On Dec 18, 5:24*pm, Jim K wrote:

Thinking similarly (but with only one spline) I wonder if car body
filler could be used to "cast" a suitable connector to interface with
your lever (that I can't picture just yet ;) ?

If you have a threaded connection at the little end of the taper, then
you can bodge out of almost any sort of filler within a tube housing.
Tightening the thread afterwards gives enough friction to grip.