Official Luthiers Forum!

I'm wanting to do something just a bit "different" to the norm on my next build, possibly a Trinity knot for a rosette. This presents a problem though - how in heavens name do you cut an oval channel for a rosette (without spending daft sums of money on one of those oval cutting jigs)? .... also, for tackling this type :



how would you go about cutting the lines at right angles to the circle of the soundhole?

thanks all

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imagination is more important than knowledge, knowledge is limited, imagination encircles the world

Probably a number of ways to do it. Thin metal template and a scalpel. I've even tacked on rosettes and carefully scribed around them with a scalpel. It's not that much different from the method of inlay or scribing around the bridge in order to remove the finish.

ahh ok Michael, I wasn't thinking at all of scribing (bit of brain fade!). So I could use my French curves to create the shape I'm after, scribe with a scalpel round the plastic of the curve and just route to that line like when doing inlays? .... seems reasonable thanks

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imagination is more important than knowledge, knowledge is limited, imagination encircles the world

For something like in your picture I do it like a lute rose, just plot out what you want cutting with pencil on the wood and cut with scalpel, chisels circle cutter etc. looks harder than it is... you just have to watch for crushing spruce when cutting hard across the grain.
For the 'trinity' circle thingies I believe you just plot a triangle of 'centres' around your sound hole centre and use those points as centres for your circle cutter/router.

P

thanks Peter, using the scalpel isn't too tricky - I'm a dentist in "real life" My only concern would be the slight "crushing" of the wood when cutting across the grain as you say. Yup - I could do the Trinity knot like that, great stuff

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imagination is more important than knowledge, knowledge is limited, imagination encircles the world

Make friends with someone who has a CNC machine

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I would propose marriage to someone that has a CNC machine

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imagination is more important than knowledge, knowledge is limited, imagination encircles the world

Easy now Rick! Andy don't play dat!


Posted using two tin cans and some string.

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http://www.CostaGuitars.com
PMoMC

haha!! .... maybe I'll just marry a CNC machine then. Or find an elusive woman who has one. There's bound to be one .....

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imagination is more important than knowledge, knowledge is limited, imagination encircles the world