WHY? Because it is the power supply for the newly obtained Trek Lime Lite.
It is an automatic (electric yank) shifting three speed Shimano hub,
with front dynamo, (magneto, really), pretty clearly related to other Shimano hub dynos.

WHAT: I am taking it down soley to learn how it works.
I have a background in watch repair and antique auto restoration and fine piano tuning;
I have pretty good, basic mechanical skills/intuition, but NO experience here.

QUESTION: How, or do I even UNSCREW this large nut?

IF SO, if it is unscrew-able so that I can withdraw the stator, is it R.H. thread?
I'm modding an old, small bench vice to get a good, proper grip on the 37mm aluminum "nut"
on the "electrical side"; it seems that this must be unscrewed, cover integral.

But my experience here is nil, and my eyesight now very poor.

Help? WHICH WAY, if either, do I turn. IF I break it, I just go buy a new wheel, my loss.
I am doing this to learn just how these things are built: pretty darned well, imo, for a basic magneto!
----

Here's link to the relevant "Reid Breaks Everything!!" portion of the thread:
taking down the Shimano dyno:
http://www.endless-sphere.com/forums...174112#p174112
(lots of detailed pictures, then the pictures cease
when I get to the impass of the moment:
that big nut molded, apparently, into the cover.

I want to pull out that stator for photography.
The thing is very much related to the Model T magneto system of 1908,
just up to date, and for this cool, auto-shifting super-basic cruiser bike,
instead of for old time Model T ignition and auto headlighting.