After five years, the adapter between the Kenmore Progressive vacuum cleaner and the long wand required to reach inside the refrigerator evaporator coils broke at the latch opening:

A quick fix let me continue the mission:

A better fix required a few minutes of OpenSCAD tweakage and a few hours of hands-off build time:

The fitting ID is now 2 mm smaller, the 3D honeycomb infill is 25%, and (contrary to the picture) it now has 4 perimeter threads. It’s a two-line change from the last time:
OEMTube = [35.0 - 2.0,35.0,41.7,40.5,30.0]; // main fitting tube
… then, inside MaleFitting() …
cylinder(d1=OEMTube[ID2],d2=OEMTube[ID1],h=2*OEMTube[LENGTH] + 2*Protrusion);
Those will propagate to anything I build from now on, although this is the first latch fracture.
Gotta love it when 3D printing lives up to the hype!