Up next is the headblock – the mortise inside the guitar that accepts the neck tenon. From a solid piece of Mahogany, I used the table saw to hollow out the mortise where the bolt-on neck attaches. I am careful to remove just enough wood to achieve a tight fit (but with just enough allowance for wood expansion). Two holes are drilled through the mortise where the bolts will attach to the barrel connector in the neck.
Using the Delta table saw to hollow out the mortise for the neck tenon
The real test is making sure the headblock and the neck fit together perfectly and the bolts fit through the holes all the way to the back of the neck where the barrel connectors are. This one is a perfect fit, probably because I measured four times before the first cut was made (can’t be too careful)!
Overhead view of the headblock attached to the neck.
The barrel connecting bolts through the headblock. Notice the trussrod emerging through the top.
The upper bout of the guitar is not as deep as the lower bout so there will be a 15 degree radius. This starts from the headblock – the depth of the headblock where it meets the neck is 3-1/2″. The other end of the headblock is 3-5/8″ so an angle cut must be made. I use the bandsaw for the rough cut and the disk sander for the fine sanding. Once the angle cut is made, it is time to fit it to the top in preparation for gluing.
Fitting the headblock on the top before gluing.
At this stage, the heel needs to be carved to a near-finish level. I have no power tools or jigs to assist with this process so I use very sharp Crown chisels, cabinetmaker rasps, and sandpaper. The heel contour is another luthier signature and I have built many different types. For Dan’s guitar, I believe that the short 12-fret neck would look best with a modest heel, similar to a Martin but more rounded and slightly less mass.
Beginning the carving process with a 5/8″ Crown chisel with a 30 degree bevel.
I use facets to carve the heel. I draw parallel lines and carve to the lines. To avoid the chisel from digging into the wood on the tight curves, I turn the chisel over and use an upstroke.
Reversing the chisel on the upstroke to cut to the contour of the heel.
I really enjoy this process because it is satisfying to create a beautiful shape from a block of Mahogany. The carving takes over an hour and I switch from my right hand to my left hand to avoid fatigue.
I have a short story about this process. When I was studying with George Morris in Vermont, we worked from 8:00 am to 11:00 pm. After a full week of this, I could barely move my right arm – it was spent due to the constant activity. When I informed George that I could not move my right arm, he looked at me rather suspiciously and said: “then use your left arm.” And use my left arm I did for the next several days. I have been using my left and right arms equally ever since and I thank George for that “encouragement!”
With the neck clamped firmly in my bench vise, I carefully chisel to the facet lines.
After the chiseling has removed the bulk, I move to a cabinetmakers rasp to complete the rough shape. A cabinetmakers rasp is used because it has random teeth patterns for quick and even removal of wood.
The basic heel shape after rasping.
The completed heel.
I finish the heel using 100 grit and moving to 150 grit sandpaper.
After the slots are routed and cleaned up with 150 grit sandpaper, I cut out the extra length at the top and sanded it even to the outline.
The completed headstock save the shaping of the bottom to meet the neck width.
Cutting out the rough shape of the heel on the bandsaw.
The next step involves the other end of the neck – the heel. I first draw the template of the heel shape and then cut it out with a bandsaw. The rough curve is then sanded smooth using the end of my combination disk/belt sander.
The Mother of Pearl logo is striking against the dark Ziricote.
Now that the Routen logo is inlayed and sanded even to the headstock Ziricote veneer, the tuner holes and slots need to be completed. I shaped the headstock to its final shape using the bandsaw and then a rasp and sanding block to even out the sides.
The Mother-of-Pearl Routen logo inlayed and sanded.
This is a creative shot of the logo through my magnifying glass.
I placed the headstock routing jig on the headstock. This awesome jig was developed by the Luthier Tool Company (www.luthiertool.com) and has guides for the tuner holes and slots where the strings will join the tuner. First I drill the tuner holes by placing the 1/4″ drill bit through the bushings and drilling 1-3/4″ into the head.
The slothead jig provides the capability for precision drilling and routing.
Slowly removing layers of wood within the slots using the router.
After the six tuner holes are drilled, I use the Laminate Trimmer to route the slots in the face of the headstock. This takes over an hour because I just remove about 1/8″ of the wood each pass. After each pass, I lower the router bit another 1/8″ until the slot is all the way through the headstock.
Shaping the top’s bracing is part art and part science. There is over 100 years of tradition in steel string bracing but most luthiers develop their own methods. Perhaps the majority of bracing used today is derived from CF Martin’s research and development. The bracing directly affects the tone of the guitar so needed attention should be given to this step in the building process.
I use very sharp chisels to shave wood from the braces. If the chisel is sharp enough, the wood should come off in curly scraps. It is very easy for the chisel to cut the top if it should veer from the brace so I take great care and use two hands to guide the chisel.
Carefully using the chisel to shave the brace.
