Hi Jim, it's coming along well!

> A Bool union gives a bunch of cuts through the wheel
> which I kind of hate to see, but maybe that doesn't
> really matter?

Could you maybe explain a bit more what you mean by "a bunch of cuts through the wheel" ?

Do you mean you have some excess material sticking into the wheel that you want to get rid of, sort of like this area shaded red here:



If that's what you are talking about, then one easy way to get rid of that is to do a boolean difference on the body piece as a separate step first, to carve off that area that you don't want, before you combine the body and the wheel together.

That would go something like this - draw a curve in the side view that will divide the area you don't want off:



This looks like this in the 3D view:



Now select the body and run the Boolean Difference command, and select that curve as the cutting object, that will divide the body into 2 pieces:



And then just delete the piece that you don't want:



So one thing to note is that it's kind of easier to not try and make the dividing line go along the exact same area as where the wheel will contact the body, try to put it in the in-between zone - note how I drew the cutting arc above. If you try to make it follow exactly along where the wheel will contact the body it is a bit too easy to be off in the wrong direction and end up with a little hole there when you union them together in the next step.

There are some other ways you could approach this as well, like the Trim command can be used to slice the objects with one another and then you pick which pieces you want to have discarded.

But just carving off the piece you don't want with boolean difference is probably the easiest way.

Also another possibility is to use the Boolean merge command, which will also carve things up into multiple volumes and you can delete the part inside the wheel that you don't want, and then select the other parts and union them back together again.

- Michael