The "D" shaped shaft hole in the original black lever was 5/32" diameter.
Over time the hole had been worn round. I drilled through the lever and 5/32" shaft
and inserted a dowel pin. That worked for awhile, but any dowel pin (or
spring pin or cotter pin) small enough to go through the hole was small enough to
periodically shear off, and it faithfully did.
A new lever was fabricated out of aluminium. It's longer than the old lever.
I didn't have a "D" shaped broach (a "D" shaped metal punch) so I created the "D" shaped hole as follows: