Building a Guitar with William Cumpiano Page 3
Tools and Technique
We layed out template outlines and bracing positions directly onto the top and after the glue set and dryed, proseeded with carving.
One of the "ah ha" moments I had was a technique Mr. C. showed during assembly of the block, sides and back. This was the missing piece for me in terms of a proper neck set and although the procedure has been explained on his website, I needed to see it first hand to "get it".
It starts with the block prepared for excepting the neck tenion interface. For this project, I had one more complication with the block. I wanted to have the cutaway side meet the taper of the heal. In order to have that angle correct, the cutaway curve must be built into the block.
Once you have the top braced and ready to glue on the block, you must ramp the glue surface about 1/32" from square as measured from the front of the block. This will put a slight hump in the top precisely were the fretboard rests against the top, closing the gap that would have been there to achieve the proper neck set angle.
To get the hump with the proper neck angle though, you also need to hold the block tilted back during the assembly of the sides and the back. To hold this 1/32"back tilt, a Shoe is used that also holds down the top to the workboard at the same time. All these little ramps and tilts are what make the difference in ending up with a tight neck/body joint and the proper neck set for string action.
[Note; It’s not the “sloping ramp” that gives you the 1/32 inch gap on the next image. The slope actually makes the block lean forward. But, it’s the “Shoe” that holds the block back at a slight angle yielding the 1/32 inch gap. The block is bolted to the shoe through one of the holes in the “blot-on” system of the block.]
So the key to this system is the Shoe; the way the shoe clamps down the top to the workboard and the way it holds the angle on the block simultaneously. All this clamping also helps to keep the body securely attached to the workboard especially when working on the sides in preparation for gluing on the back.
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