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Sparey Diesel Crankshaft

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Sparey Diesel Crankshaft

Home › Forums › I/C Engines › Sparey Diesel Crankshaft

Viewing 7 posts - 1 through 7 (of 7 total)
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  • 16 August 2024 at 13:15 #747359
    Clive Brown 1
    Participant
      @clivebrown1

      I’m making the 5cc Sparey Diesel to Hemingway’s plans. The crankshaft is specified as from 1.25″ dia steel bar. In particular, the overhung crank-pin looks to be an awkward machining operation. I’m wondering if a press-fit or loctite assembly might be OK. Perhaps also even for the crank web onto the shaft itself.

      Any thoughts or experience of such construction?

      crankshaft

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      16 August 2024 at 13:25 #747361
      JasonB
      Moderator
        @jasonb

        machining is not too hard, you can either use  a keats type angle plate or bore  a block of aluminium to clamp the shaft in then the block can be held in the 4 Jaw. If going for an integral pin then you can mill a lot of the waste away to leave a small square that can be easily turned and a clean up facing cut to the web.

        HPIM1458

        IMAG0684

        IMAG0694

        I have also done pressed in silver steel pins, a hand reamer not run all the way through will leave a taper that grips the pin more the further it is pressed in.

        16 August 2024 at 13:35 #747363
        Clive Brown 1
        Participant
          @clivebrown1

          Thanks for such a quick response JasonB. How do you manage such relevant pictures at a moments notice? My Keats angle plate is a fairly big thing and doesn’t really appeal for this job. The aluminium block looks better to me, but the shaft will need tight clamping. i think that might be the way to go though.

          16 August 2024 at 16:16 #747369
          bernard towers
          Participant
            @bernardtowers37738

            When I made mine as all my others I do them all in one as it is imperative that the pin is perfectly in line with the crankIMG_7937

            16 August 2024 at 16:22 #747375
            larry phelan 1
            Participant
              @larryphelan1

              Clive,

              You wonder how Jason manages to respond so quickly ?

              I suspect he must have done these things before !!

              16 August 2024 at 16:28 #747379
              Neil Wyatt
              Moderator
                @neilwyatt

                Jason beat me to it.

                It’s so easy to do it with the offset clamp, even I managed to do it!

                Unfortunately, it’s still 50% unfinished since this photo taken in 2003. Oh heck, that’s 21 years ago…

                😧

                Neil

                Raw Materials

                16 August 2024 at 17:07 #747393
                JasonB
                Moderator
                  @jasonb

                  That photo looks 100% unfinished too me😊

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