Making a custom “squircle” cutter

I’ve just made a jewelry box for my girlfriend for Christmas - Advice on my first real project (jewelry box made from wood) - and the outer radius is a squircle (https://en.m.wikipedia.org/wiki/Squircle) which is a square with a radius that’s a bit different than a normal radius.

I’ve been thinking about buying one of these cutters - https://www.toolster.dk/cmt-rundingsfraeser-hm-radius-oe4-75mm-k8/?gclid=EAIaIQobChMIhePy1r_u7QIVkQDmCh2k9whvEAQYAiABEgI6vfD_BwE - and somehow grinding it down to have a squircle radius and then making the final radius on the box with a “normal” Makita cutter.

I’m not sure how I can change the radius on the cutter? Can I do it with the Shapeoko somehow? Could I grind the cutter down somehow? Any ideas?

so never buy a bit with a bearing for your CNC!

But I have had good luck in my cnc with one of these : https://smile.amazon.com/gp/product/B01F8XBLCY

the trick to use them is to use a “follow contour” path, and just set an outside contour of your shape (always; you don’t want the sharp point to be exactly on the edge, even 0.5 to 1mm outside is better). Also you want to first do a normal contour with a flat bit so that the only thing it needs to cut is the round part, not the depth part. (assume that little point does not have a lot of strength in it, you want the side of the end mill to cut, not the point)

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I was actually thinking if using the cutter the “normal” way on a Makita. I’m thinking of making a squircle radius of 16mm, so I don’t think it’s a possibility to do that on the Shapeoko with 1 pass?!

If you have any suggestions for doing it faster, please let me know. Right now I’m doing many passes with a round cutter. It takes about 20min right now. The result is nice, but it takes a long time.

yeah 3D carving (or the manual equivalent) is never super fast… but it gets you any shape you want.
if what you want isn’t exactly round or flat (or V) then… it’s usually the only real way to go to be honest.

unless you’re a handyman wizzard, manual routing is a few orders of magnitude less precise than your shapeoko… 20 minutes may seem like a long time compared to doing something by hand… but you need to factor in the time to fix the manual mistakes :wink:

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Not to mention the time to construct jigs! That’s the time-hog for me.

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You guys are probably right. I was just hoping I could speed up that step somehow :stuck_out_tongue:.

SQUIRCLE

@WillAdams Is this a challenge worthy of your programming attention? :smiley:

It is unfortunately not suited to OpenSCAD which I’ve been working in lately — will have to see about doing it in METAPOST.

@CrookedWoodTex Programming it is not the issue. I’ve already designed it in Fusion 360 and cut it using Fusion 360 as well: Advice on my first real project (jewelry box made from wood).

I was just looking for a more speedy way for doing the squircle radius.

Are the squircles the corners of the pockets in plan view or the ‘slope’ of the sides of the pockets?

It’s the outer radius of the box.

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