How to cut a part and inset that fit well? - Fusion 360, Wood

I’m using Fusion 360 for most of my CAD/CAM work, but there is one technique I cannot figure out.

I want to take a part that I carve out, and inset that part slightly into a base. I typically will create a sketch, then do a few extrudes to create two pieces that fit perfectly together on screen (of course). But when the X-Carve is done cutting them out, they don’t remotely fit together. The pocket dimensions are somehow quite off from the part’s dimensions. It’s on the order of 2-5+ millimeters - too much to sand or pound into place.

Using a 1/8" end fish tail, I put a 1/16" radius on all the corners. I cut out the part with a 2D Contour. I’ve tried a couple approaches for the inset pocket in the base. A 3D Pocket, with the tool set on all the “Tool Inside / On / Outside Boundary” options in different tests. And a 2D Pocket (which doesn’t have those on-boundary options). All the results were pretty much the same.

It seems like this should work, give or take the idiosyncrasies of natural material requiring persuasion with a rubber mallet. A worst I could figure out a consistent over-sizing of the inset pocket. But that feels hacky to me and prone to mucking up other features of the design.

Any suggestions?

Part and Inset.f3d (138.5 KB)

Do a test piece in Easel only, to find your particular machine “offset”.
Do for instance a 250x250mm pocket and a 250x250mm “inlay” and measure that difference.

In Fusion you may have "“Stock to leave” functions enabled and to rule those possibilities out its best to do the test piece in Easel only.

An Xcarve do not have the precision to carve with zero offset as pockets will be a smidge undersized, and outlines a smidge oversized. Most machines dont BTW, atleast those that do not allow tool path / tool wear / backlash compensation.

However, this should not amount to 2-5mm, but I hope the Easel only carve will provide more machine specific information :slight_smile:

Thanks Haldor,
The Easel-only test was definitely closer in size, probably more like what you would expect based on your comment.

I haven’t figured out a consistent ratio yet, but by fiddling with negative Stock To Leave values in F360, I did manage to get a pocket that fit the piece, albeit a little too loosely (which is progress!). I basically cut a test pocket, and a piece, and then measured the difference and fiddled with the negative Stock To Leave. I’ll tinker with this some more–thank you for the sanity check!