Finish Neck and Fretboard Wednesday, January 16, :36 PM

Transcription

1 ASL Breakdown Page 1 Finish Neck and Fretboard Wednesday, January 16, :36 PM Layer on the fret board, making sure registration pins are in place and everything lays flat. The 3/16" aluminum nutsurrogate rod must be in place during this step.

2 ASL Breakdown Page 2 Fret board clamping: the neck is up on stands with a hard plastic caul underneath for protection. The neck and fret board (remember the registration pins!) come next. This is followed by another plastic caul that has been hollowed out so the pressure is applied at the edges of the fret board. This is all topped with a heavy steel beam with sandpaper affixed to the top for a good grip. Four small bar clamps, evenly spaced, hold the neck and fret board together. A single larger bar clamp clamps from under the heel block. Bar clamps have some spring to them, so that as glue oozes out, the clamp continues to apply pressure. Fretboard gluing cauls Whole affair from underneath. Longitudinal view. After gluing and clamping, remove the nut-surrogate bar and use Q-tips to draw the epoxy out of the nut channel. When it is basically cleaned out, use alcohol with more Q-tips to finish cleaning out the channel.

3 ASL Breakdown Page 3 Trimming the neck that is proud of the (tapered) fretboard. Leave some overhang. Trimmed - the heel block prevents trimming the entire length of the neck. The remaining tab is easily chiseled.

4 ASL Breakdown Page 4 Rasping the overhang left by the bandsaw. Be sure to angle the rasp slightly away from the fretboard so as not to scratch it. When the rasp begins to take away the glue line between the neck and fretboard, switch to the smalltoothed side and/ or sand the remainder with #80 and the large block. The ebony fretboard must remain intact and square to the plane of the neck until the neck is shaped. One side of the neck trimmed to the fretboard. Detail of above.

5 ASL Breakdown Page 5 Charles making templates for the neck contour. The neck is contoured by rasping arcs at both the 1st and 10th frets. Those arcs are given by the 2 sides of the template. The salient measurements are the fretboard width at those spots and the depth of the neck (not including the fretboard). The arc of a circle is drawn between these 3 points, giving the neck profile at those 2 neck positions. I had to make a custom profile because of the shallowness of my neck. The contour template will be checked frequently when carving the neck. What to do if you don't want a circular neck profile? Neck laid out for initial shaping. Pencil in a thick line at the middle of the neck. This is territory to avoid when using the rasps.

6 ASL Breakdown Page 6 Initial rasp cuts at the 1st fret. Use the rounded rasp. Check frequently with the template and carve little by little at the points where the template encounters fresh wood. Cutting is done when the cut is symmetrical and the template fits over it with little or no light showing between neck and template. Checking cut with tri-square. The neck between frets 1 and 10 is carved by making successive cuts at an angle to an existing cut, which makes closer and closer approximations to a conical section the ends of which have radii corresponding to the arcs from the original template. When the rasp becomes too course an instrument for smoothing the remaining surfaces, switch to sand paper - first on the large block and then hand-held. Neck carving template Checking with the template.

7 Once the 1st and 10th fret arcs are carved, the idea is to connect the curves smoothly. Begin carving between them on about a 45-degree angle using the flat rasp. Check frequently to make sure the depth of this cut yields two more or less parallel lines describing the new plane of this cut. In other words, the cut is the same width down the length of the neck. Check for lumps and high spots using the tri-square. ASL Breakdown Page 7

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9 ASL Breakdown Page 9 Preparing to carve the heel: draw center lines across the heel cap and down onto the front face. Use the triangle to locate the center of the heel block based on the location of the truss rod.

10 ASL Breakdown Page 10 Sketch in a heel cap contour from a point at the front to the back corners. Begin carving from the heel cap to the neck as contoured at the 10th fret. Make the cut as steep as possible by using the flat end of the rasp as long as possible. When the heel contour is too curved, switch to the curved side of the rasp (this side eats wood quicker). Also a plane or sanding block may be used here. Carve the block one half at a time. Try to match the second half to the first as symmetrically as possible. Carve as vertically down the face of the heel as possible.

11 ASL Breakdown Page 11 Still lots of material left on the side of this heel. Remember the scraper makes a great carving tool. Use caution as you approach the neck as the rasp can gouge areas that are already close to final shape. Use double layers of luthier tape to protect the neck while carving the heel in this area.

12 ASL Breakdown Page 12 First half of the heel is carved now match it! Note that you should avoid the last 1/4" of each side of the heel block near where the heel joins the body. The line from the fretboard to the bottom of the heal should be straight in this area. When rasping is done, get out the scraper. This is also a great carving tool and can remove a lot of material with good control.

13 ASL Breakdown Page 13 The first step in carving the peghead is to trace the peghead outline from the template onto the top face of the peghead. Then use the spindle sander (3" spindle) to follow the traced curve. Note that the neck is held up on a block and the bottom of the neck is defining the plane of attack with respect to the sander. This gives a contour line to this area that is not vertical with respect to the peghead. Next, sketch out the curve between the side of the peghead and center of the neck at the nut. Start carving with a standard toothed rounded rasp using the centerline, traced curve on the back of the peghead, and established arc of the neck at fret 1 as references. Try to carve a steep angle from the back of the peghead near the 1st and 6th tuners down to the ebony peghead cover. Be sure to keep clear of the ebony.

14 ASL Breakdown Page 14 As with the heel, use the scraper for final detailed carving. Here, the scraper is run backward from the carved neck to the peghead area using light pressure. This smooths the transition between the 1st fret curve carved earlier and the new peghead contour. Light pressure on the scraper allows it to ride over the ridge between these 2 areas are remove a small amount of material with each stroke. Finished peghead carving. Note symmetry visible at the neck/peghead glue joint. Finally, sand the neck to the level of the fretboard without removing any ebony. The plate sitting on top of the heel block is a large sanding block. It was used to finish rounding of the neck after the bas ic shape was established with the rasp and scraper. Here, it is used to create a level plane between the fretboard edge and the bottom of the heel block. Light pressure should be all that is needed at this point - the block itself should be heavy enough for this pressure.

15 ASL Breakdown Page 15 Drilling the recess channels for the tuning pegs. The fixture should look familiar. Be sure to support the peghead as much as possible and don't let the neck ride up on the support fixture. Attach the tuning machines. Make sure they are all in line on each side - note use of straightedge. The special hole punch tool (foreground) fits into the tuning machine screw hole and precisely centers a small punch at the center of the hole, which can then be drilled to depth.