Hi Dave,
The channel for the key ramps up gently on the inside end. Is there any possibility that pushing the sprocket on created tension knowing that the end of the key will be pushing up out of the channel?
I initially thought it was missing another collar or something on the inside, but the sprocket is hard up against the motor to make the chain line up.
Usually if there is no grub screw or bolt at the end of the shaft there is a Morse taper on the shaft and hub ,but the tapered keys have a rectangular varying cross section. The basic idea of using taper keys is for mainly for the ease of assembly and removal of the key. Further due to the tapered section of the key along its length, it acts as an axial retainer for the mechanical power transmitting element.
The purpose of the taper is to secure the key itself, as well as, to firmly engage the shaft to the hub without the need for a grub screw. The problem with taper keys is that they can cause the center of the shaft rotation to be slightly off of the mating part.
If there is a tapered ramp for the key it would depend which way the ramp goes as to if you can fit the hub on the shaft and then hit the
key in with a small pin punch .
Cheers
Max.
