Custom Dreadnought Guitar #58 175


(click any of the thumbnails for a higher-resolution photo)

This bluegrass guitar is my first outing with "cooked" (Torrefied) wood. The red spruce top is mated with East Indian rosewood back and sides. Though this instrument is all about sound, it also has some very nice custom touches as well: Waverly tuning machines, curly maple bindings, and herringbone rosette and purfling. The unstained top looks well aged, and the entire instrument has an aura of a fine old warrior.

Did I mention sound? This one is finished just in time for the season's first bluegrass festival. I'll try to get some sound clips to share with you.

Construction Photos

The project begins with the joining of the top and back plates with hot hide glue. A quartersawn mahogany neck blank is cut for the headstock joint, and the neck heel is glued together. A neck block is cut and glued together. Fly cutters are used to cut recesses for the rosette.

The rosette lines are first dry fitted, then glued in with hot hide glue. When the glue is dry, the rosette is scraped level with the surrounding wood. I'm not familiar with the Torrefied (temperature modified) wood, and there is conflicting information on the Internet: some sources say the wood is more stiff, while others claim less. To find out for certain, I test a piece of the Torrefied wood against a same-sized sample of red spruce of which I'm familiar with. When the deflection under weight is measured, I find that the Torrefied wood deflects nearly 40% more than the untreated sample. What this doesn't tell me is how much thicker I need to make this top. To ascertain that, I gradually reduce the thickness of the untreated sample until the deflection is the same, then measure the ratio between the two. The result: I need to make the Torrefied top 3.4% thicker than my normal untreated tops, or roughly .005". Not so drastic after all. The top, back, and sides are sanded to finished thickness.

The sides are cut to profile, slightly dampened, and placed in a sandwich of paper, stainless steel slats, and heat blanket. The sandwich is placed in the bending jig and the sides are heated and pulled into shape.

The adjustable external form is set to dreadnought size, and when the sides have cooled they're removed from the bending jig and placed in the form. The truss rod slot is routed in the neck block and neck. The neck and tail blocks are glued to the sides. Kerfed mahogany lining is glued in place. Thin rosewood reinforcing strips are glued in full width of the sides, then a thinned section of lining is glued in overtop of the strip.

The purpose of these strips is not to make the sides stronger or stiffer, but to prevent the sides from cracking. The back plate is cut to shape. The top is cut to shape, and the bridge plate, soundhole bracing, and popsicle bracing are glued in. The upper side of the kerfed lining is glued in place.

The back's center-web reinforcing is glued in place. The x-bracing is joined at the center and recessed to receive the bridge plate. The bracing is partially shaped on the spindle sander, then glued into place with hot hide glue. The back center web is notched to receive the b ack bracing.

The back bracing is glued in place. The sides are temporarily removed from the form. A jig is affixed to the butt end, and the end graft is routed. A maple end graft is fashioned and glued into place. The end blocks are cut down to the width of the adjacent lining. The top and back edges are sanded to the same radii as the finished plates. The plates are tuned by carefully shaving the bracing while tapping and listening. I'm not looking for a particular tone, but a lot of musical notes with no dead spots.

The bracing locations are marked onto the sides, and notches are routed to receive the bracing. Hot hide glue is applied to the mating surfaces and allowed to dry. The parts are clamped together, and the glue is reactivated with a fine jet of steam.

The instrument is removed from the external form, and the edges of the plates are routed flush with the sides. To increase resonance and responsiveness, the top is thinned around the edge with a random-orbit sander. The body is routed to receive maple binding and herringbone purfling, and the binding and purfling are glued in with hot hide glue. The neck blank is cut to profile.

This specialized device allows me to perfectly align the neck and body in all planes, then cut the dovetail joint without resetting the jig. The neck heel is sanded to shape. The resulting dovetail joint needs almost no hand work for a perfect fit.

The tortoise heel cap is glued to the neck heel. The headstock is cut to shape. The headstock end of the neck is shaped in preparation to joining to the peghead. The headstock and neck are glued together. An ebony fretboard blank is sanded to a 16" radius, and fret slots are cut.

The fretboard is cut to finished dimensions. Matching recesses are cut in neck and fretboard to receive reinforcing bars. A rosewood overlay is glued to the peghead. Mother of pearl position markers are installed. Frets are set in a thin line of hot hide glue and pressed into place.

Side position markers are installed. Carbon-fiber reinforcing bars are glued into the slots previously cut in the back of the fretboard. The "Skipper" logo is cut from mother of pearl, recessed into the rosewood, and set in a mixture of ebony and rosewood dust. The overlay is trimmed flush with the peghead, and the inlay is sanded level with the surrounding wood.

The neck is shaped with planes, chisels, rasps and sandpaper. Holes are drilled for tuning machines and bushings. The body bindings are scraped level with the surrounding surfaces, and the instrument is thoroughly sanded.

Channels for the reinforcing bars and truss rod are extended into the guitar's body. The fretboard is glued to the neck. The bridge is located, and the areas to remain unfinished under the fretboard and bridge are masked off. The neck is darkened with a dilute solution of dichromate. The instrument is given a coat of vinyl sealer. After the sealer is thoroughly dried, the pores are filled with a water-based material.

Sanding between applications, the process is repeated until the surface is level. The instrument is given another coat of sealer, then allowed to dry overnight. Two series of three coats each of nitrocellulose lacquer are applied, with an hour between coats and a day between series. Then the instrument is sanded perfectly level and two additional coats of lacquer are applied. Then the instrument is allowed to cure for 10 days to 2 weeks before final buffing and setup. When the lacquer has cured, the instrument is wet-sanded with increasingly finer grits of MicroMesh paper. Tuning machines are installed.

The neck is glued to the body. The final shaping is completed on the bridge, and it's glued to the top. Bone nut and saddle are shaped and fitted, and a pickguard is installed. With some strings and some setup, this one is ready to go to work.

Thanks for watching this project

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