sorry @Helvetosaur with trimming the spheres as you suggest, there will be half of the sphere, and the connection will not be tangent (the big sphere has to "contribute more then 180 degree, the smaller less then 180…)

so maybe one of those other ways:

- Draw a line between the two sphere centers
- set the _cplane by x-axis from center to center.
- redraw the circles - corresponding to the spheres
- connect them with a tangent line
- extend the axis to trim the circles, join the resulting curve
- do a revolve (marked / yellow in the screenshot)

(sorry i reversed big and small radius, but the workflow is the same…)

i left the c-plan orientated in the screenshot…

hope that helps - best -tom

Mace_Keule_00.3dm (148.3 KB)