>> 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.


I don't see how making an e-shaft is any different from making a
camshaft.  But possibly easier because the eccentric is round..

I kind of don't think CNC buys you much - the shape doesn't seem that
complex.  I see it kind of like duplicating a key for a tumbler lock
(kinda).  The machine allows you to chuck the blank and the pattern.
The chuck/blank rotates slowly, the grinding stone quickly.  The
grinding stones position is determined by a stylus resting on the
pattern.  The pattern can be made up from non-structural, easy to grind
material - in pieces.


Matt-


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