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Thread: Cutting bits for rosette channels

  1. #1

    Default Cutting bits for rosette channels

    Not really directly mandolin related but I think there are also some guitar builders here too.

    Does anyone have any comparison of end mills vs downcut spiral bits? I’m looking at some sources such as precise bits and drill bit city.

    I plan to use these either in a foredom or laminate trimmer.

    Thanks, Jon

  2. #2
    Registered User sunburst's Avatar
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    Default Re: Cutting bits for rosette channels

    Down cut bits work a little better, there are special bits that are ground so that they have both "down cut" and "up cut" features. They're kind of expensive, and in my experience, a well sharpened and well operated fly cutter in a drill press can easily cut cleaner than any rotary bit.
    For oval holes hand tools are the answer for me.
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    Default Re: Cutting bits for rosette channels

    The bits I've gotten from Precise Bits are great. Pricey but really high quality. I use them in a CNC. For what you're talking about I use the the downward spiral. Remember though, that the quality of the cutter is compromised if you put it into a collet or anything else that has any slop in it.

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  6. #4

    Default Re: Cutting bits for rosette channels

    Both tools you mention are, I think, single collet size, 1/8 and 1/4 which restricts regular bits or requires stepped ones. Using any kind of a chuck with either would be disastrous. Then, one tool is fully hand held, the other has, or can add, a router base. Serious control issues either way. Jig or template necessary, but if the whole groove width isn’t cut at one time, several templates.
    A fly cutter, as John mentions, would give you easily changed radii, and can cut fine lines or widths, but…drill presses of the home shop kind have lateral play in the bearings that can’t be adjusted out, and you also have to deal with a chuck. A small milling machine with collets removes both problems, making the fly cutter a stable tool, and adding accurate depth adjustment.
    A CNC mill, as Dale suggests, is best, and more versatile as well, as long as the workpiece will fit and can be clamped solidly.

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  8. #5

    Default Re: Cutting bits for rosette channels

    Thanks Richard., Dale and John. Would love to have a CNC but not in cards yet. Maybe if my production starts to approach Taylor numbers. . I’m using Bishop Cochran bases with circle jigs, so no handheld. Bits would by necessity go into either 1/8” or 1/4” collets, depending on unit.

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    Registered User j. condino's Avatar
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    Default Re: Cutting bits for rosette channels

    The Bishop Cochran base with a good downcutting bit should work great. I've made tons of rosettes using that system. My current setup uses a micro fence which I adore because of it's 1:1 ratio- turn the dial 1 mm and the channel moves 1 mm

    Make sure to buy a few extra of the small bits so you are ready to go when the first one breaks.

    To be honest, I've made some of my finest rosette channels using a 10 cent exacto blade, a popsicle stick, and a thumbtack.

    It gets faaaaaarrrrrrrrrr more complicated when you start making them multi segmented.....
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    Registered User sunburst's Avatar
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    Default Re: Cutting bits for rosette channels

    Not to make this about show and tell, but James, that radial brown/black wood rosette reminds me of this one from a few (quite a few) years ago. It's Macassar ebony. Done with combination or fly cutter and hand work.
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    Default Re: Cutting bits for rosette channels

    Thank you, James and John, for a most humbling thread. As Inspector Callahan said, A man's got to know his limitations. Beautiful work.

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    Registered User Spragster's Avatar
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    Default Re: Cutting bits for rosette channels

    My version of an exacto and a popsicle stick.
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    Registered User sebastiaan56's Avatar
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    Default Re: Cutting bits for rosette channels

    !.5mm downcut bits are readily available on the net. I bought a few from Germany with the shaft to suit a Dremel. Took about a week to get to Aus.

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