I have an old Kenmore Cannister Model 116 vacuum that works perfectly fine. However, the coupler on the pole kept breaking. The original fix involved epoxying some reinforcement around the coupler, which worked fine for a couple of months. Eventually the epoxy let loose and broke again.

Did a quick sketch in Fusion360 and played around to find the correct size and hole placements. This doesn't include the cable guide or some random inside geometry, but it just works.

Actual replacement part on eBay: $18 + Tax + Shipping

This 3d printable replacement part: 49 grams of filament + a small screw