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Steve, I was not able to find plans for the Wells-Karol Jig other than the ones I would have to pay for from Sylvan Wells' site.

Do a Youtube search for "making a precision router base" and Chris Paulick's three videos should show up. You may want/need to adjust some measurements slightly, especially if your proposed laminate trimmer is not a PC 7310 like Chris's.

I just watched and rewatched them while making notes until I had what I needed. I think mine cost me about $4; the UHMW was given to me by the local plastics shop, and the bolts I scrounged from stuff others threw away. Far and away the best time and money I have spent on guitar and jig making.

I did with a chisel, and also with a router. Using the circle cutter before the router prevent chip out and give a really nice clean cut.

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Francis Richer, Montréal
Les Guitares F&M Guitars

Just to offer another way........

We use a drill press rosett cutter.......... especially designed that has 4 adjustable knives ....... that are ground to custom size......... (Luthiertools which we sell)

We use laser cut templates to adjust the cutters on the fly as needed ..........

Anything unusual or different we cut with the laser...... (oval, rope, etc.)

Kevin

I just ground a HS steel cutter on my grinding wheel to .02 using my digital caliper.
Where would you get a router bit that small for a dremel or laminate trimmer setup?
I would imagine they'd be quite expensive and weak, and break pretty easy, too.

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Old growth, shmold growth!

I bought a trim / laminate router and it comes with 2 rods that screw in . I glued up a block from ebony to make a centering block and will post a pic when its done . I just happened to be doing exactly this when the post was started .

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So far I'm pretty unsatisfied with using a dremel, but have yet to get a good spiral bit which I'm sure will help. The problem with drill press cutters unless you just want to cut a hole, is they have to be perfectly level with your table, which can be a pain the u know what to attain. But I do have a made in china drill press so I might not know what it's like to have a good one. I've made several attempts for use with a laminate trimmer too. Still not quite there.

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"Preoccupation with an effect gives it power and enhances the error"
from "Your Owner's Manual" by Burt Hotchkiss.

Wow!!

Thanks to everyone for these informative replies!
This is a clear example of your diverse ingenuities.

I would like to respond to some specific posts.

Dave F - That digitized Stew Mac jig is very cool! Thanks for posting it.

Todd, Jimmy, Scott, Robert, Tony,
Thanks for your comments about the Wells/Karol - or Karol/Wells jig. An elegant design.

Francis and Doug,
I like low tech - as in low noise and low airborne dust. Your manual methods appeal to me, especially the idea of turning the drill press fly cutter by hand.

theguitarwhisperer,
I wasn't in favor of using a drill press fly cutter at machine speed until I read about you experience with it. You now have me second guessing myself. "No fuzzies" and the availability of a solid, well made and reliable tool sounds very good. I already have a drill press but not an appropriate lam trimmer, Foredom, Dremel, precision router router base or circle cutting jig. But, as Nick said, I wonder about the precision of my drill press and my ability to get it perfectly level. I'm going to see how well I can adjust it and if it looks good I may try this method.

I notice that no one wrote about the LMI-Greven drill press rosette cutter. Anyone here ever used it?

Thanks again to everyone.
Vivian

I actually have both LMI rosette cutters, the old style and the new style.
It was impossible for me to set up easily and accurately, without doing lots of test rosettes on scrap wood, and I ran out of scrap wood! Forget about doing more than one style of rosette, it would be a nightmare!
I learned the circle cutter method from Cumpiano, in his shop.
From my experience with the LMI cutter, I applied the center bearing concept to the circle cutter, and that sealed the deal for me.
I have a Chinese drill press, and had no problem getting the surface level and perpendicular to the flywheel, but yes, that is an extremely important consideration, as the tolerances are so tight. That would be a good argument for the dremel or laminate trimmer method, if you can't true your drill press.

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Old growth, shmold growth!

I did the same thing, but got the version for the PC-310. Pricey, but a really fine piece of engineering, and superb workmanship. I use it for many different tasks.

-Mark

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Pullman, WA

The more I know, the more I know I don't know.

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I use a fly cutter but I've added a moveable counter balance made from an old plumbing part that makes it run much smoother.

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

Can you post a picture of your counterbalance? I run mine at a low enough RPM to run smoothly, but every little bit helps!

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Old growth, shmold growth!

My counter balance was just an old brass fitting that had some weight to it. I cut part of it off that wouldn't fit, drilled and taped it for a 1/4 20 bolt. I put the bolt on the facet that had the end stop in case it came loose. I only run at about 500 rpm but it still helps. I wish it were a little heavier for wider rosettes. Maybe I'll find another chunk of metal sometime that I can tap, but it works for now.

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

i'm sort of ashamed to say it, but i have the LMI grevan cutter and i don't use it. I thought it would solve some of my problems with poor fitting rosettes, but i overhauled my process and now have great results.

I think if i were going to settle into making the same channel cuts for each guitar i build, i would probably take the time to set it up. in the test runs i did, it worked very well. i would regrind the cutting tools though to reduce chatter and burning.

b

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brendan 3.0 new and improved, with better interpersonal subroutines

Hi Brendan,

What method are you using now that is giving great results?

Thanks,
Vivian

Just to round out the discussion, there’s also the low-tech approach, a homemade rosette/circle cutter:




Joe

That thing speaks to me. Nice job Joe. I'll be copying that one.

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Hutch

Get the heck off the couch and go build a guitar!!!!

Thanks Hutch. The cutter blade is from Ron Hock, similar to the blade he makes for LMI's rosette/circle cutter but longer. The longer blade makes setup and honing a little easier. The body is a little over 5 inches long, made out of Tigerwood. The pivot pin is just a door hinge pin; the workboard is 1" MDF. Good luck.

Joe

i jurry rigged a Bosch colt with the LMI circle cutter for adjustment. I build my rosettes on a thin piece of baltic plywood. Once it's all laid up on the plywood, i run it through my drum sander to take away the remaining plywood exposing the rosette through the back side. Then i setup the router to cut out the rossette (outside first, then inside.

Then i can accurately rout the soundboard based on the width of the already laid up rosette. I always had a lot of trouble starting from a channel cut, then trying to cut pieces to fit the channel.

b

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brendan 3.0 new and improved, with better interpersonal subroutines

Same here with the Cochran base and 310 PC. It's a joy to use.

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Anderson Guitars
Clearwater,Fl. 33755

Long time ago I tinkered together a tool very similar to Joe's. It works great, but there's a serious drawback or two: It's real hard to see precisely where your knife will touch the top, and a little tricky to make very small adjustments. However, by testing on scrap, you should be able to work around these two issues. The price is right, and you can improvise a cutter from an old jig saw blade. I used an antique router plane to remove the waste and level the bottom of the channel--a little tedious, but fun. But I'm not on a production schedule, so the added labor time didn't matter.