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Conical Fretboard Radiusing Jig

Conical Fretboard Radiusing Jig

by Mike Nealon

Originally published in American Lutherie #66, 2001



How flat does the top surface of a fretboard need to be? A good working estimate would be to equate the tolerance to the gap between the top of the 2nd fret and the bottom of a string fretted at the 1st fret. The tolerance must be less than this gap or the 2nd fret will come into contact with the string. With the bottom of the open string about .01" above the top of the 1st fret and about 1/16" from the top of the 20th fret, the gap between the fretted string and the top of the second fret is about .005".

Making a hardwood board flat to within .005" is not too difficult using ordinary woodworking tools. The router table and movable plate described here will produce a machine-carved surface smooth enough to require only a minimal amount of sanding or leveling.

Photo 1 shows the jig fully assembled, with the router. Photo 2 shows the jig partially disasembled to show the function of the parts. The conical fretboard made with this jig has a 10" radius at the nut, flattening to a radius of 16" at the last fret. The fretboard blank is 3/8" × 2 1/2" × 21", and is flat on one side. The finished fretboards are 7/32" thick at the crown, and taper from 1 11/16" at the nut to 2 3/16" at the 12th fret (12.670" from the nut).

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Frets and Fingerboard Care

Frets and Fingerboard Care

by Randy Stockwell

Originally published in Guild of American Luthiers Quarterly Volume 7, #2, 1979 and Lutherie Woods and Steel String Guitars, 1998



Neck Shapes. I credit Leo Bidne for his perceptions of the relationship between the fingerboard bow and the string’s motion. I use heat treatment to obtain these results when the problems are severe enough. But I find that most instruments, while needing some neck curve help, are not in serious enough trouble to merit the use of heat. Most can be put in the proper curvature through careful and diligent fret dressing and tension rod adjustment (granted sufficient fret height to begin with).

When the frets are too low or the curve too great, refretting is usually called for anyway. The fingerboard itself can then be reshaped to the suitable curves. Of course, if the fault is bad enough to call for a major removal of wood, I definitely resort to heat, neck resets, major neck rebuilding, and so on. Even after heat treatment, I find it necessary to finish with fingerboard and/or fret-dressing procedures.

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Applications of the Silicone Heating Blanket in Violin Making

Applications of the Silicone Heating Blanket in Violin Making

by George Borun

Originally published in American Lutherie #34, 1993 and Big Red Book of American Lutherie Volume Three, 2004



In American Lutherie #25, Mike Keller describes how he uses silicone heating blankets for bending guitar sides, and mentions an earlier article in Fine Woodworking. The potential of these devices for use in violin making became obvious to me, and with some experimentation and adaptation, I’ve developed specific applications for the violin maker.

Silicone heater blankets, also called flexible heaters, are available from two sources, with a number of standard sizes in stock at each company: Watlow Electric of St. Louis, Missouri (www.watlow.com) and Benchmark Thermal of Grass Valley, California (www.benchmarkthermal.com). Watlow markets through distributors. They have a large selection of stock sizes up to 35" long. Benchmark has a smaller stock size selection, but their prices are considerably lower. They will make any size you wish, but that adds to the cost and delivery time. Stock maximum length is 20", but this is more than long enough for violins. In bending bass ribs, I use two 10" wide blankets for the longer pieces, and only one for the center bout. The best units are 4W/sq.", rather than the 2W models. This type will get up to 500°F in a couple of minutes. Product catalogs are available which list the various sizes.

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Blackboard Eraser Polisher

Blackboard Eraser Polisher

by Michael Dresdner

Originally published in Guild of American Luthiers Data Sheet #288, 1984 and Lutherie Woods and Steel String Guitars, 1998

 

I’ve been using a blackboard eraser to do final dressing on my frets. I take this nice soft eraser and a piece of 600 paper and go across the fretboard. It’s beautiful; it just follows the curve and gives you a nice even rounded top. This is for polishing, after you’ve shaped the frets with files. ◆

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Tuning the Guitar

Tuning the Guitar

by Ian Noyce

Originally published Guild of American Luthiers Data Sheet #56, 1977 and Big Red Book of American Lutherie Volume One, 2000



Because the guitar has fixed frets set to an even temperament, tuning it properly is not the cut-and-dried process that many people believe. And due to various factors that we’ll get to shortly, if the guitar’s bridge is placed exactly where the nominal scale length says it should be, the instrument may not play in tune at all.

The two most common methods of tuning are: (1) the 4th- and 5th-fret method and (2) the harmonic method. Both of these methods are often misunderstood through confusion regarding perfect (or Pythagorean) intervals and even-tempered intervals.

The 4th- and 5th-fret method. Theoretically, this is the simplest method as it simply involves tuning unison intervals. The A string can be tuned to an A tuning fork, then the bass E is fretted at the 5th fret and tuned in unison with the open A. The D string is tuned in unison with the 5th fret of the A, the G string is tuned to the 5th fret of the D, the B string is tuned to the fourth fret of the G, and the high E is tuned to the 5th fret of the B. In practice this can be difficult because any errors are cumulative. It’s also true that many guitars tuned this way will not play in tune in all keys.

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