Six braces instead of four on a dreadnought is an effort to maintain the integrity of the arch in the back (15' radius).
The quited maple in this back came from a luthier/friend in Ames, IA ... thanks Arkady.
May is here and it's time to start spraying lacquer. Check here next month to see the finishing progress. Also, I have a couple of guitar bodies that, hopefully, will be assembled by the end of May.
Stay on key and on the beat... and get up early.
First of All...
Congrats to University of Virginia basketball for winning the men's NCAA basketball tournament. That was sooooo very cool. Wahoo Wah!
Cutting a radius dish on a CNC is fairly straight forward. The size and capabilities of the machine are the limiting factors. Two limitations with Woody's CNC (NextWave HD-4):
It can only cut over an area approximately 16" x 24". So, only half of a 24" x 24" radius dish can be cut at one time. That's not really a big problem.
Also, on this relatively inexpensive CNC, the router travels along a programmed toolpath which can only change direction in the X or Y plane (unless one creates a 3-D model which is more complicated than we can get into right here). Each toolpath, therefore, maintains the same Z elevation throughout the cut.
As a result of these two machine characteristics, 121 concentric semi-circular toolpaths had to be created, each a 2.5 mm smaller radius (from outer to inner) and each at an incrementally different Z.
First, one must calculate change in Z from one radius to the next. The Vectric software is quite capable of creating the drawings and measuring the incremental Z changes in a segment of a 15-foot arc. The challenge is to manually input 121 toolpaths without error. It's just very tedius. The final arc (cut into MDF) is produced in 121 micro-terraced steps.
Scrimshaw Rendering of Denali
(aka Mt. McKinley)
Woody had five scrimshaw renderings made with various Alaskan themes for guitar inlays when Woody Strings operated in Fairbanks, AK (1975-85)... still got 'em.
The same procedure is used to cut the soundboard radius dish (35 foot radius). The alternative is to buy two radius dishes at ~$125 each.
Today is May 1. I will be back tomorrow to say a few things about the photos below. Thanks for tuning in..come back.
Woody's four-piece back is built for aesthetics (mainly) and acoustics (a little). Building 1/3 of the guitar's back out of maple, takes the edge off the sound of an all-rosewood guitar... but it's more work.
THE MINI: The Mini guitar that was started in March was completed and set up in April. It still needs a date with the finishing booth.
It's a very sweet little guitar. I like it a lot and will be sad to part with it (someday). The maple back and sides mute the edges on the tone of the Mini so it plays very clean and easy to punctuate single notes...more for jazz than for grass. I will build more of these.
The back and sides are of spalted maple and will be striking under a finish.
Woody got a wild hair one day and made about 50 of these guitar clamps . They're so easy to make. I think that it took about 3 hours total with a 1" poplar dowel, a centering jig on the drill press, 50 wing nuts and washers, 24 feet of 1/4-20 all thread, and an eighth-inch sheet of cork from Michael's. I've always wanted a full set of these. They will be useful.
In April Woody finished carving the top and back braces for the next two guitars. On a hand-made instrument, braces are always carved in place. This allows the builder to modify the stiffness of the top and back relative to the density and stiffness of the wood in each brace. Woody uses a 25 mm, #5 sweep Swiss gouge.
The results, when cut with a ballnose router bit, are quite satisfactory.