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.


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