Tuesday, February 18, 2014

Fretboard Binding

Gluing the purfling to the binding before it's attached to the fretboard edge seemed to be the most logical approach when I began binding my fretboards, but I found it a challenge to accurately align the lower edge of the purfling with the underside of the board, no matter how careful I was when gluing and clamping it in place.

I managed to achieve acceptable results on the first couple of bound fretboards, but was uncomfortable with the process and felt there must be a better way. After dwelling on the problem off and on for a while, it occurred to me that I could just glue the binding on first - sans purfling - without fussing too much about aligning its lower edge exactly.

To solve the problem, I've knocked together what could best be described as a mini router table. With my laminate trimmer clamped in position from below, and a makeshift fence in place, I make some test cuts on scrap, adjusting the trimmer so that the rebate cut by the router bit will be the exact depth of the purfling strip. The width of the rebate isn't quite as critical, as long as it's less than or equal to the width of the purfling - any overhang can be trimmed off later.

Having set up the trimmer and fence, it's a simple matter of running the bound fretboard along the fence to accurately form the rebate for the purfling. The curved sections at the soundhole end of the board deserve some special treatment, but they're easily addressed using a similar approach.

All that remains is to glue the purfling strips into the rebate, with help from the same clamps used to glue kerfed linings strips in place. The purfling at the soundhole end of the fretboard is mitred to achieve a neat look.

I'm sure there are other equally effective methods, but this one works for me!


Fingerboard Inlay

I think it's a commonly held view that for the majority of players, traditional fretboard markers provide little practical benefit (the markers on the fretboard edge are a different story), but I can't quite bring myself to leave the fingerboard totally devoid of decoration. Having said that, my ambitions where inlays are concerned are modest indeed, and while there's no denying the skill and sheer artistry displayed by the likes of Larry RobinsonGrit Laskin and Jimmi Wingert, I have no desire to emulate them - even if I thought I had the ability and temperament to do so.

The abalone and pearl inlay I've come to regard as my own was originally inspired by the decorative elements found on Bob Benedetto's arch-top guitars, but has evolved over time to the extent that my conscience is now clear - I no longer view it as imitation. I'm not adept at distilling design ideas down to abstract representations - I'd fail miserably at logo design, for instance - so whatever I dream up tends to be fairly representational. Where my fretboard inlay is concerned, I've stretched those personal limitations ever so slightly, but it's still blindingly obvious that the inlay represents a single flower flanked by two leaves.

I draw the shapes freehand, directly onto the pearl and abalone blanks, then cut the pieces out with a jeweler's saw. I don't feel the need to be terribly careful as I cut, knowing that the shapes of the individual pieces lend themselves to clean-up and refinement on my spindle sander. I'm quite happy for the exact shape to vary from guitar to guitar; given that I strive for accuracy and consistency where every other aspect of the guitar is concerned, it's nice to introduce some elements that have come into being by a more organic process.

My Dremel has its shortcomings and limitations, but it's an appropriate tool with which to route the inlay cavities. I need to keep the cavities free of wood dust as I proceed, and the solution is provided by an aquarium pump running alongside me on the bench. The outlet hoses from the pump are taped to one of the pillars on the Dremel base, and direct a constant stream of air onto the work. They disperse the ebony dust as soon as it's produced, which helps maintain a clear view of the lines I've previously scribed around the individual inlay pieces.

Using tiny spiral downcut router bits, I can cut accurately up to the lines, with a scalpel blade and my smallest chisel tidying up the corners that were too tight for the router bit to deal with. The inlay experts would have me believe that it's prudent to undercut the edges of the inlay cavities with a ball-end bit, but my inlay is so simple, and my results to date of a decent enough standard, that I haven't found it necessary to explore that option. If I've been careful enough, any gaps between the inlay and the walls of the routed cavity are insignificant. Those that are evident are easily hidden with matching wood dust and a drop or two of thin cyanoacrylate (CA) glue applied after the shell pieces have been glued in place. Of course, it helps that ebony is very forgiving in this regard!


Wednesday, February 5, 2014

A Guitar-Shaped Box!

Hey, this is beginning to look like a guitar!


Saturday, February 1, 2014

Fitting the Back

Perhaps there's some aspect of successfully fitting the back that represents a significant milestone along the way to completing a guitar, or maybe it's just that I've repeated this part of the process enough times that I feel confident in the outcome and have come to enjoy the sensation and sound of the back braces clicking neatly into their pockets. Whatever the reason, it's a part of the build process I look forward to and derive great satisfaction from.

To reach this milestone - assuming that the dome of the back has already been sanded into the rims - I carefully align the back with the centres of the head and tail blocks, then mark the sides where the brace closest the the tail block will intersect them. I lay a steel rule across the guitar to join the corresponding marks, and pencil the line of the braces onto the top surface of the linings. 

As a precaution against chipping, I make a saw cut equal in depth to that of the brace end on the side of the pocket likely to be chipped by the clockwise rotation of the bit. I hope the right-hand photograph below shows this clearly.

With a spiral downcut bit mounted in the Dremel and carefully adjusted for depth, I rout the first pair of brace pockets, using the pencil lines as a guide. If the marks were placed accurately, the braces slip into place with just a hint of resistance. I check the fit of the back and widen the appropriate brace pocket to compensate for any misalignment. Once I'm happy with the fit and alignment, I can mark the next pair of brace pockets, confident that the alignment of the back will be more securely and accurately established as I proceed. When the four pairs of brace pockets have been prepared and the back fits perfectly, I can allow myself a moment of self-congratulation - before I remind myself that it's really only a minor triumph and that there's plenty of work ahead of me!