David:
I extended the keyway, but I had a defective (cracked) disk of which I was unaware. By the time I figured it out, the thing has wallowed out the keyway. ANyway, I was able to put on another one and clean it up enough to make it work. It fits nicely into my head stock now.
I don’t think I want to post an “after” picture of this near disaster. 
Thanks!
Tom