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Building the Trevithick Engine

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  • I first read "Trustee from the "Toolroom" in the early 1960's, in one of my fathers " Readers Digest Condensed Books". I immediately fell in love with the story. As an adult, I bought the book, and read thru the full length story, and fell in love again.--I spent one night in a Salvation Army hostel in Thunder Bay, returning from an ill fated trip to Calgary, ran out of money, car broke down, Jeez, it was like a country song. I still remember being told by the attendant, sleep with your boots on and tie the laces together in hard knots, because boots are one of the most stolen things around here. I do have a very good idea of how lucky I am, and thank you for your good wishes.--Brian
    Brian Rupnow
    Design engineer
    Barrie, Ontario, Canada

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    • Before I can make any more progress, I have to back up a little and repair a problem. The elbows which feed air to my 4 way rotary valve are interfering with the inside of the "boiler" pipe. I have designed a new "close fit" elbow, and will be machining and installing a couple of them today, so I can start working on the business end of my Trevithick.
      Brian Rupnow
      Design engineer
      Barrie, Ontario, Canada

      Comment


      • Brian - Neville Shute the author of Trustee from the Toolroom is one of my favorite authors. I believe I own a copy of every book he wrote and have read them all. Some more than once including Trustee from the tool room. I have only one "complaint" about his books - the stories are so good I have stayed up half the night a few times to finish his book because I just could not put it down. So he caused me to loose same sleep from time to time.
        Larry - west coast of Canada

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        • Cuttings--I read a lot. I find that as my old authors die off, there are fewer and fewer authors who write well enough to replace them. There is something very sad about that. This is the new "clearance style" 90 degree elbows finished. You will notice a small hole in the top of the right hand elbow. I didn't plan that. A dab of J.B. Weld will fix it. Tomorrow, assuming everything fits properly, it's almost time to turn my hand to the mechanism that operates the 4 way valve.
          Brian Rupnow
          Design engineer
          Barrie, Ontario, Canada

          Comment


          • Today was a day for fettling and fitting. The new elbows on the 4 way valve gave me the clearance I needed, so I was able to bolt the end with cylinder attached to the boiler. I routed the air supply hose from the 4 way valve to the hose barb in the back plate, and routed the exhaust thru the backplate and into the smoke stack. The only new part machined today is the arm attached to the bronze gear which sets on the flywheel shaft. I'm hoping that my local nut and bolt store has 3/16" shoulder bolts, which will attach the "connecting rods" to the new arm and to the flywheel. I'm thinking that the boiler would look a lot better with a flange at each end. I may buy some material to add a flange to each end of the the boiler.
            Brian Rupnow
            Design engineer
            Barrie, Ontario, Canada

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            • Well Rats!!! Nobody in Barrie carries 3/16" shoulder bolts. I went a head and made my own, now I can connect my connecting rods to the flywheel and crank arm.
              Brian Rupnow
              Design engineer
              Barrie, Ontario, Canada

              Comment


              • If I had some 1/8" rod bent and threaded, I'd have connecting rods finished. The four brass ends are shown in place in this picture. I've got so much junk on top of my "assembly table" hat it's hard to see. Tomorrow I'll make and install connecting rods.
                Brian Rupnow
                Design engineer
                Barrie, Ontario, Canada

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                • It's time for a change in my game plan. I had originally planned on using 1/8" diameter cold rolled steel round-bar with soldered brass ends for connecting rods. Tried that yesterday, but found that 1/8" is far too skinny and bendable. not going to work. Went out today and spent some of the Rupnow fortune on spherical rod ends. The con-rod diameter will now match the o.d. of the female rod ends.
                  Brian Rupnow
                  Design engineer
                  Barrie, Ontario, Canada

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                  • Here we have the "heavy con-rod" on the non gear side, with a spherical rod end on each end. As things work out, the con rod on this side doesn't really need an offset, which is fine with me. Tomorrow I will work on the gear side con rod, which definitely will have an offset in it to clear the hub on the 108 tooth gear.
                    Brian Rupnow
                    Design engineer
                    Barrie, Ontario, Canada

                    Comment


                    • Yikes!!

                      Those are huge???

                      Sid

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                      • Yes, they are huge. Right now everything is aimed at getting the engine to a stage where it runs. Once the engine runs, They may get replaced by smaller rods. I first tried to use a bent 1/8" diameter steel rod with brass ends, but it was far to flexible. Nobody in Barrie had 3/16" rod ends, so I was stuck with using 1/4" rod ends, and the nearest I could get to the 12mm diameter female rod end was 1/2" round aluminum.
                        Brian Rupnow
                        Design engineer
                        Barrie, Ontario, Canada

                        Comment


                        • Brian, don't know if you have any hobby shops locally but the RC airplane and car folks use tiny rod ends all the time as well as threaded music wire for pushrods. There is quite a variety of hardware like this used in the RC hobbies.

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                          • Couple of things I should mention.-- That new con-rod is way too large in diameter, but it won't deflect under load, and once the engine is running it will be replaced with a smaller diameter piece.--And--I picked up a piece of material today large enough to create "flanges" for the ends of the boiler. I think that if these boiler "flanges" are added they will do much to make this model look more like the original Trevithick engine. It's a bit difficult to imagine with the 3D model being more colors than the rainbow, but I think it will look better.
                            Brian Rupnow
                            Design engineer
                            Barrie, Ontario, Canada

                            Comment


                            • I don't always agree with Sid, but Sid, when you're right, you're right. I couldn't stand how big and clunky a 1/2" diameter con rod looked. Today I made new con rods from 5/16" diameter cold rolled steel to replace the first one which was 1/2" diameter aluminum. Everything looks a lot more proportional now. Video to follow when my camera battery is charged.
                              Brian Rupnow
                              Design engineer
                              Barrie, Ontario, Canada

                              Comment


                              • Well, now we’re making some progress!
                                Looks better. I’d still get rid of the big ass rod ends. Although, the spherical aspect probably helps with miss-alignment Issues.
                                if your looking for something that will work, your there. If your looking to look a little closer to authentic, better design some new ends.

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