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Brian builds a Corliss

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  • #91
    Shoulder bolts that size you probably make. You can get 2-56, 4-40, M1.5, M2, M3 fairly easily, but #5, no.
    CNC machines only go through the motions.

    Ideas expressed may be mine, or from anyone else in the universe.
    Not responsible for clerical errors. Or those made by lay people either.
    Number formats and units may be chosen at random depending on what day it is.
    I reserve the right to use a number system with any integer base without prior notice.
    Generalizations are understood to be "often" true, but not true in every case.

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    • #92
      Jerry---Have you got a link to 1/8" shoulder bolts with a #4-40 thread?
      Brian Rupnow
      Design engineer
      Barrie, Ontario, Canada

      Comment


      • #93
        Originally posted by J Tiers View Post
        Shoulder bolts that size you probably make. You can get 2-56, 4-40, M1.5, M2, M3 fairly easily, but #5, no.
        McMaster has #5 shoulder bolts listed.

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        • #94
          I think this engine would look much better if really small screws were used for much of the assembly. Compare the model to this Corliss engine:

          Click image for larger version

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          https://www.thehenryford.org/collect...lide=gs-198756

          Here is the most famous, and largest, Corliss engine:

          https://newsm.org/steam-e/corliss-centennial-engine/

          Other Corliss engines:

          https://newsm.org/steam/corliss-steam-engine-1892/

          Here is a site which offers a plastic model kit and a nice GIF showing valve and piston operation:
          https://mechanicalgifs.com/corliss-steam-engine

          Click image for larger version

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          http://pauleschoen.com/pix/PM08_P76_P54.png
          Paul , P S Technology, Inc. and MrTibbs
          USA Maryland 21030

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          • #95
            A 1/8 bolt would be #5-40 or #5-44.
            Kansas City area

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            • #96
              Originally posted by PStechPaul View Post
              . . .Compare the model to this Corliss engine:
              Paul,

              Your research into the Corliss is just what we needed to understand this complex engine. I had seen that lithograph of the Centennial Engine at the 1876 exposition, but I did not know it was a Corliss. Nor did I know that the Corliss always operates at constant steam pressure, changing the valve's duration to match load conditions.

              The acrylic model is a beaut. I don't see much resemblance to Brian's plan (which has a "wrist plate" with four arms connected to the valves).

              Allan Ostling

              Phoenix, Arizona

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              • #97
                Originally posted by aostling View Post

                The acrylic model is a beaut. I don't see much resemblance to Brian's plan (which has a "wrist plate" with four arms connected to the valves).
                I don't know if there were different versions of the Corliss valve gear or not, but what Brian is making is pretty close to the original Corliss engine running at the New England Wireless and Steam Museum in CT. What both versions leave out (likely for the sake of simplicity) is that the rotary valves have mechanisms on them so that they can vary the time the valves are open independently and are designed to snap shut quickly. The other big improvement was that the incoming steam and the cooler exhaust do not travel through the same passages going through the valves. There is lots of technical nuance involved that I don't pretend to understand, but collectively this was apparently a big boost to engine efficiency.


                This is an interesting technical demo of the Corliss valve gear from the New England Wireless and Steam Museum that explains it in some detail. It's a fascinating device:
                https://www.youtube.com/watch?v=4pCSke22zHE&t=2s

                If you look around their youtube channel or website site, you will find a number of other videos about that particular engine, which is believed to be the only original Corliss company Corliss engine that is still able to run under steam power. They fire it up for demos at least once per year. I have been there for that, it's an impressive thing to see.

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                • #98
                  Oxford--Thank you. I never even thought about McMaster. They have exactly what I want. They will not sell to individual Canadian accounts but I have a friend with a design and build company who can order them from me.----------Paul--I have a love affair with socket head cap-screws. I like them more than any other fastener. If I was going for authenticity then I would go for hex head bolts, but I'm not. I'm doing a Corliss purely because it has a different valve system than anything have made before.-----------Brian---
                  Last edited by brian Rupnow; 02-27-2022, 09:14 PM.
                  Brian Rupnow
                  Design engineer
                  Barrie, Ontario, Canada

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                  • #99
                    Originally posted by oxford View Post

                    McMaster has #5 shoulder bolts listed.
                    They seem to only have them in stainless. Not in standard alloy. That is the first place I looked, but I looked in ordinary alloy steel.
                    CNC machines only go through the motions.

                    Ideas expressed may be mine, or from anyone else in the universe.
                    Not responsible for clerical errors. Or those made by lay people either.
                    Number formats and units may be chosen at random depending on what day it is.
                    I reserve the right to use a number system with any integer base without prior notice.
                    Generalizations are understood to be "often" true, but not true in every case.

                    Comment


                    • Originally posted by J Tiers View Post

                      They seem to only have them in stainless. Not in standard alloy. That is the first place I looked, but I looked in ordinary alloy steel.
                      Yes I saw that. Beggars can’t be choosers I guess.

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                      • I ordered the shoulder bolts that I need from McMaster Carr thru my friend who runs a local design/build shop this morning. I took the lathe to Toronto and dropped it off at Busy Bee to be repaired. They will fix it and ship it up to their store outlet in Barrie free of charge and I will pick it up there. I have enough parts to make that aren't lathe dependent to keep me occupied in the meanwhile.
                        Brian Rupnow
                        Design engineer
                        Barrie, Ontario, Canada

                        Comment


                        • So one could design a steam engine today that would be greatly simplified and even better efficiency with electrically controlled valves, encoder, and a microprocessor. The majority of the engineering spent on the electrically controlled valves for reliability.

                          Comment


                          • Originally posted by RB211 View Post
                            So one could design a steam engine today that would be greatly simplified and even better efficiency with electrically controlled valves, encoder, and a microprocessor.
                            And what would the fun of that be?

                            Comment


                            • Originally posted by lbender View Post

                              And what would the fun of that be?
                              I’m glad you asked.
                              What’s the fun building a model of an old obsolete design? How is that fun?
                              Maybe the fun is subjective! Maybe the fun is in the engineering of something new and different? Maybe the fun is achieving something greater than the engineers of the past could achieve in their time? Maybe the fun is really more centered around the electrically driven valves than the engine itself?
                              Maybe the fun is recreating the past. It’s subjective. You just see 95% recreating the past though, rarely a hobbyist trying to beat the engineers of the past at their own game. It’s called hobby engineering, right?

                              Comment


                              • Originally posted by RB211 View Post
                                I’m glad you asked.
                                What’s the fun building a model of an old obsolete design? How is that fun?
                                Maybe the fun is subjective! Maybe the fun is in the engineering of something new and different? Maybe the fun is achieving something greater than the engineers of the past could achieve in their time? Maybe the fun is really more centered around the electrically driven valves than the engine itself?
                                Maybe the fun is recreating the past. It’s subjective. You just see 95% recreating the past though, rarely a hobbyist trying to beat the engineers of the past at their own game. It’s called hobby engineering, right?
                                So when will you be starting a build thread?

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