of beer money left for me.

You've already seen some of the tools in a prior post, but here are a couple other shots of special stuff.

I've learned there are a couple ways to attach the top and back of the guitar to the finished sides, and one of those ways is to use clamps such as the one shown here.  It's a simple screw-type arrangement with cork-faced 1-1/2" x 3/4" wood blocks drilled to accommodate a 8-inch threaded 1/4" shaft with rubber pieces to protect the surface of the guitar. Washers and a wing nut completes the job.  The clamp is placed against the guitar side, when the glued top or back is in place, and the nut is tightened to apply pressure to the surface during the gluing process.  Pretty simple to build and use, and a lot less expensive than commercially available items that look and work the same.

A cabinet scraper is another essential tool, but when you live in a place that has limited supply of specialty tools, it's sometimes easier (and more fun) to create your own. I used a paint scraper blade attached to a custom handle, and voila, a useful tool.

I've been diligent about taking progress photos along the way, so that if I undertake this process again, I'll have a leg up on the project.  And, it's nice to be able to sit back and admire what these old hands have been able to accomplish along the journey.

Shaping the top and finishing the rosette around the sound hole on the outside surface was the first step.

Then came bracing on the inside of the top.  I chose to replicate the Martin guitar pre-WWII scalloped bracing that was used on the D18s and D28s, because of the deep warm sound created from this arrangement.  This process required a whole lot of research, and thanks to the web and a few vintage book stores I was able to find plans and helpful information.

Bracing for the inside of the back is a little less involved from the standpoint of style, but there is one thing that makes this a bit complex.  The back must have a slight crown to it, so the bracing has to be cut to form that crown, which is dimensional from the center to the ends.  Thanks to great layout diagrams, this was a relatively easy process.  The center wood strip is there to stabilize the bookmatched surface of the the back, which like the top it is constructed from two pieces of material glued together on the edge.

Properly shaping and fitting the sides to the required dimensions is crucial to the overall design.  If I screw this up the top and back will not fit properly, and the neck will not join the body correctly.  Here's where the body jig comes into play.  The shaped sides are placed into the body mold and carefully positioned on 'center' with the mold, and any excess material is then marked and cut to fit.  Measure twice or three times, and cut once!  There is no gluing it back together to get it right.

When the sides fit perfectly, thanks to the help of the spreaders I built, the heel and tail blocks are glued in place.  Then the lining (kerf) is glued to the top and back inside edges of the sides, which is the surface on which the top and back are glued.

I'll post more photos with explanations as progress is made.  So far, so good!  I keep my fingers crossed so that anything unexpected is 'good'.

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