One of the best ideas I ever heard about making E-shafts is hydro
forming. That is where a hollow steel tube is put in a mold and
tremendous pressure is applied to form the lobes.  I suspect the the
 tube is heated to high temperature first. I think a lot of steel car
 and truck tubular frames are made that way. Stuff is made in minutes
 not counting the heating time.

Paul Lamar

You can not heat it much as the oil/water would boil or carbonized.
Metallurgy and post heat treat I think. Body panels are also made
this way in steel or aluminium. For this a mold is installed a a
sheet is slipped in. An outer piece comes down and clamps the sheet.
 Then high pressure liquid is pumped in which forms the sheet against
 the mold or form. The the liquid is pumped out.

Dale Davies


I would imagine you would need to start with 0.5" or 0.625" wall
tube to allow for the thinning during the stretching for the rotor
bearings and then allow a bit for final machine to dimension and
then heat treat and nitriding. Dale Davies

What range of pressure are we talking about here?

Paul Lamar


I've done a bit of research into hydro forming.  I've been
considering using it to form wing ribs.  I've seen in the literature
 pressures up to 1000 atmospheres used for forming sheet aluminum.
I'm not sure what the pressures would be for forming steel tubing.
Maybe twice that amount? There's quite a bit of stuff on YouTube
about the subject.

I've looked a bit for a source for a high pressure pump that is
capable of generating 1000 ATM but so far I've come up dry.  Even
hydraulic jacks don't use any where near that kind of pressure.
Maybe a hydraulic multiplier pump could be built where a 4" diameter
piston drives a 1" diameter shaft into a cylinder displacing the
fluid inside at 16/1 pressure ratio.  That should easily get you 1000
ATM.

I just calculated that a 20 ton jack, with a 1.5" dia shaft, should
be able to create 22,675 PSI using that method.

I've seen several videos of people using a pressure washer to inflate
an envelope made by welding the edges of two sheets of steel
together. That might be a way of creating a poorly formed tank in a
pinch but it's practically useless for anything else.

Mark LaPierre


JFI, Haliburton Hydro Fracturing works in ranges up around 20,000
PSI, they hire out for a price. My knowledge of it is years old, but
 they sure can deliver PSI. I think if you set up the right equipment
 they could easily provide the PSI for any job.

George F. Curtis Jr.


Frac equipment would be a bit overkill, it is designed to produce
those pressures w/ huge volume as well. We're talking trailers which
have a several thousand hp motor/pump combo. I've built a few
smaller units (IIRC 1500hp w/ 2000psi up to 1500L/min) and it'd not
be economical to use them for this, unless it was a grand scale of
production work.

That being said, another source of super high pressure water would
be a waterjet pump. We had a waterjet at my old job, it could produce
up to 60Ksi but at only 3-4gpm. Hourly costs would be much less.

There would be untold other teething problems in proving out a hydro
formed shaft, but someone like Mazda could probably afford to do it.

I recall seeing a YouTube video of a guy building a tuned pipe using
the pressure washer method, but he was inflating "gauge thickness"
metal.

Fwiw Jarrett Johnson

Seems to work for the 2 stroke guys pretty well...
http://youtu.be/VV4eGaHG0bM

Dan Gorsline.


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