www.KitGuitarsForum.com

After cutting a couple of rings of cocobolo (see previous post) for a rosette, i needed to thin the rings to about the same thickness as the MOP that will be used with it in the rosette. Coco is pretty brittle stuff, though and sanding or scraping it without some form of support will leave you with curved shards of a ring.

So, I used the trammel cutter again with my router (see previous post) but made the ring-shaped groove in a piece of plywood, but only deep enough to contain about as much thickness of the ring as i wanted. The ring was set back into the groove, back side up, and i used a cabinet scraper to peel off nice shavings until the exposed side of the ring was flush with the top of the plywood. The photo shows the setup.

BTW - as the ring gets thinner, it becomes increasingly fragile. It can be glued back together invisibly with a bit of thick cyano and a dab of accelerator. A little scrape with a razor blade and a touch with sandpaper to remove any residue, and it looks good as new. Guess how i know.
bert

Way to go Bert, that is a good way to handle that wood ring.

Bert,
You're on a roll!

Looks good. Have you tried just gluing the thicker ring in the top and doing the same thing in place on the top.

Nope. This seems safer and a lot less risky - if the workpiece breaks while i am thinning it in this fashion, no biggie - cut another, start again. If I mount it in the top, and the scraper slips and gouges the spruce, that would be a problem for me. Considering that one of the unexpected side effects of carpal tunnel surgery a couple of years ago was that the pads of my thumbs are numb, i'd rather do delicate work away from the sitka. One slip on a piece of plywood - no trouble. On the top, maybe big trouble. Also, if you have ever used a cabinet scraper, you know how much downward pressure and force is needed to draw or push the scraper, especially when scraping a hard, resinous, brittle wood like cocobolo. You need to be able to stay in control of the tool. Numb thumbs - can't feel the scraper very well. So - not saying it couldn't or shouldn't be done as you suggested; I'm saying I shouldn't do it that way.

bert

Sure, whatever works best for you. I am not a good enough woodworker to get all of the rosette components in the top at just the right height, so I end up going a bit proud as I would rather scrape the rosette than scrape the spruce down to meet the rosette. I also start with a ring close to the target thickness.