AN EXCERPT FROM
GUITARMAKING: TRADITION AND TECHNOLOGY
By William R. Cumpiano and Jonathan D. Natelson
"SS" refers to steel string; "CL" refers to classical.
PROCEDURE: CARVING THE HEEL
Pencil, compass or French curve, razor knife, coping saw or bandsaw, wide chisel, skew knife (instrument maker's knife), fine wood rasp, scraper blade.
Stiff paper (SS only), #120-grit garnet sandpaper.
FIG.1 HEELCAP LAYOUT, SS
FIG.1-A HEELCAP LAYOUT, CL
STEP 1 - TRACING THE HEEL-CAP OUTLINE AND HEEL-CURVE OUTLINE
Refer to Fig.1,1-A and draw the heel cap for your guitar on a small piece of heavy paper. Symmetry is assured if you make a small template of half the heel cap, then align its longer edge with the centerline that was drawn previously on the bottom of the heelblock. Draw its contour on both sides of the centerline to complete the heel-cap outline. Also, draw two parallel lines at either side of the heel cap, as shown. These lines will serve as the heel-cap carving limit during the first heel-carving step. Next, refer to Fig.2,2-A and transfer the appropriate heel-curve outline onto both heelblock side faces, using a compass or a French curve.
Dive To Bottom
Fig.2-A HEEL CURVE OUTLINE, CL
STEP 2-SAWING THE HEEL PROFILE
The bulk of the heelblock that lies in front of the heel profile must now be cut away with a coping saw or bandsaw. We give instruction here for the coping saw technique: clamp the neckshaft to the table, upside down, with the heelblock facing upward. Place the headstock off the edge of the table to avoid crushing the projecting portion of the headstock veneer. Place a clamping caul under the clamp itself to avoid marring the back of the shaft.
You will now be looking at the bottom of the heel. Cut down toward the shaft, making your entering cut just 1/16 inch ahead of the heel-cap profile.
For best results with the coping saw, grasp the handle with both hands, place one foot in front of the other, and bend your knees slightly. Keeping your elbows near your sides, saw down the lines with slow, deliberate strokes, letting the blade do all the work. Twist the handle as you saw to follow the curve portion of the line. The kerf exits just shy (about 1/16 inch) of the shaft, leaving a small "step" as shown in Fig.2,2-A.
The width of the heelblock must be reduced to the width of the fingerboard by sawing, planing, or chiseling. Remove an equal thickness of material from the entire area of each face. Do not come closer than 1/8 inch from the actual fingerboard line. The reduced portion of the neckblank extends about 4 to 5 inches from the end of the neck blank.
FIG.3 INITIAL STATE OF SS HEEL (BEFORE CARVING)
FIG.3-A INITIAL STATE OF CL HEEL (BEFORE CARVING)
STEP 3 - RAMPING THE HEEL
The heel should now look like that in Fig.3 or 3-A. Study the names of the important features of the heel. We will hereafter use these terms during the heel-carving steps, as well as other procedures in this book. Now examine Fig.4 or Fig.4-A.
Clamp the neck on edge to the table or in a tabletop vise. Using a wide chisel, shave a flat, inclined plane from the fingerboard-limit line to the heel-cap-limit line. Hold the chisel at the desired angle and chisel the stock away across the grain, removing only as much each time as will leave a smooth surface for the next stroke. As you approach the heel-cap limit line, reverse direction, carving up the ramp to avoid chipping out the bottom of the heel. A fine-surfaced, angled plane should result. Repeat this process in mirror image on the other side of the heel. Do not proceed to the next step until both ramps are identical.
Fig.4 RAMPING THE SS HEEL
Fig.4-A RAMPING THE CL HEEL
Fig.5 PATTERN FOR THE CONCAVING TEMPLATES
STEP 4- CONCAVING THE RAMP
The flat ramps are now hollowed into an in-curved shape by scooping them with the chisel (see Fig.6 or 6-A). (Steel-string only: mark the end grain surface using the template with flat side held against tenon.) The chisel (skew) is held flat side up and belly side against the wood. Note that lifting the handle while pushing up the ramp causes the chisel to dig in and take a deeper bite. Lowering the handle will allow the chisel to scoop a thinner shaving. Adjust the handle height as necessary to remove smooth, even-sized shaving curls producing a hollowed curve. Do not proceed until both cheeks of the heel are carved to a similar curve.
