Rosette cutting jig for oval soundholes

[Herman]

Making an oval soundhole and rosette is coming up and I was thinking how to make an easy approach to cut the rosette.
At SM you can buy a base plate for this job, but getting it to Holland would make it a 100 bucks.
So I made me a similar jig. A bit wider for maximum stability and a bit shorter, 'cause the soundhole will be only 57 mm wide.
I looked for a nut with the Dremel thread, but I could not find one here. That is why I glued the collar of the standard Dremel into the block with epoxy. Some cuts were made for good grip of the epoxy.
For fixing the bold I glued a nut into the base side. Simple and ferm enough to do the job.
This is how it looks:

[Dave Bagwill]

Hey pretty nice H!!

[John Parchem]

I looked at it a couple times and I have trouble seeing how it makes ovals. Also does it limit the oval to an ellipse.

Thanks

[Herman]

Hey John
It is supposed to work like this:

[John Link]

The SM tool will cut a purfling channel to the contour of an already cut sound hole or other edge. It was originally designed for setting purfling along the complex contours of a violin plate.

[John Parchem]

I get it now I have used the SMac tool for violin purfling.

Nice