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Thumper---A new 1 3/8" bore i.c. engine

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  • Pretty husky looking crankshaft. Good job Brian.
    Larry - west coast of Canada

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    • I just tried to upload a video to YouTube.---It loads to about 34% and just hangs there. Anybody know if YouTube is having a problem?
      Brian Rupnow
      Design engineer
      Barrie, Ontario, Canada

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      • Originally posted by brian Rupnow View Post
        I just tried to upload a video to YouTube.---It loads to about 34% and just hangs there. Anybody know if YouTube is having a problem?
        It was earlier, very very slow to load. a full minute just to open. It was better later.
        CNC machines only go through the motions

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        • YouTube still won't upload a video. Maybe because there are 300,000,000 people staying home and playing on the internet. This morning I test fitted the rings into the cylinder. The rings have a stepped gap, however when I had a ring pressed into the cylinder and held it up to a bright light, there was still clearance for the ring gap to close a little bit more if it expands with heat. I was satisfied with the fit of both rings. I set my piston up in the lathe 3 jaw chuck and very carefully opened up the 0.086" wide gap to about 0.095" to accept the 0.094 thick rings. Any time I cut a groove in aluminum, it raises a shoulder on each side of the groove. Not much of a shoulder, but enough to keep an already tight fitting piston from sliding into the cylinder. Knowing that, and knowing that a few people were alarmed at the thought of a tight fitting aluminum piston in a cast iron cylinder, I walked a piece of 220 grit garnet paper back and forth on the piston to knock down the shoulders and take about 0.0005" off the overall piston diameter. the rings went onto the pistons with no problem. I had the cylinder off the engine, so set it up in my 3 jaw and machined a 15 degree "lead" taper into the bottom to aid in installing the rings. everything went together fine. In about 15 minutes I'm going to make a head gasket and install it, and then the engine will be finished except for the flywheels.
          Brian Rupnow
          Design engineer
          Barrie, Ontario, Canada

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          • The engine is finished---except for flywheels. There may a significant time span before I get the flywheels finished. I am now turning my attention to the flywheels, which will very probably be fabricated with my new TIG welder. Thank you, to those who have followed this thread, which was started 32 days ago.
            Brian Rupnow
            Design engineer
            Barrie, Ontario, Canada

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            • My TIG situation is mostly sorted out, and now I can begin work on the flywheels. I woke up this morning thinking about how to fixture the hubs of the flywheels to cut the 45 degree slots in them. Sometimes if I model what I am thinking about, it helps to clarify things. It looks to me that if I make the yellow fixture, I can hold it in my vice and just crank the mill table back and forth in the X axis to cut the slots. I will have to drill a set of holes in the face of the hubs to register them on the yellow fixture so that they don't move while being cut.
              Last edited by brian Rupnow; 04-02-2020, 06:21 PM.
              Brian Rupnow
              Design engineer
              Barrie, Ontario, Canada

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              • Every time I read Brian's engine posts, I am reminded that I am not an Engineer's backside! What amazing skills!

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                • And that, my friends, is slicker than whale poop!! Here you see one of the finished hubs by itself, and with a nice blade array using a bunch of my parallels. I just wish I had a 1/8" wide slitting sawblade. This was made using a 1/16" saw blade, but I had to go around once to make the slots 1/16", then around once with the blade offset 1/32" then again with the sawblade offset the other way by 1/32". This was far less work than I anticipated. I will make the second hub tomorrow.

                  Brian Rupnow
                  Design engineer
                  Barrie, Ontario, Canada

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                  • A 1/8" slitter? you got a 1" or 7/8" arbor? I will look for one, I got a box of old horizontal mill cutters.
                    PM me a mailing address

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                    • Thanks for your kind offer, but the shipping would cost more than the cutter.---Brian
                      Brian Rupnow
                      Design engineer
                      Barrie, Ontario, Canada

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                      • This morning I put on my mask ,Purelled my hands, and drove to my metal suppliers who had set my material outside their door. Collected my material, Purelled my hands again, wiped down my trucks steering wheel with antiseptic wipes, and drove home again. Got home, washed my hands for 30 seconds with warm water and dishsoap. My hands have never been this clean. I look goofy wearing a mask. The 1" x 1/8" cold rolled flatbar is exactly what I asked for. The tube is 6" o.d. but the wall is only 7/16", not the 9/16" that I had wanted, but it will do. I could die of old age before my bandsaw would cut thru that pipe, so I will part off "rings" of material 3/4" long. I think I will weld a flatbar across one end with a hole for a live center and hold the other end in my lathe chuck with reversed jaws. You can't cut all the way thru in the lathe or bad things will happen. DAMHIKT. You can however, cut almost thru and then complete the cut on the bandsaw. This was the last material I will require to build this engine, and by the time I buy a set of ignition points and a condenser, it's going to get very close to the $200 mark. The steady-rest is which came with my lathe is way too small to use--looks like it will only open up enough to take 3" diameter stock.
                        Brian Rupnow
                        Design engineer
                        Barrie, Ontario, Canada

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                        • Brian - There is drawing in the book I have for a steam donkey to make an internal steady rest that is held in the tail stock of the lathe. Basically it is a wheel that fits inside the tubing with a center hole bored to pivot on a mandrel that is held in the tail stock chuck. If you want more details just yell.
                          Larry - west coast of Canada

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                          • Thank you Cuttings. I'm not totally clear how I'm going to go about doing this yet. I (think) that a metal bar welded across one end of the pipe, and center drilled to accept my live tailstock center will do the job. I want to be very careful with his, as I have been chased around my little shop before by a pipe coming out of the lathe, and it was very exciting. Now is not a good time for a visit to the hospital.
                            Brian Rupnow
                            Design engineer
                            Barrie, Ontario, Canada

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                            • beautiful work as always Brian. I especially like the side plates for some reason..

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                              • Cuttings if you have any pictures or drawings of the device I would be interested.
                                Thanks
                                olf20 / Bob

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