The X bracing is shaped to have a point while the tone bars are more rounded. All the brace ends are sloped toward the top until they are even with it.
Carefully maneuvering the chisel to shape the brace and to avoid cutting into the top or a finger.
Once the initial chiseling is completed, I use 150 grit sandpaper to smooth the braces. Sitka Spruce bracing is very quick to sand so it requires very little pressure. Once the sanding is complete, it is time to determine if any further shaping is necessary to achieve the desired tone of the top.
The intial shaping of the braces is completed.
There are many “scientific” methods of testing the results of bracing including deflection testing and Chladni patterns. I prefer tap tone testing. This is where you use your ears to determine the pitch, sustain, and overtones of a top. I strive for a pitch between G and A.
This top is currently at A# and it has wonderful overtones but not enough sustain. I will gradually sand off some of the width of the X and finger braces but none of the height because the height of a brace contributes more to its stiffness than its width. The process is to spend five minutes in sanding followed by tap tone testing and this repeats until the top is at G# or A and has sustain of at least six seconds.
Dan has selected a small “Routen” logo made from Mother-of-Pearl. I have all my Pearl and Abalone inlay materials custom made by Andy DePaule in Oregon.
The Mother-of-Pearl logo against the Ziricote headstock.
To inlay the logo, it is necessary to route a channel in the headstock to accommodate the letters. The channel must be as close to the size of the logo as possible and deep enough so the logo is slightly proud of the Ziricote face veneer. This is very time-consuming because it requires precision.
I use a 1/32″ downcut router bit in my Dremel tool that is attached to a special base for fine routing. I have a pump and tube connected to the base to softly blow away the sawdust as I route. This helps keep the work area clear for precise routing. I have built a headstock jig to firmly seat the neck for routing.
I have a pdf template of the logo and I cut out the logo shape and glue it to the headstock. The position is centered and 3/8″ from the top.
The guitar neck clamped in the headstock routing jig.
The logo outline glued to the headstock. The “R” is coarsely routed.
Using the Dremel, base, and pump I slowly route the outline first slightly undersized and work inward with each letter. Once the initial route is completed, I use the actual logo to place in the channel. It is too large at first and I use a series of colored pencils to trace the shell on to the glued-on template and I route to the colored line.
It takes about three hours to complete the routing, sand off the logo template, and clean up the headstock before gluing.
Routing out the “R” by drawing the outline and routing just shy of the line.
Slowly routing the logo channel. If you ever need a task to help with patience, this is it!
After routing, the channel is cleaned of of all excess debris. I place a base of polyvinyl glue in the channel and carefully press in the shell logo. A piece of waxed paper is placed over the logo and I clamp a piece of plywood over it to press the logo even with the headstock. This is left to dry overnight.
After several hours of this process, my arms, eyes, and brain are tired!
Today the Waverly tuners were delivered. They have a beautiful gold finish with Ebony buttons.
Waverly steel string tuners for a slotted headstock.
Now back to the top. After drawing out the bracing patterns on the inside of the top, I cut out the outline of the top oversized by 1/2″. I use the 9″ bandsaw for this task and I do not have to be extremely careful at this stage but I use this step as practice for when I do the final cutout.
Carefully cutting out the outline of the top.Close-up of the cutting out process.
Bracing patterns are a luthier’s signature and perhaps the most important tone-shaping variable. The exact placement, height, width, material, strength and shape of the Spruce braces will impact the sound of the guitar. The top will have a slight dome for extra strength so I use a 25′ radius. This is accomplished by sanding an arc into the bottoms of each brace using a 25′ template.
This is a 25′ radius plexiglass template that I use to draw the arc on the brace bottom.
Spruce bracing cut to size, radiused on the bottom, and ready to glue.
I drill a 1/4″ hole into the center of the two transverse braces to accommodate the truss rod adjusting Allen wrench that may be needed for future neck adjustments. Transverse braces are the braces between the soundhole and neck.
This 12-fret to body design leaves more room between the soundhole and the neck joint so I am modifying my transverse bracing. I am using Mahogany for the lower transverse brace because it has greater mass than the Spruce. The upper transverse brace is oversized Spruce 5/16″ wide and 1/2″ tall.
I use a thin film of special luthier’s polyvinyl glue on the brace bottoms. To clamp the braces in place while they dry, I use a special “go deck” that I built that allows insertion of Ash “go bars” between the top of the deck and the top of the braces, exerting many pounds of downward pressure on the braces. I made “go bars” out of Ash because of their strength and bending ability. The Cedar top is placed in a 25′ radiused “bowl” so it conforms to the shape of the braces during gluing. After five minutes I clean up glue squeeze-out and let the top and braces set overnight.
Gluing the X bracing in the go deck.
Complete view of the go deck during brace gluing.
Next: back to the neck headstock to route in the Routen logo.