I'm installing my new Tradesman 13" 12-speed drillpress and I am having
problems with the "next to the last" step. Figures, huh?

As instructed, I cleaned the tapered hole in the chuck and the tapered
surface of the arbor and set the arbor into the chuck. This worked
fine. Next, I lowered the spindle (by turning the feed handles
anticlockwise) until the slot appeared on the side. Again ... no problem.

NOW ... I'm instructed to push the chuck and spindle arbor up into the
spindle to "engage" and "lock" it in the inner slot of the spindle.

Through the slot, I can see the upper narrow end of the spindle arbor
shank going into the spindle as described. But I can't figure out how to
"lock" it into place.

Am I supposed to push harder? What exactly locks this into place?

Would anyone out there know how to do this with the Tradesman? Thanks!

Jack