Official Luthiers Forum!

I'm having a hard time cutting out perfect circle rosettes when doing radial type rosettes. For those of you that do it, what is your setup? Pictures help a lot! It seems like I get a spot where the double tape loosens up and therefore it moves making an uneven cut. Thanks in advance for the help!

I can't give you much input on your router setup since I cut mine on a CNC machine. But as for the double-sided tape, I gave up on that shortly after I started trying to make these rosettes. Now I glue all my pieces to a sacrificial board before cutting. Some watered down wood glue, or hide works well. I use light clamping pressure to attached the wood to my sacrificial board. Then once the pieces are cut I can usually remove them cleanly with a pallet knife or chisel. This eliminates the problem of the tape letting go.

Josh

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

Another method is to cut almost all the way through the rosette and then sand form the back side to pop it out.

_________________
http://www.CostaGuitars.com
PMoMC

That won't work for me Tony because I sold my sander. One note, I didn't connect or glue the pieces all the way around. The part that world be under the fretboard was not connected, if they makes sense. Maybe that's my problem? Along with the tape

Make a solid ring. Then remove the keystone if you need to.

You could always sand it by hand....

_________________
http://www.CostaGuitars.com
PMoMC

I've been doing radial rosettes with the central ring some nice (radial) wood with zipflex on the inside and outside. I make it right on the guitar top wood. First I cut the central radial sections a little over-sized and glue them into a channel in the top that is just big enough for them to fit. Then I route the channels for the zipflex on the inside and outside of the radial ring. While doing that I trim the radial ring to the right size and perfectly circular. Is that clear?

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Pat, how do you cut the radial pieces?

If I understand what you're trying to make, it is represented in the picture below. I build many at one time by using blocks a couple of inches tall. I draw two orthogonal lines and then draw in the lines dividing it into the number of segments I'm going to use. With a compass, I draw in the inner and outer lines of the rosette. Now, I know how big the blocks have to be to contain the rosette. I cut the blocks, using the miter guide on the saw to get the angles, so that there is a large margin on the inside and outside of the intended rosette. I close the gaps in the angles with a bit of careful sanding at the disk sander. Using clamps and rubber bands, as shown below, I glue the blocks to a plywood disk, using drawn circles to position the raw rosette roughly around the center of the disk. When it's dry, I turn it to round inside and out on the lathe and then cut it off the disk. I bend the inner and outer veneers on a hot pipe. Rubber bands hold the veneers to the outside while the glue dries. An inflated balloon clamps the veneers on the inside. The bandsaw slices the completed ring into several rosettes. I hope that helps.

Filippo, that looks pretty sweet! Thanks for the replies guys this is awesome feedback.

Todd, just had to comment.
I really like everything I can see about that guitar.

_________________
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.

I am drooling as I look at that picture, Todd! Gorgeous!

I do it essentially as suggested by Filippo and Todd except that I do it right into the top. I have a little template to trace out segments onto the wood I'm using and cut them out on my band saw. The important thing is to true up the edges where the segments meet so there are no gaps and they go around in a circle nicely. That I do on my small disk sander.

Pat

_________________
There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

You can also use a wood turners method of gluing to a sacrificial board with a single layer of newspaper. Separates very easily with a flexible putty knife. Or you can lay out your rosette on paper full size and glue that on to a board.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Wow, Filippo... That is some special rosette!

Well, I've seen the Maryland Mafia in action and it's unlikely I'll EVER be able to keep up with you guys!

I'll add my little tip.
Same as Fillipo and Todd etc. except I CA the wood to a thin sheet of card then use spray mount adhesive to glue card to ply wood. Cut out ring then use white spirit to separate card from plywood. Then, install ring into soundboard and scrape off card.
Similar to what Bob wrote.

_________________
We are all in the gutter but some of us are looking at guitars.

I do it similar to Pat but I cut the end off of a flatsawn board that is the width of the rosette. I taper the board to match the angles for the pieces to fit tightly together. I slice off tiles on the bandsaw. Then I glue them in place in the rosette channel. It doesn't matter if the inside and outside curves don't fit nicely because I route a new groove for inside and outside purfling. As Todd says if the pieces are small the rosette looks continuous.

_________________
Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

About how wide are the segments you're using in order to avoid the segmented look?

+1 I'd like to know as well

My segments are about a half inch wide.

_________________
Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I make 12 segments with a 30 degree angle. = 360 degrees

_________________
Alain
_______