FIG.6 CONCAVING THE RAMPS (SS)
FIG.6-A CONCAVING THE RAMPS (CL)
STEP 5 - CARVING THE PRIMARY FACET
We now begin the initial step in carving a graceful transition between the horizontal shaft and the vertical heel. A large facet is cut starting at the heel-cap outline, traveling up the heel, swooping around and into the shaft as shown in Fig.7 and 7-A.
The smoothness and continuity of this facet cut will determine in great measure the final appearance of the finished heel. Take care to remove material with light, full-length strokes, rather than short gouges. The student must strive to remove progressively only as much material with each pass as will leave a smooth surface for the next pass, lest the curved facet become a random, lumpy form. (If lumps or creases occur, you may fall back on the wood rasp to even out the lumpy surface before proceeding to make the next, deeper facet cuts with the chisel.)
The chisel is held belly down, as we have said, except to make the initial entry cuts into the heel at the heel-cap area; here it is pushed flat side down into the facet for an inch or so into the heel, then flipped over onto its belly to carry the facet around toward the shaft. (Classical only)
If the chisel exits prematurely or pops out during the stroke as you travel around the curve, try to re-enter the cut where you left off (and just as deeply), always with the purpose of leaving behind a smooth sweep for the next, deeper facet cut. If you chronically stop the chisel midstroke in the same spots along its travel, a nasty crease will develop that will interrupt the smooth transition and will be difficult to remove. If you must stop along the facet stroke, stop in a different spot each time.
Duplicate the major facet on the other side of the heel. Do not proceed until both are as similar and symmetrical as possible.
FIG.7 CARVING THE PRIMARY FACET (SS)
FIG.7-A CARVING THE PRIMARY FACET (CL)
STEP 6 - CARVING THE SECONDARY FACETS
The primary facet is now broken into smaller, or secondary, facets as the heel approaches its final contour (Fig.8 and Fig.8-A). From here on be sensitive to grain direction, particularly at the shaft. If tearing or splitting begins as you enter the shaft, reverse the direction of the chisel cut.
FIG.8 CARVING THE SECONDARY FACETS (SS)
FIG.8-A CARVING THE SECONDARY FACETS (CL)
STEP 7-REFINING THE CARVED HEEL
Examine Fig.9 and 9-A. All lumps, creases, and facet lines must be shaved away with the skew knife, and finally with a finely burred scraper. Work the heel surfaces to a sharp crease down the centerline with the scraper, working the crease until it is straight and sharp for most of its length. Remove all tool marks with #120-grit garnet sandpaper.
FIG. 9 HEEL REFINED WITH SCRAPER (SS)
FIG.9-A HEEL REFINED WITH SCRAPER (CL)
William Cumpiano worked as a professional furniture designer in the late sixties in New York City when he met Michael Gurian. After a brief tutorial with him, he elected to pursue the trade of guitarmaking, starting as an employee of Gurian Guitars, Ltd., in New Hampshire and later as a partner to Luthier Michael Millard. He opened his own studio, Stringfellow, in 1974 and has since established a reputation for individually handcrafting fine guitars for professional musicians across the country. He has written numerous articles, which have appeared in various trade and technical journals such as Frets Magazine, Fine Woodworking, Journal of Guitar Acoustics, and the Quarterly of the Guild of American Luthiers. His shop is currently located in Hadley, Mass.
Jonathan Natelson is an accomplished guitarmaker who currently practices law in Philadelphia.
(Ed. note: This excerpt was taken from the galleys of the book, Guitarmaking: Tradition and Technology, prior to it's publication; the photographs that accompany the text were not available as we went to press with this catalog. In certain instances where the text may not have been clear without the photographs we have added a few words to clarify, and we have deleted the references to the photographs.)
Text From The Luthiers' Mercantile Catalog - 1993
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