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Router Jig for Shaping a Neck

Router Jig for Shaping a Neck

by Mike Nealon

Originally published in American Lutherie #62, 2000



This jig is designed to carve a guitar neck with a constant thickness of 5/8" from the nut to about the 10th fret. The shaft of the neck has a circular cross section and is cut so smoothly that only a minimal amount of finish sanding is required. To carve a neck to this shape profile while also tapering the neck width requires that the neck billet be placed at an angle to the axis of rotation, shown schematically in Fig. 1. These particular necks, which I make for thin-body (2 1/4˝) acoustic guitars, are cut to the specifications found on the Martin dreadnought blueprint (except for the taper and the length of the heel). Since the heel is only 2" tall, the router can pass over the top of the heel. The necks are 14.05" long from the nut to the body; the region of constant thickness is 11 1/4" long, leaving 2 3/4" for the curve of the heel.

The jig is made in two parts separately mounted to a base plate: an inclined router table, and a rotation stage. The router table shown in Photo 1 is a wooden box on top of which will be a template to guide the router along a straight line. The rotation stage consists of a long narrow wooden platform, Photo 2, into which will be embedded a steel rod. The rod acts as the axis of rotation and is parallel to the base plate. The top of the rotation stage is tapered at the same angle as the router table. The neck billet is clamped, fretboard surface down, to this platform.

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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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This article is part of our premium web content offered to Guild members. To view this and other web articles, join the Guild of American Luthiers. Members also receive 4 annual issues of American Lutherie and get discounts on products. For details, visit the membership page.

If you are already a member, login for access or contact us to setup your account.