Tuesday, October 12, 2010

CNC router to make Guitar - World’s First Serviced Archtop Guitar Kit

Fernando Alonso Jaén, a Spanish guitar designer, has created the world’s first “serviced” archtop guitar kit — a kit where complex wood tooling is done by the manufacturer to simplify the buyer’s task. As a small operation, “creating the wood parts with complex contours required for the guitar would have been impossible,” Jaén said. Using a CNC router he was able to do it.

World’s First Serviced Archtop Guitar Kit
The archtop jazz guitar (also called a jazzbox, cello guitar and plectrum guitar) is a steel string acoustic guitar with a big soundbox somewhat like a cello; it is usually electrified.
“Despite the growing popularity of archtop guitars, no one has ever tried to make a serviced archtop guitar kit before,” says Jaen. “I have had to overcome many obstacles along the way but the biggest was reproducing the many complex geometries involved.”

Conventional woodworking would have required lots of hired hands. “The cost would have probably been more than the market could bear,” says Jaen, and it “also would not have achieved an acceptable level of accuracy.”

Computer numerical control (CNC) machining provided the answer. “All the available CNC machines that I saw here in Spain were too big,” Jaén said. Others were either too smaller or large. “I found the exact size and style of machine I was looking for in Techno’s LC series,” he adds.

Jaen used RhinoCAM software for both the CAD and CAM tasks — to design the archtop guitar kit and to create the CNC program. The kit includes the top with braces carved in it and the f-holes and pickup already cut out. “Carving the braces is feasible only with a CNC router,” Jaén says. “This relieves the maker of a difficult job — adjusting two wooden bars to the curvature of the top so that when they are glued the glue line is almost invisible.”

Quarter-Sawn Spruce and Maple
Spruce wood, light, stiff and quarter-sawn through the center axis of the tree, is used for the top of the guitar. Quarter sawing produces wedges, two of which are glued along their thicker sides. “A good top must have compact wood growth rings,” Jaén says. “The closer the rings are, the stiffer the top.” The back of the guitar is curly maple, also quarter sawn to better display the back’s curl and provide greater stiffness.

“The back in a serviced kit must be delivered in the final shape,” says Jaén. He bent the sides using a machine he designed and built with the CNC router. “Curly maple is one of the hardest woods to bend but this machine handles it easily. I couldn’t have made the machine without the CNC router.”

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