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Week 11: May 29 - June 3

 

These are the three elements of the binding/purfling that I'm using. The two photos show the top view and side view of the same three strips. The strip on the left is the same black-white-black wooden strip that was used as part of the rosette. It's the narrow purfling used on the back of the guitar. The center is the herringbone strip that's used as purfling on the soundboard and the strip on the right is rosewood with a thin line of maple or holly or some other white wood. This last is used as binding on both the soundboard and back. The scale is marked in 1/32" increments

LMI recommends bending the herringbone dry, and it bends quite readily, possibly because the heat makes the glue let go a little and allows all the components to slide around against each other slightly. The b-w-b also bends without a problem, but the binding strip was a real pain. I bent the strips for the back dry, and had some cracks where there was short grain in the strip; I was quite surprised to find that is wasn't straight-grained like everything else supplied in the box, but took it as a lesson and went on more carefully, soaking the binding strips before bending them for the face. Though I was able to push the binding flush everywhere in a dry run, I got gaps in several places on the back between the binding and purfling. I could not see these gaps while taping the glued binding down, but there they were when I lifted the tape. This was the most unsatisfactory part of the process so far.  As I mentioned on an earlier page, I hope to be able to fill these gaps with burn-in lacquer stick. 

There is a slight variation in the depth of the rout, due at least in part to the slight arching of the soundboard. In addition, the depth of the purfling ledge is deliberately limited to keep at least 1/32" of the soundboard under it in contact with the linings inside the box. Together these factors mean that the purfling and binding will stand a bit proud of the side and top and will need to be scraped down. As attentive readers will have noticed, I don't mind using a scraper; in fact I get a kick out of it. I spent a happy hour or so scraping the bindings down to what you see in this photo.

I have been eager to get to this next step, making the fingerboard. It's a real milestone. Once this is done, only the bridge remains as a major part that's not at least shaped and recognizable. Here's the setup for marking the fret locations. Readers over forty will appreciate the headband magnifier, for reading the half-millimeter scale. The ebony blank is flattened and thinned to 7/32" and the nut end is flat and square to the edges. A block of wood is clamped to a plank to act as an end stop, and the fingerboard blank is butted up against it. A ruler marked in half-millimeters is also butted up to the stop and clamped down on the fingerboard blank. The plans with the list of fret distances is handy, and so is a can of caffeine-free diet Pepsi (you don't want shaky hands or a sugar high).

A knife is used to mark each fret position. This is just a nick, and will be gone over with a square to make a clear cut mark across the board.

Here I've marked the fret at 158.6616 mm from the nut. Just kidding. I aim for the nearest quarter of a millimeter, since my scale is marked in half-millimeters. Just a little nick with the knife at this point, and then take away the scale and use the engineer's square to mark a fairly heavy knife cut straight across the fretboard at each nick. 

This fretting saw came from Stewart MacDonald. I've adjusted the side rider to the depth I want the slots plus the thickness of the blade of the engineer's square, so it stops cutting downward when the slot is 1/8" deep. 

I had a good deal of trouble with the saw binding in the slot while cutting these. There is little or no set on this saw (the teeth of a saw are are "set" by bending them to alternate sides of the blade to make the cut a little wider than the thickness of the saw, to prevent binding). I smeared a little Butcher's wax on the teeth of the saw, which helped, but it had to be renewed after cutting every second fret. In one instance, the saw bound in the slot, then bounded out of it, putting a deep gouge in the surface of the fretboard.

Here the slotted board is ready for gluing. The rest of this page has few photos for a lot of work, because I got into the work and neglected to take them. In addition, many of the steps involve subtle changes in the contour of the surface of the fingerboard, something it's a little difficult to get good pictures of! I'll do my best to describe in words what's missing in the pics. After slotting for the frets, the shape of the fingerboard is laid out on the fretboard blank and the blank is cut down close to the line with the bandsaw and then trimmed to shape with a plane. 

C&N say to cut slots for twenty frets and then cut off the fingerboard just past where the twenty-first fret would go. Since I'm using a different plan than they are,  I was wary of blindly following this. I decided to cut the twenty frets and get the thing glued to the neck and test-fitted to the box before deciding where to cut it off. Besides, I thought I might want to try some kind of treatment at the end of the fretboard. Stay tuned. 

Here the trimmed fretboard is being glued to the neck. The thick caul on top is 3/4" plywood. It's intended to insure that uneven clamping pressure doesn't introduce a curve into the assembly.

This block is clamped to the tenon to provide support for the overhanging part of the fretboard during the fretboard radiusing and fretting operations. Here's where the photos get pretty thin. For a better description than I can craft, see Cumpiano & Natelson. In brief, the fingerboard top is shaped so that a smooth curve that results in a difference of about 1/16th" between the sides and the crown is planed in all along the fingerboard. Because the fingerboard is wider at the body end than at the nut end, this results in the shape of part of the surface of a cone, with the fingerboard running straight under each string. C&N recommend final sanding after the frets are installed for beginners, but say they final-sand first, and are careful when installing and shaping the frets. So I say what the heck, I'll sand down to 320 grit before the frets go in, and if I screw up I can always re-sand. 

Installing the frets goes smoothly -- again, not much to photograph about this process. Frets come in a four-foot length of t-shaped wire, and you can cut off a piece and gently tap the lower part of the T into the fret slot. Or, you can hold the end of the wire to the slot and tap it in, and then cut it off. After fumbling around with the first process for a while I settled on the second. You cut it with a strong pair of wire-cutting pliers -- it's pretty thick and it takes a good strong squeeze.

After all the frets are installed, the cut ends are hanging over the edge, and they need to be filed flush to the side of the fingerboard. If you trimmed the side of the neck blank right down to the line before this, you've made a mistake -- the file rides nicely on this overhang while staying vertical to eat away the fret ends flush to the ebony. When the ends are flush, the file is tilted and run along the ends of the frets to put a 30-degree angle on the ends of the fret beads (the bead being the visible part of the installed fret wire, while the tang is the part inside the slot). 

As you can see here, I've cut off the end of the fingerboard a little generously; I'm still deciding what to do with the end.

I am tremendously psyched by the end of today's work I swear I eat up more time sticking the neck back on the box for photo-ops than I do building. Not quite true, but what the heck. It helps morale to sit back and see the progress you've made. 

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Copyright 2001 Stephen Miklos