Howe's UJ-0615 joins a 3/4" smooth (Sm) shaft to a 3/4"-30 spline shaft, so you can bridge two different shaft ends without an adapter.
- End 1: 3/4" smooth (Sm) (code 06)
- End 2: 3/4"-30 spline (code 15)
Howe lists this joint family in a long list of spline combinations, so if your ends are different, check the other UJ part numbers.
Howe Performance part number UJ-0615.