Rosette channel cut too small: how do I enlarge it?

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Rosette channel cut too small: how do I enlarge it?

Ken Whisler - 04:03am Feb 26, 1998
I am on my first classical guitar. Before I ask this question, maybe I should confess my error. I carved the channel by hand. My rossette was logged as a 3 ring, an 8 x 8 central motif with 2 outer 2 x 5 motifs, separated by veneer lines. My mistake was 2 fold; 1) did not allow wide enough channel for glue and 2) layed in 2 rings instead of all 3, so I did not realize mistake until going all the way around the soundhole. :o(((((((

Can I save this rosette and what is the best way to enlarge the channel? If I am going to have to add more veneer lines, it might look funny, as they would be on the outside.

My spruce is near full thickness, as I only did a little surface sanding after joining, so if taking it down and starting over is my only option, so be it. I'm just real happy iwth the way this set of tiles looks, especially since it is my first. I do not regret trying to make my own on my first try, but now understand why so many beginners and experienced builders buy the pre made rosettes. Alan C., if you are lurking in here, it's ok to tell me "I warned you......" (about keeping it simple on the first few tries);-)
Ken

Eduardo Brito - 10:16am Feb 26, 1998
Classical, Steel string and Solidbody guitar builder
Hi Ken, Do you own a router? If you don't I would advise you to buy one. You can easily drill different radius holes on the router base and take care of any size rosette channel that way, both the depth and the width will come out perfect every time. All you have to do is set up a pivot pin on a flat scrap board ( I use a piece of plywood) were all the holes fit and drill a hole on the soudboard at the center of the soundhole to allow it to be attached to the board. After that, set up the router for the desired depth and rout away. You can easily test your setup on a piece of scrap and try the rosette for a fit beforehand. Use the same jig with a smaller radius to cut thru the soudboard to form the soundhole. Also, I believe you shouldn't be afraid of trying anything difficult, because only practice makes perfect, go for the hard stuff and you'll learn that much more, even from your mistakes.

Ken Whisler - 08:19pm Feb 26, 1998
Thanks Eduardo. I do not own a router. I wanted to do my first by hand as much as possible. I am far enough into this one to know there will be more, so a router is in the not to distant future. I used Cumpiano's "popsicle stick" method and carved it out with a 1/2" chisel. It worked. BTW, I do have Black and Deckers rotary tool, their version of a Dremel. With the right attachments, could this work as a router? I have been told a lot of Dremel's accessories will work with the Black and Decker. I have never used it; it was a Christmas gift.
Ken

Tim Talbert - 10:06pm Feb 26, 1998
Ken, I use a circle cutter on a drill press for this job. I understand you don't have one, but perhaps you could get access to one. My circle cutter has a small twist bit at the center that you set to the center of the sound hole. Next, there is a cutter with the bevel in, set deeper than the next two, this cuts through the soundboard to make the soundhole. Next there ia a cutter placed bevel out, this cuts the inner edge of the rosette channel, last there is a cutter, same depth as the last, that cuts the outer edge of the channel (bevel in). I route close to the lines, then clean up by hand. Getting your old rossette out, hopefully intact depends on the kind of glue you used, see the discussions on that topic.

Bruce Taylor - 03:22pm Feb 27, 1998
Ken, if I understand your message rightly, you've already glued in your rosette, but you forgot to inlay a whole circle of mosaic tiles and/or veneer lines. So, you now have a rosette pattern that is not symmetrical. If the missing lines belong on the outside perimeter of the rosette, you might be able to rout (or chisel) a new channel around the central motif (avoiding the necessity of trying to remove your rosette). If you attempt this you should remember that the central motif of your rosette might not be perfectly circular. So, if you use a mechanical circle-making device (such as a fly-cutter, rosette-channel tool or even the Cumpiano/Natelson popsicle stick) you risk paring off pieces of your main motif, or leaving scraps of the unwanted veneer lines clinging to the outside of the mosaic design. If you have a steady hand you might be able to cut the inner perimeter of your new channel with a scalpel or X-acto blade (you might make judicious use of a circular template to guide your cut). If you are not confident that you can do a clean job, it might be safer to rout out the whole rosette and start fresh.

Incidentally, if you decide to start again you might try building the complete rosette outside the guitar and then inlaying it (using the method that Irving Sloane gives in Classic Guitar Construction). The method has certain advantages for a beginner. If you build the complete rosette separately (instead of assembling it right on the spruce top of the guitar, as Cumpiano/Natelson recommend) you can proceed in a slow, leisurely and organized way. The hardest part of the process is installing the completed rosette after you've built it. A rosette that you've assembled around a Sloane-style circular mould is not likely to be perfectly circular on its outside edge. Even if you are very careful, chances are good that the rosette will be slightly bumpy or elliptical (in which case it will not fit well into a pre-routed channel). You can get around this difficulty by using the rosette itself as a template for cutting the shape of the rosette channel. Use double-sided tape to temporarily affix the rosette to the guitar top. Take a sharp X-acto knife and cut (to a depth of about 1.5 mm) all around the rosette (on both the inner and outer edges). Proceed slowly, being VERY careful not to shave any wood from the rosette itself . Once you have defined both edges of the channel, remove the rosette and rout out the wood between your cuts (or chisel it, if you are a masochist). The result is a rosette channel that perfectly matches the almost-perfect shape of your rosette.

Let us know how it turns out.

Dean Harrington - 10:17pm Feb 27, 1998
Ken,
Stew-mac sells a rosette attachment for the Dremel and it works great. this is the only thing that I think the dremel works for in guitar building. It's too weak for cutting binding but it will work if you go slow and make many passes. i made three guitars with only a dremel before I bought a laminate trimmer.

Ken Whisler - 12:07pm Feb 28, 1998
Thanks all for the input. Bruce, I followed you suggestion and chiseled out the remaining width. I glued a couple of peices of tile with veneer lines from the outer motif and used that as a guide to cut the correct outer diameter and chiseled it out with a 3mm chisel. The corner of my exacto razor saw was very useful in the clean up. Masochistic? I was up half the night making the remaining channel and after a 2 hour nap got up and spent the better part of the morning laying in the remaining tiles. About twice as much time as if got it right the first time. But now I have two things: my original rosette pattern in tact and the knowledge to make it easier the next time, thanks to all of you who responded.

BTW, has anyone used natural varieties of wood to make tiles as opposed to colored rosette sticks? i.e.; a pattern of , say, purple heart, cypress, cedar, spruce, etc.

BIG THANKS!
Ken

Bruce Taylor - 06:36pm Feb 28, 1998
BTW, has anyone used natural varieties of wood to make tiles as opposed to colored rosette sticks? i.e.; a pattern of , say, purple heart, cypress, cedar, spruce, etc.
I like to use natural veneers. I buy sheets of 1/40" holly, padauk and satinwood from Constantine's & process these into "sandwiches" from which I cut the strips that make up my rosette logs. I've used macassar ebony veneer for the black parts of the rosette design, but since this is expensive (and a little hard on my saw blades) I've switched to dyed maple. I've never used pre-cut sticks, but when they became available from LMI I ordered a few bundles, just to play around with. Did you use LMI's sticks, or is there another source?

Ken Whisler - 09:43pm Mar 1, 1998
I used LMI's. Our local Woodcraft has a selection of veneers, individually and in variety grab bags.

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