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Questions: Fret Shape and Tonality

Questions: Fret Shape and Tonality

Originally published in American Lutherie #76, 2003

 

R.M. Mottola of Newton, MA answers Earles L. Mc Caul’s question regarding the effects of guitar fret shape upon intonation and tonality.

The short answer is no effects whatsoever. There is a good (but highly technical) article on this subject by Steve Newberry in The Big Red Book of American Lutherie Volume Two, p. 106, “Fret Crown Radius: A Cause of Pitch Error?”

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Sharpening the Stellite Teeth on the 3″ Hitachi Blade

Sharpening the Stellite Teeth on the 3" Hitachi Blade

by Bruce Creps

previously published in American Lutherie #91, 2007

See also,
“Resawing Lutherie Wood” by Bruce Creps
“Grading and Curing Lumber” by Bruce Creps



With a shop-made jig you can sharpen your blade in place in less time than it takes to remove and reinstall it. You save money, conserve steel, and don’t need to fuss with fine-tuning a newly installed blade.

I sharpen blades ten times, making my “cost per blade” under $13. I discard the blade after that because I have found cracks on a few blades after 12–15 sharpenings, and because the Stellite teeth taper in width so you lose set when you sharpen the teeth down to nubs. With insufficient set a band can rub the stock and heat up or wander. The blade will generally stay sharp for eight hours of production sawing of dry hardwood. I don’t go much beyond eight hours because a less-than-sharp blade may heat up and work harden the Stellite tips.

The all-Stellite blade has a cutting (rake) angle of 22°, a sharpness angle of 50°, and a back (clearance) angle of 18°. For my purposes this blade is just right. I once used an alternate-tooth Stellite blade and got better performance when I increased its cutting angle from 16° to 22°. Otherwise I have not experimented with tooth geometry.

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Curing and Grading Lutherie Lumber

Curing and Grading Lutherie Lumber

by Bruce Creps

previously published in American Lutherie #92, 2007

See also,
“Resawing Lutherie Wood” by Bruce Creps
“Sharpening the Stellite Teeth on the 3" Hitachi Blade” by Bruce Creps



At a GAL Convention several years back a well-known luthier and lecturer stated that the best way to be assured a supply of properly processed tonewood was to harvest and air dry it yourself. He posited that due to turnaround and financial considerations most tonewood suppliers rush their kiln schedule and compromise the quality of the wood. For me, the wisdom of his statements was in stressing the importance of proper drying.

I don’t know if the percentage of kiln-dried instrument-grade wood damaged or compromised due to improper drying is higher than the corresponding air-dried percentage. I do know that it is very easy to damage wood when air drying it. You don’t have to do anything. Neglect it and you can expect degrade: end checks, surface checks, warping, case-hardening, rot pockets, fungal stain and decay, and/or insect infestation.

Improperly kiln-dried wood can exhibit checking, warping, and case-hardening. However, with kiln drying the fungi and pests in the wood will be killed, and colors can be clearer. The obvious disadvantages of kiln drying are that you need space and funds for a kiln, and you use lots of energy (unless you have a solar kiln).

Become A Member to Continue Reading This Article

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.

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Constructing the Middle Eastern Oud, Part Two

Constructing the Middle Eastern Oud with Peter Kyvelos, Part Two

by R.M. Mottola

previously published in American Lutherie #95, 2008

See Also,
“Constructing the Middle Eastern Oud with Peter Kyvelos, Part One” by R.M. Mottola



The Top

The top of the oud is “flat” and features ladder bracing and one to three sound holes with fretwork rosettes in them. However, the top is constructed to either passively encourage or actively shape the kind of bellied-in-front-of-the-bridge, humped-up-behind-the-bridge distortion common to all instruments with string anchors at the glued on bridge. More on this in a bit.

Peter uses German spruce for his tops and he generally joins and then thickness sands tops well in advance of building, inventorying the joined tops for years before actually using them (Photo 1). Finished top thickness will average around 2MM, depending on the stiffness of the wood, so tops are thickness sanded accordingly at this point.

The first steps in preparing the top are to cut it to shape and then mark and cut channels for the sound hole purfling (Photo 2). He uses a custom made fly cutter to cut the channels. His purfling scheme is pretty simple, and he generally uses black and white fiber violin purfling strips for this. The ends of the purfling strips are mitered and dry fitted before being glued. There is no fingerboard extension to hide the butt joint, so this work is a bit finicky (Photo 3). The purfling is glued into the channels and then scraped down once the glue dries. Then the sound holes are cut out.

Become A Member to Continue Reading This Article

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.