Official Luthiers Forum!

It's the little things about building guitars that gets me.....I recently bought a dremel, precision router base and rosette routing jig from StewMac for cutting rosette channels. I just don't see how to adjust it to get the precise cuts needed for a rosette. Especially since I want to try an ab ring in a wooden background with perf between them all. Between the generic ruler on top of the rosette cutter, the set up makes calipers difficult to use and the spiral bit makes getting cuts witin a few thou seem pretty difficult.

Trial and error comes to mind (my first failed attempt). Then I thought I can print the rosette design from autocad, glue it to the top and use the lines to adjust the cutter (haven't tried this one yet).

How do you use yours?

Thanks,

Laurie

_________________
____________________________________
Time you enjoy wasting is not wasted time.

Trial and error. There is always a little test patch that will be covered by the fb ext.

For rosettes, I use a scrap piece of wood to set up critical cuts. Doesn't take too long, and seems to work well for me. I'd also be interested in hearing other meathods.

Aaron

_________________
Aaron Craig

I use a drill press circle cutter with high speed steel cutter bits that I have ground to specific thicknesses on my grinder. I install a bearing in the soundboard that fits a quarter inch steel rod that I installed in the circle cutter instead of the drill bit that normally is there.

_________________
Old growth, shmold growth!

Laurie: I use a laminate trimmer in a home made base. For set up I use dial calipers and make measurements between the pivot pin and the cutter. You can measure outside to outside or inside to inside but be sure to think through to determine if you add or subtract for either the I.D. or O.D.
Tom

_________________
A person who has never made a mistake has never made anything!!!

Where can you buy a Wells-Karol router jig?

_________________
"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Aaron,
Did you mean other meatheads? If so, I can talk all you like!

I have used the dremel for about 10 years and get same results as when used Foredom or drill press. Good tight fits. That said I am going to go with the compressor rig that John sells.

On the dremel lay out on your top the beginning and then the width with a pencil. Go shallow all the way around on first cut and then deeper to desired depth. For me I make the depth so the top is proud of the rosette piece. For me getting depth right first is important. This is because as I widen the channel, the depth remains the same and a flat bottom to the channel. This for me helps not to get into sand through in the purf if using that.

I use a 1/8 or 1/16Th bit and as I widen the channel, cut about 1/2 the width of the bit. This keeps for me tear out and again uneven channel bottom for the rosette to sit in. As I widen the channel and get close to final, I set the rosette in for test fits until I get the thing to set tight and for glue. Since the rosette is lower than the top, I can send it through the drum sander with 220 (just my choice as I have had success with that grit) until the rosette is even with top. Again this keeps me from ever having tear out and sand through. I have plenty of the back of the top to get then to final thickness with the drum sander. I can say I never have tear out or sand through in the purf if using multi lam purf. I get tight and even fits.

Like I say I am going with the air rig but just because want to try it. It is a faster speed and like some said bearing better. But the dremel rigs work fine and particularly if only building a couple of guitars a year. Or for that matter 15 or so a year. I have used the LMI rig, various fly cutters, Foredom etc. All work fine, but you can do just as well with the dremel and Stew Mac stuff.

It isn't always what is used, but how it is used

http://www.facebook.com/media/set/?set= ... 4209cb309b

Here's a link to a photo album I'm making on Facebook, you can see how my setup is with the circle cutter. The whole setup is cheap, about $30, it will install any rosette that is round, requires no special routers or jigs, is easily adjustable with ultra fine precision, and the results are flawless and able to take into account material differences. Best of all, you can see exactly where your cuts are going to be without any obstruction whatsoever before you excavate wood.

What sets this setup apart from others I have seen is the bearing guide that keeps everything centered perfectly and repeatably without wearing the wood or relying on tacks that can bend or move in the wood.

I excavated the wood for the abalone rosette in less than 10 minutes, and it was easy, the herringbone rosette pictured with the circle cutter took about 2 minutes to trace it out, excavate the wood for the rosette, and glue in the herringbone and purfling strips.
.

_________________
Old growth, shmold growth!

I did the trial and error on scrap ONCE for each cut ring. Once I had it set right I cut the circle into a piece of plexiglass. Now to set I just put in the center pin, slide out till the router bit drops in the desired ring and then tighten. Been using the same plexi piece for years. I also use it to pre-bend my B/W/B wood strips, wet them and force into the plexi ring and let dry. Then they drop into the cut slot easily. Remember to use a scraper and bevel off the bottom corners though both for the bending and before inserting in the cuts in the top.

Alan D.

I drill and install the centre pin in the soundboard first, then use a vernier calliper to measure from the pin and mark with a knife under the fretboard area(allowing for the radius of the pin)
A marking knife is much better than using pencil
For segments wider than the bit, start a little inside or outside the mark and creep up on it with the last cut really fine. Ckeck against your rosette as you get close.
Make sure you tighten the depth adjusting screws REALLY well as they can vibrate loose.