Official Luthiers Forum!

What type of bit(s) do most of you use for rosette routing? It seems like a spiral downcut would be the best to avoid damaging the top surface.

I'm having trouble finding a "small" bit less than 1/8" (something like 3/32"). I see that Stewmac has one but the shank is less than 1/4" and requires an adapter which I would like to avoid.

How about end mills? Other types of cutters?

Thanks,
Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Lee Valley sells 1/4" shank, small cutting diameter bits. I have used these with excellent results using my PC 310 and Jasper Circle Jig, getting absolutely clean, no tear-out channels for rosette inlay. I also run them in my Foredom 44 handpiece. That particular handpiece has collets for 1/4" and much smaller shanks.

The 7" Jasper Circle Jig is often overlooked by luthiers. Using different bits and various locations of the pin, adjustments in diameter of cut can be varied to 64ths and smaller, depending on your luck and skill with miniature bits.-Jasper supplies the formulae for computing the results of the interchanging. The small Jasper sells for less than $30 USD. It is the model that is about 7" in diameter.

I put together this setup for my first rosette in 30 years and got perfect fit of abalone and purflings and then the soundhole cut.

After the first cut, I did not even have to hold my breath .[img][IMG]http://i85.photobucket.com/albums/k65/edmunds4bar/inlay%20and%20related%20tools/th_DSC_0034_1.jpg[/img][/img]

You can use industrial end mills, available in thousandth inch increments from the usual suppliers. They come 1/8" shank, adapters are readily available. A lot cheaper than the bits sold by lutherie suppliers, and every bit as good or better.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

bqtool.com had carbide bits for very reasonable prices .

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

And while you're there you might want to stock up on smaller sizes for inlay.

Thanks!

I definitely like the prices from bqtool but I'm a little confused.

What are the shank diameters?

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

the shaft is 1/8 inch.. Call them and they can help you out . You want a sharp bit . Often I see people that used the down cut have issues as the down cut can push the wood fibers into the cut , once sanded they fall free and the tight fit becomes loose.
At these prices you will be able to use sharp bits and not break the bank

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

So, exactly what type of bit is best for rosette routing into Spruce ??
Gregg

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Gregg

I like the stewmac 1/8 shaft, 3/32. Dremel router setup for rosettes.

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Jason Moe
LaCrosse WI 54601

Kevin,

Is there a reason for shying away from the 1/8" reduction collar? I was also concerned about that but after it was recommended here I tried. As long as you do not overtighten the bit you will be fine. We are working with softwoods in very shallow depths so bit torque and movement are not really an issue. I used mine in a PC 890 series and it works fine.

It's just a psychological thing. I had a problem with paying almost $20 for a straight bit that also required an adapter and probably can't be resharpened. The $7.00 cutters from BQT seem much more palatable.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Get the adapter - it will probably last forever if you don't lose it ,but more importantly it allows you to take advantage of a whole lot of bits that you otherwise just couldn't use.

_________________
Steve Smith
"Music is what feelings sound like"

So is an up cut spiral bit better than a down cut one?

I looked at the bqtool site and was a bit overwhelmed, having no idea where to start. Should I get a square cut stub bit or what? I am a complete newbie at this and have always used a dremel or small cheapo straight flute bit in my laminate router, with pretty unsatisfactory results sometimes. I know this needs attention and have been wanting to get a few end mills for a while, but am a bit befuddled by those big industrial catalogs with hundreds of different choices.

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

I use a down spiral to avoid spinter and a ragged cut. I depth of cut is small and creeping up on it is advisable so clogging the bit is not really an issue. If you worry about dust in the cut creating a false measurement, make you sure you clean the cut with compressed air or whatever before you measure. I do not have research to back this up, but the air movement created by the turning bit should do a good job of keeping the cut clear.

If you aren't in a big rush, then you can use a knife gauge to very accurately cut the inside and outside line. Then the router is just an excavator. If you are in high production matching the bit to a perfect cut for your rosette makes sense, but at my level of production it is easier to take an extra minute an eliminate any potential for error.

I have a fancy gauge, but traditionally people would just stick a knife through a strip of wood, and drill a pivot.

In theory a downcut bit should be used for rabbeting, since the swarf can drop away, and an upcut bit for slotting. In practice, for what we do, downcut works for a slot, and upcut is more likely to fluff the fibers at the top edge of the cut.

_________________
Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Up cut or down cut is not as important as having a sharp cutter, spinning those small cutters very fast, and to move the bit at a good speed - not too fast and not too slow. It should cut by removing a chip, not powder, and never burn. If it burns the bit is moving too slow (IPS, not RPM) or is too dull. Cutting with a coat of shellac is very helpful. I'd prefer to use down cut, but more important to me is that I use the right size and sharp bit. I have end mill bits as small as .010". Last time I checked, down cut is not available any where near that size.
Another thing to remember is to cut a depth of about 1/2 of the diameter with each pass with these small bits. You'll break them if you go too deep with one pass.

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

I looked at the bqtool site and was a bit overwhelmed, having no idea where to start. Should I get a square cut stub bit or what? I am a complete newbie at this and have always used a dremel or small cheapo straight flute bit in my laminate router, with pretty unsatisfactory results sometimes. I know this needs attention and have been wanting to get a few end mills for a while, but am a bit befuddled by those big industrial catalogs with hundreds of different choices.

I agree with Nick. Can someone (John?) tell us which BQT bit is equivilent to the STEW-MAC 3/32" bit?
Steve

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

when you call to order just ask them for the same bits we use at Blues Creek . It is the square end mills , 2 flute. I use 1/32 .020 and 3/32 . Email me and I can send you the PN

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Get a 3/32" and a 1/32" set on ebay. 10 for $25 last I checked. They will last forever. But they will break eventually. Expecially the 1/32". Maybe its 1/16"... whatever. Get a 1/4 to 1/8" adapte from Rockwell or Lee Valley. No issues. I assume you are using a Wells-Karol jig or similar. I believe those ebay bits were used in CNC, resharpened and resold.

Mike

John,
The bits being talked about in this thread are for cutting spruce,
What bit would you recommend for triming pearl ??
For example grooming the inner or outer edge of a pearl rosette.
Gregg

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Gregg

thanks for the info.

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

The end mills from BQTOOL are designed for metal. I use them for pearl and wood. They do the job . Howard K is dead on the money . Up cuts are what you need . Actually SHARP is what you need . Down cuts can appear sharp when they are not. Once the pushed over fibers are sanded off you open the cut another /.010 and things loosen up.
All I can say is try them once and you will like them I am sure. At that price you can afford to replace them when they are dull.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it