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Miter Slot Sled

Miter Slot Sled

by John Calkin

Published online by Guild of American Luthiers, March 2024

 

This jig is more fallout from the week I spent in the last century in a class taught by Charles Fox. Jigs with clamps such as these have been all over my shop since then.

On top, the jig is nothing more than a panel of MDF, two lengths of 1/2" threaded rod, a pair of knobs, and two “jaws” cut from steel flat stock. The jaws were placed in a vise and one end was bent into a slight hook with a hammer. As you will see, aluminum might have been a better choice.

The underside of the jig is nothing more than randomly placed, recessed tee nuts and a wooden runner that fits nicely into the miter slot of the table saw. The runner left the panel overhanging the blade slightly so that a zero-tolerance saw cut could be made.

All layout is done on the object to be cut. Lines are placed on the edge of the jig, clamped down, and gently run through the blade.

Rough lumber can be given a clean edge as long as the dimension is within reach of the saw blade. BEWARE OF THE BLADE TOUCHING THE STEEL JAWS. THE RESULTS COULD BE DISASTROUS! Aluminum jaws make much more sense in this context. Note that helper blocks are needed to cut tall stock, in this case a pair of ukulele neck blanks. Make the cut slowly to prevent moving the stock, especially if the blade is less than newly sharpened.

Since this is the maximum depth that the saw can cut on this jig, the threaded rods were marked for length with a piece of masking tape, then cut back with a hack saw. ◆

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Mask for Belt Sanding

Mask for Belt Sanding

by John Calkin

Published online by Guild of American Luthiers, March 2024

 

My 6×48 belt sander is my favorite and most used machines, though getting the most out of it didn’t come easy. It takes a knack to use one accurately, and that took years to develop. Perhaps most importantly, I learned to join plates and sculpt necks, saving myself scads of time over the years.

This tip is about sanding parts on nearly completed instruments. It can be dangerous because the plates are already as thin as desired. In this case I needed to take down the end blocks of a dulcimer to the level of the plates. I had already shaped the sides of the blocks using a disk sander and sanding blocks. I used a scrap of poster board to mask the plates as I took down blocks to meet the plates.

The end blocks weren’t that much oversize. A hand plane might have done this job as fast as my belt sander, But I never use handtools if a machine will do the job.

Whew! I cut it close on this one, but it’s OK. The back of this dulcimer was already thinner than I liked.

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The block on the bridge end has to be larger to make room for some sort of string fixtures. There are also blocks inside the dulcimer to support the end blocks.

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The mask doesn’t have to be fancy or cover the entire plate. Sanding the block is done in quick steps with visual checking at every step.

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No sweat this time. All of the hand pressure on the sanding belt is applied to the block. I usually keep 80 grit belts on my sander. Sixty-grit would last longer and cut faster but the scratches require more work to remove.

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The abrasive barely touched the mahogany on this end. Most belt sanders of this size come with a 9" disk sander attached, but right from the factory mine wobbled badly. It was also frequently in the way, so I dismantled it. I considered returning the machine to Woodworker’s Supply, but repacking it would have been a lot of work. They still sell this machine. If they haven’t improved I wouldn’t buy it again. Standing the belt 90 degrees to the supplied work table turned out not to be a big deal, so I didn’t miss the disk sander very much. ◆

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Novice Notes

Novice Notes

by Donald Curry

Originally published in Guild of American Luthiers Quarterly, 5, #3, 1977



Editor’s Note: This column marks the last of the regular “Novice Notes” series which has run in the GALQ for a full year now. Mr. Curry assures us that he will continue to follow the Guild’s activities with interest, and I would like to take this opportunity to thank him most warmly for the excellent and reliable manner in which he has presented this informative series.

This final step in the making of an instrument is the finish, which includes preparation of the wood, applying the finishing material, and the final polishing. This subject probably has more diversity than any other in lutherie. Every luthier and every book on the subject differ as to how to produce a proper finish. Many different methods have proved equally successful and for this reason I will not go through a specific procedure but comment on some important aspects often overlooked.

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Humbucking Pickup Wiring

Humbucking Pickup Wiring

by Daniel P. Coyle

Originally published as Guild of American Luthiers Data Sheet #203, 1982



The use of dual-coil or “Humbucking” pickups enables a wide range of samples of string sounds, along with a heightened complexity of switching problems. A flexible switching installation for either 6-string electric guitars or electric basses has the ability to arrange the coils of the two separate pickups in the following configurations:

a) Pickups in either series or parallel configuration.
b) Coils within the pickups in either series or parallel configuration.
c) Coils within the pickups arranged as “single-coil” or “Humbucking”.
d) Ability to select either pickup individually or both pickups at once.
e) Phase reversal between pickups.
f) Tone control defeat.
g) The regular volume control and high-cut tone control.

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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.

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Trimming Violin Bridges

Trimming Violin Bridges

by George Manno

Originally published in American Lutherie #6, 1986



Few will argue the statement that there are no two violins the same, even if the arching, graduation, position of the bass bar and soundpost, and even the preparation of the wood may seem to be exactly the same. All violins do share some of the same properties, but each instrument has a single property of its own that distinguishes it from another. You’d be surprised what 0.1MM, either in thickness or thinness, can do to the sound of an instrument. An adjustment that minute can change the tone tremendously. Does the same hold true for a violin bridge? Yes and no.

The following is my personal expansion upon the information given in Data Sheet #224 by Alan Carruth.

As Mr. Carruth states, violin bridge tuning is a trial and error situation which is challenging when searching for an instrument’s highest potential.

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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.

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