> <Snip>

 > > > > Paul - I am sure that I could turn the "bowl" for the bell housing
 on my
 > > > > lathe
 > > > > using wood as the pattern material. The other parts could then be
 > > > > pieced on rather easily. With a bit of draft and planning it looks
 like
 > > > > it could be a simple cope and drag sand casting with no fancy
 > > > > coring. I made aluminum cast wheels for a sports car project about
 > > > > 25 years ago - Vance J
 > > >
 > > > That is the hard way. It only takes me a couple of hours to make
 > > > a pattern. Not only that it does it while I sleep :)
 > > >
 > > > The big thing is the .010 accuracy possible with 3D. You will play
 > > > hell turning a bowl only .2 inches thick with a constant wall
 > > > thickness by hand. The entire lower half of the pattern is
 > > > a box. Mainly due to the necessity of mounting the starter.
 > > > then you have the vertical walls on each side needed for the
 > > > motor mount brackets. Not to mention all the drafts needed on
 > > > all the interior reinforcing webs and all the walls. Then you
 > > > have fillets on all the junctions between interior webs and
 > > > the outer walls. It could take a month of hard work.
 > > >
 > > > Hand made casting patterns in the age of Rhino and 3D machines
 > > > are ancient history.
 > > >
 > > > Paul Lamar

 > david mccandless wrote:
 > >
 > > Paul, I'm not getting a picture of the bell housing rhino, could you
 > > send it again please? (Dr Wankel at NSU did it in millimeters, Yamamoto
 > > at Mazda did it in millimeters, What's this inches mumbo jumbo? Yeah, I
 > > know, the shuttle is in inches! Luv your work Paul! Dave McC
 >
 > I am too old to change Dave :)
 >
 > Paul Lamar

 I'm with Dave.  I may be a mechanical engineer, but I'm too staid in my
 T-square and woodshop ways to make the switch to computers and 3D machines.
 Besides, I don't have *those* in my basement!

 Since I have more time than $$$, some pine and a wood lathe will win out
 every time.  And yes, I can hand turn a cylinder or cone to a 0.01" diameter
 tolerance.  After roughing with a skew chisel, I use a finely set plane to
 smooth the contour to within ~0.03" oversized, and sand paper for the rest.
 Works great (except on @*#&&*# endgrain... that doesn't sand evenly!).

 Tom Kendall

I think Dave was talking about the metric system verses the inch system Tom.
Cones or cylinder are one thing but when you get beyond those that's where
the computer really pays off.

Tom you really need to try high density foam. Works like wood but
there is no grain.

http://www.freemansupply.com/PolyShapeIIPolyure.htm

OK Tom you do the pattern and work a deal with Tracy. It will
save him some machining time and a bunch of long 1/4 bolts not
to mention a few pounds. I will help with initial financing,
act as liaison with the foundry and provide some marketing
help through the news letter.

If it looks a bit like the Ross is should as Ross got it
pretty much right. All walls are .2 inch except where
necessary for bearing mounts.

BTW it loads the gear set through the back just like a car
transmission. It can be retrofitted with Tracy gear sets already
out there if someone would like to upgrade. Me for one.

Paul Lamar

The ultimate bell housing will live up to its name I think.  Clearly
it is best of all possible worlds.   And it will fit on the universal
engine mount fixture without a hitch.  Really great work Paul.

  Looking forward,  I hope to have the prototype PPort housing with
throttle body done by the time the newsletter is back in action.

Seasons greetings and well wishes to all the participants of this
forum.    Jerry

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