I know talk is cheap, but every time I look at a 20-b e-shaft
I can't help but thing that it's a no-brainer to cut on any decent
CNC lathe.  I'm sure there's a bit more to it than turning a hunk
of steel and hardening the crap out of it.  Anyone have any
in site into what's *really* involved in making a 3 rotor e-shaft?  I
know a few others have done it.

Thanks,
Bob

I think you are pretty much right.
I think you need to grind and polish it after it is turned
and heat treated.
--  Paul Lamar ...No rotor no motor.

Bob,
Well there's selecting the right material in the first instance as different
heat treatments for different materials have different outcomes.
Of course there's the core toughening characteristics required as  well as
the surface hardness. You would need to know those parameters to  advise the
heat treaters.

Yes CNC would be good, but you need to grind before you heat treat, so
selection of heat treatment and therefore material is important as  you don't
want too much distortion. A final polish will be required. CNC  will give
the most accurate eccentric off-set and the centre oil line needs  to be
accurately drilled.
That's only the one rotor and 2 rotor, I know nothing about the 3  rotor, so
the position of the 3 rd.  lobe and joining the two pieces, is  probably
another story.
So apart from those things your probably right - piece of cake!

Oh yeh then theirs the balancing - probably better to buy one, no  matter
what the cost!
George (down under)

Grind AFTER heat treat.

Paul Lamar

This is a good chance for me to expose my ignorance.  The e-shaft has
one center through  the main shaft and another center which is the
center of the eccentrics.   How would it be set up in the lathe?   Jerry

I don't really know how it is done.
I think to do it on an NC lathe it takes a one step up machine called
a four or five axis lathe. Either that or something like a
special clamp with an offset center that goes in a regular
NC lathe chuck. The world has been doing this with crankshafts
for 100 years.

Paul Lamar ...No rotor no motor.

ECI had a shop at my airport, TTD.  i don't know much about machining, but
was impressed at the crankshaft grinder.  they chucked up the crankshaft to
rotate about the rod ends and then ground it with these 2' diameter grinding
& polishing wheels.  a very specialized, expensive piece of equipment.  the
whole job took but an hour max.

for my 20B, i just called bruce turrentine and ordered one.

Kevin Lane

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