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Looking to end up with this from 4/4 or 8/4 rough stock


Some kind of jig to get inner and outer radius?
Any help here would be great

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"Practice enough till the results aren't hopes but expectations" forum member Peter Havriluk

I just cut 16 wedges at 22.5 degrees, superglue them on a 1/32 ply backing board (mounted on mdf with double sided tape) and run the lot through a 10-20 drum sander.
Then use a wells-carol circle cutter to cut out the rosette.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Like Colin said. Pieces pre-cut to finished dimension don't always stay that way.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

I'm guessing that Michael did all those cuts on a bandsaw. Maybe a sub-table with a pivot pin and feed stock with a couple of holes to give the inner and outer radius. Maybe just free-hand following a line. "Square" the ends of the thick segments then slice them into multiple thin ones. To build a rosette would require the ends to be fine trimmed to fit, then glued down (either in the top or on a suitable substrate) and then the inner and outer radii trimmed with a router and the surrounding purling lines fit in the channels just cut. I can't think of an easy way to pre-cut them in bulk with sufficient accuracy to get a perfect slot-in fit.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Here's another vote for cutting wedges, assembling them in a ring, and then cutting the inner and outer circles with the circle cutter of your choice.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

David Russell Young's book shows a drill press set-up to do this for a pearl rosette, but the same system should work for you.

Brent

In the video justin his assistant is cutting down the edges of the segmented sections either using a block with sandpaper or slowly rotating a disc sander to get the correct angle so the segments will butt against each other with a clean butt joint

OLF sponsor Eric Schaffer has a video on his free builder tips on how to make a slick jig for rosettes. I built one and it works great, especially for segmented rosettes. http://www.ericschaeferguitars.com/cour ... -acoustic/

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Brad Hall
Mystic Dawg Guitars

No need. Rout a trough slightly oversized. Miter and glue the pieces in the trough. Level. Make a trammel base with two center points for an inner and outer band. Rout and glue in the bands with a gauged bit, level.

any pics to help with the steps and show the end result?having a hard time to visualize this

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"Practice enough till the results aren't hopes but expectations" forum member Peter Havriluk

What you're doing is cutting the radius in situ. You mitre and glue the oversized blanks into a trough of a set width/diameter in your top, level. You then presumably are putting an inner and outer band, so you need two different radius cuts. Make a base plate for your laminate trimmer or router with two separate holes for whatever size pin you cut your trough with, and that will give you those two cuts. Remember when laying out those holes that you're measuring from the pin to the inside of the bit for the outer ring and to the outside of the bit for the inner ring. This is because you want to define the radius of the cut so you're making the cuts where you need the radius to shape your veneer. Now rout troughs with a sized bit and set in and glue your bands. Level. I don't have any pictures. For example, my rosette is a 1/2". Seal the trough with sealer to prevent the CA from staining the endgrain of the top. I inlay tiles that just fit into the trough and I glue them one at a time to make sure for a good miter with a dab of thick superglue. Once they're all in, I flood it with CA and make sure its locked in. (If you have a material that's prone to staining from CA, you can use a combination of Hide glue on the edges and a dab of thick CA for the bottom.)I level on the thickness sander, come back rout the troughs for the bands, press those in and flood again with superglue. If it's my abalone rosette, I'll cut that trough when I cut the bands and inlay everything. Flood with CA, set aside for a few hours to cure, and level.

I have Bosch Colts and my base is simply 3/8" acrylic with holes to mount it to the router base, a clearance hole for the bit and then two holes about which the pin will ride to cut the two channels. They're offset from one another so you don't weaken the base in that area.

What I do is similar to what dberkowitz describes except I do the tile assembly away from the guitar top and then install the completed rosette ring into the top. I think this is basically the same approach Colin uses.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I do it the same way Jay does it

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Steve Smith
"Music is what feelings sound like"

Steve, just curious as to how you remove the ring in one go and how you adhere it for assembly/routing

Good questions. I've tried several methods but the one I use now is to build the ring on 1/64" (0.016") birch plywood using whatever glue I feel like using but usually CA. Double-stick tape holds the plywood to a 3/4" plywood base to route the circle with a Wells-Karol jig. When the ring is complete it is easily released with Naptha. The 1/64" birch ply holds it together very nicely and is something I learned from Todd Stock. I install the ring into a 0.050" deep cavity in the top and then add inner and outer rings to finish.

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Steve Smith
"Music is what feelings sound like"

I do it the same way as Jay and Steve. I've been using poster board to glue the pieces to and when I'm done I turn it over and scrape the poster board off with a razor blade... Where can you get 1/64" birch ply?

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Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

I got the the 1/64" birch ply from Amazon but I have also seen it at one if the big hobby stores.

Sent from my SM-G930V using Tapatalk

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Steve Smith
"Music is what feelings sound like"

I used the 1/64" ply, and 1/64" maple veneer that comes in a 6" x 99" roll. The veneer was way cheaper!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Here's one using 1/64" maple veneer as a backer.



Alex



Sent from my iPad using Tapatalk

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"Indecision is the key to flexibility" .... Bumper sticker

This is my first radial rosette under construction for an octave mandolin, it's easier than I thought it would be. The tiles are CA'd onto sturdy cardboard (and to each other..) from the back of a notebook binder. I take classes with Alan Carruth, and his method is not to release the ring and then inlay it into the dado, but to level what will be the bottom, flip it over and glue it in, then plane/scrape off the cardboard. I'm a little antsy doing it this way because the show side is down when it's being made, but what the heck, go for it. I'll know how it worked shortly...

Alex - I like that rosette a lot. That's the first one I remember seeing with 8 tiles. The book matching is really cool.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Thanks, Jay. If I had done 12 or 16 tiles, the benefit of the book matching would have been lost, at least, in my opinion. Plus doing 8 tiles is like half the work, right?

Alex

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"Indecision is the key to flexibility" .... Bumper sticker