Maybe this will help.

Here is a link that might be useful: Craftsman router

Thanks Canguy, but I don't still have a clue. What do you see when you look at the diagram? I'm guessing that if I can determine a way to disassemble the ring, or maybe a twist with the strap wrench set to kill may help. I went as far as pulling the end cap out w/ the brushes and armature. In the words of Sargent Schultz- I see nothing- nothing!

This diagram shows what look like threads on the motor housing. Maybe it screws off once the motor wires are disconnected.

Here is a link that might be useful: Craftsman router

Thought that I would post an update thinking at some point there would be a person seeking to know the same thing. Tried everything I could think of. I won't even bother to list. In the end, I destroyed it piece by piece to find the solution. The collar distorted enough to where it would never come off the motor housing. Didn't even seem to have been run too hot. Correct fix for this problem: Toss it. Better solution: Don't buy krap.
But on the bright side I now have a motor w/ a 1/4 collect on the end...

There is a lot of this type of merchandise out there.
They are built for easy, economic assembly with no
regard for later repairs. Don't feel bad, even if you
got it apart, the repair parts are probably not available.
But I'm like you, as I will destroy something if it isn't
made to take apart, just to see what the problem was.
The last thing I did along this line was cut open a
sealed refrigerator compressor to see why the motor
inside had quit, (yes, the refrigerant was evacuated
per EPA guidelines ;~)

So the next odd question: What do I do with it now? I re-assembled the motor, hooked up the switch and light and it sings once again @ 25,000rpms. I have a die grinder. Make a little fixed grinder for something?

Just tuck in up in the rafters. You'll eventually find
a use for it. But, utilize the 'Five Year Rule', which
means that if you don't use it in 5 years then toss it.
But also remember, the day after you toss it, you will
need it.