Looks like you have a 1/2" collet and the nut that goes with it to be

threaded on the shaft, shown in photo you call spare chuck.


Except that it won't go onto the shaft. I've tried! The collet sticks
out on the side with the threads and will not go into the shaft.

If they show an exploded view of the router in the parts manual, it
should help you.


Doesn't have one. That would make it too easy. ;-)

Thanks for your reply.