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Douglas Harrison is one of the most talented archtop builders today. His instruments are played by some of Canada's most respected jazz guitarists and his backorder list is getting longer and longer! Mr. Harrison has been gracious enough
to supply me with some images of his construction process. I always
find it fascinating to see some of the different stages during the fabrication
of a musical instrument. These photos don't really come close to
telling the whole story, but they do give a bit of an insight into
the world of lutherie!
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| Squeeze clamps are used to glue the kerfed lining on the frame. Note the tensioning sticks that hold the sides to the shape of the mold to achieve good symmetry. The internal lining adds more gluing surface for the top an back and takes into consideration the slots that will be routed to accept the outer binding and purfling. Kerfing or slotting the lining allows it to conform to the curves of the sides without having to heat and bend them. Note the substantial mahogany head block that will eventually accept the dovetail of the neck. |
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| Carving, graduating and
tuning the top is definitely the most critical operation with regards to
determining the final tone and projection of the instrument.
Douglas Harrison hand carves both his top and back plates to achieve the
maximum control.
A seasoned luthier like Harrison controls and shapes his sound in many ways. High round arched tops sound quite different than ones that quickly reach a plateau and then maintain a flatter profile. Thick tops with tone bars offer different properties than thinner X-braced tops. Some builders tap tune their top & back plates to specific frequencies while others keep shaving the outer recurve until the instrument 'comes alive' to their touch. This is where science meets voodoo and makes or breaks an instrument!!! |
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| Vibrations on top plates find
less resistance traveling with the grain and more resistance against.
The idea of adding struts (apart from structural considerations) and thinning
the top toward its edges, is to help efficiently utilize the full
width of the top.
This photo shows Douglas fitting the X-brace to the underside of the carved top. You can imagine the skill & patience needed to shape the underside of each brace to conform to the complex curves!!! This is very time consuming to say the least! In this shot the f-holes (or maybe s-holes in this case) have been cut. The size, shape and positioning of these ports all have an effect on the sound. You can make minor adjustments to the air tuning (Helmholtz resonance) by adjusting the size of these apertures. |
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| Here's a shot of the
'frame' after the back has been glued on. The vertical pieces glued
to the sides are to strengthen and prevent distortion over time.
This particular instrument has Douglas Harrison's own louvered side port design. The side port throws more sound up at the player without seeming to alter the frontal projection of the instrument. Creating a side port in this manner is much more time consuming to achieve but looks fantastic. Not only are these louvers very delicate to cut out, but Harrison then finishes each hole off by gluing decorative binding on the inside of each aperture!!! Note the extra piece of wood glued to the frame on the lower bass bout. This will eventually be used in creating the 'Laskin Armrest', a beveled area on the perimeter of the top. |
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| Here's the top being glued to the frame. Bar clamps, cam-actuated clamps and wood wedges all ensure a strong joint without applying undue tension on the top plate. You apply enough glue so that the joint is not 'starved' but not so much that it drips down the sides. After the top is glued on an archtop you can't get back in to clean things up! |
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| This shot shows the female section
of the dovetail joint. The dovetail joint often baffles beginner
guitar builders, but once you get used to it, it is elegantly
simple and structurally sound.
Note also the two tiered edge routes that are ready for receiving the multi-purfling strips. Body binding and purfling seals end grain, adds visual interest and protects the heaviest wear areas of the instrument. When the binding is wood, it has to be heated and bent before being 'roped' on. Plastic binding is flexible enough to just be taped in place after the glue is applied. |
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| Tough fiber tape is utilized to hold the tightly radiused cutaway binding in place. Notice the precision mitered joinery of the thin purfling strips in the bottom center of this picture! |
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| This is one of my favorite
stages of the guitar making process. This is the box 'in the white'.
The woodworking is complete and the instrument has been prepped for finishing!
This shot shows Doug Harrison's louvered side port, 'Laskin Armrest' and a custom abalone top perimeter. The bound S-holes are definitely a nice touch too! Harrison actually strings up his instruments before applying the finish so that he can make any last minute adjustments to the carving of the top. It is this kind of attention to detail that produces ultra resonant instruments with more sonic nuances than production guitars. |
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| This is a great close-up of the male
part of the neck dovetail as well as the suspended fingerboard extension.
Suspending the fingerboard 'tag' allows more of the top to vibrate and
allows neck angle movement without affecting trueness of the fingerboard.
Note the recess cut on the side and end of the fingerboard to accept the neck binding. A bound fingerboard is much more time consuming but tidies up the look by concealing the fret tangs. |
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| At this stage, the truss
rod has been inserted and the fingerboard is being glued on.
Introduction of water-based glue at this stage can back bow the neck.
To prevent this, Harrison uses a milled aluminum bar to keep the
neck & fingerboard assembly true.
Doug fabricates his own truss rod and it is one of the smoothest in the business. Jazz players use everything from .010-.046 to .013-.056 gauge strings and the Harrison truss rod accommodates this wide range of tension. |
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| Talk about a complicated binding job! You have no idea how difficult it is to execute a four-layer bound headstock in this kind of complex peghead shape! There are not a lot of luthiers I know who could pull this off with flawless joints and flowing lines. |
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| Harrison applies his stain directly to the wood to help bring out figure in the premium Big Leaf maple back & sides. This accentuates the flame but also makes a microscopically thin nitro lacquer look a mile deep! One of the most difficult aspects of guitar building is the finishing and Doug Harrison is one of the best I've ever seen! |
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