Erik's Hjørne: INSTALLING THE CENTRAL ROSETTE MOTIF

Over the weekend Installed the rosette tiles for the central rosette motif. This proved to be a bit more troublesome than it needed to be.

I made a little miter box of some scrap of cherry I had lying about and then started cutting the tiles. I had put a little stop inside that miter box to get the tiles at an even thickness - 2mm. I numbered each tiles to facilitate installing them in a consecutive order. This jig was also used for the border motif, which were cut in the same manner, though only to thickness of 1.2mm.

All the tiles were place in a mock up rosette channel I had routed in some construction grade pine scrap using my little Dremel tool fitted with StewMac's 1/8" solid carbide spiral downcut bit and their precision router base and circle cutter - a setup I found really nice to work with. The cuts were clean and precise. This little mock up not only allowed me to test the circle cutter but it also to try the fit of the tiles and make some final adjustments to the tile log - planing an ever so slightly larger taper into it.

Then I set out to plane the soundboard to an even thickness of 3.5mm with my smoothing plane. I didn't alternate with a regular and a toothed blades as Cumpiano suggest, neither did I follow his scheme of planing along, diagonal and across the grain, but resorted to just planing along the grain working my way slowly from one side to the other with slightly overlapping strokes, and it seemed to do the trick. I measured often and planed areas selectively as needed if things got a little out of line.

As I reached the targeted thickness a hidden knot emerged near the center seam, but I hope it will disappear, or at least diminish, once the soundboard is plane to final thickness. Furthermore, I was able to arrange the outline of the guitar so that it will be hidden by the bridge patch and thus not impair the structural integrity of the top.

The outline of the body was drawn on the soundboard using the template and sawed out on my bandsaw leaving about 1/2" of waste. The position of the soundhole was also marked and a 3/16" hole was drilled for the circle cutter's center pin. Likewise a hole was cut in a piece of 3/4" MDF I used for support.

Like the mock up, the channel for the central motif was done with my little Dremel tool to a depth of 1.5mm but it was here things started to go a little haywire. As the channel for the central motif was about 15mm wide, it had to be routed in consecutive steps. By the time I started the second circle I noticed that it was a bit deeper than the first. I attributed it to the fact that the router base was riding on top of dust accumulated during the routing. So I continued vacuuming carefully during the process. By the third round the cut was still deeper and it became apparent that something else was wrong and I found that the depth adjustment screws had come loose and was slowly lowering the tool as I was progressing. Luckily it was only gone down 0.1mm, but still. I reset the depth to 1.6 mm stared over again this time making sure everything was nice and tight. As I approached the edges I dry fitted a few tiles and continued to widen the channel until the tiles butted up against each other in a nice and snug fit.

All the tiles were laid out in order ready to go, and a clamping caul and wax paper was cut. Everything was ready to go. It was getting close to dinner time and instead of leaving it until later I rushed ahead and filled the channel all the way around with glue and started to press the tiles in. For some strange and unknown reason I started on the side instead of the top, where the rosette will be covered by the fingerboard. I got a third of the way through when this suddenly dawned upon me and I quickly had to get all the tiles out again which proved to be quite tricky as most of them had started to set. In the end I was able to get most of the first ones out, and hereby moving the 'seam' between start and finish to somewhere under the finger board. I put in the rest, clamped them down and went into dinner only to find that half an hour later the glue had dried to a hardness that made it difficult to clean up. I don't know what I was thinking but thinking I wasn't. I cleaned up the glue the best I could and took a break and got my sons to bed and it was good to refresh my head.

Once to boys were in bed and the dusk of the evening was settling, I got to do what proved to be a very rewarding task - planing the tiles flush to the soundboard. Shaving the thin slivers of end grain, patterned in all their glory, was a very gratifying experience and a very welcome change from the panic and despair a few hours earlier.

CUTTING TILES