Two Cylinder Mill Engine



  • Chuck Doan send my MANY photos of prototype engines with the crossover belt. Did you work on these for years?

  • I did a ton of research when building mine but never saw a belt threaded like this. My curiosity has been raised. I’d sure like to get a glimpse of those pics Chuck shared with you.
    Can you post a few of them?
  • Bill, of course. Being my week, I probably got this wrong as well. I based my weathering on these photos but did not want my engine quite this grungy.

  • What does the G. belt drive do?
  • I also sloped my steam inlet tube based on my knowledge of house heating steam boilers. Might be wrong as well? Hard to find anyone that REALLY knows anything about these. Lots of experts on FB these days. As Buk said: "God realized there were a lot more poets than good poems."
  • Finished.

  • A detail.

  • Other side:

  • EricMG said:

    What does the G. belt drive do?

    The governor belt drives the governor.
    The governor controls and regulates the RPM of the engine.
    The governor uses centrifugal force to open/close a throttle valve and thus
    controls the RPM of the engine and keeps it constant.

    The engine that you have shown the three pictures of has probably had the
    twist put into the belt as a maintenance measure.

    Twisting a belt is generally done to reverse the rotational direction of
    the second pulley. However...

    As the govenor can run in either direction the twist was possibly put in
    to shorten a stretched belt and/or provide more contact with the pulleys
    thus reducing slippage.
    Or, the belt was 'wandering' off the pulley, putting a twist in the belt
    prevents this and helps keep a belt in-line.

    Another reason for twisting a belt is to counteract a crosswind
    interfering with the belt. Usually done on exterior equipment. As the
    engine shown is inside a sawmill(?) this was most likely not the reason for
    the twist.


  • This is why I love the SierraWest forum! Thanks for the info Karl.
    Never made the connection that the twist reverses the rotation of the other pulley until just now.

    I agree with MuddyCreek: it seems like the belt would make contact with itself at the location of the twist. But perhaps speed causes a little separation? Or maybe the return pulley is offset from the driver.
  • edited December 2018
    Talked to my buddy Mitch. He worked the north Maine woods for 20 years. He said they 180ed those pulleys 75% off the time. Even new belts ones. There you have it. Thank you for the supportive comments on my model. You guys are SO supportive.
  • As Paul Harvey might say, "... and now you know the rest of the story." Great model photos from Eric and operating engines by Chuck Doan, great support by the crew here on the forum and incredible info about the "governor belt" from Karl A. This turned into a very informative build. Thanks for beginning the post Eric.

    Later, Dave S Tucson, AZ.
  • It did end wonderfully. Thanks ALL!
  • Very well done Eric. Even if I don't quiet understand how such an engine works, it looks impressive, dirty, greasy, mean just like an old Harley Davidson... :wink:
  • On that last pic, the grease looks awesome and has just the right sheen to look real. Concrete base is splendid...
  • Outstanding work Eric. It looks so grimy and greasy. Weathering has been done very well
  • A friend of mine is into steam engines...I will ask him for clarification.....Most driven belts I've seen on engines tend to not cross....the tendency seems it would rub and then jump the also has to do with the needed rotation of the driven pulley....
  • Eric. Taking your time and getting it right was well worth the effort. ........Carl........
  • edited December 2018
    Thanks for the generous comments, lads. Funny to put so much into such a small item, but I always liked these engines and now I actually understand how they work. Thanks, Karl for the explanation.

    And Merry Christmas! Hope yours is full of cheer and models.
  • edited December 2018
    Mainers are an independent people. We can make our own.

  • Wonderful piece Eric!
  • Nice work!
  • how did you do the grease? masterful weathering!
  • Chuck Doan passed me his secret. Let me check with Chuck if sharing is okay with him. I'm sure it is. Worked well of course. Lee Turner is my go to guy for most questions. He seems to know everything, even how to wire the antenna on a 1/48th DC-3 that I just finished. I built it for the memory of my father. My father was a plane guy winning the Canadian Nationals three times. He created a working radio controlled airplane in 1946. Still have is original equipment, all handmade of course.

    Happy New Year! To great models!

    Mill engine
  • Great looking modeling !!!
  • Eric,

    An amazing story accompanied by some amazing modelling.

    Looking forward to more great projects, photos and posts in the New Year.

    Later, Dave S Tucson, AZ
  • Like the picnic tables
  • Check's secret. Black paint with fine grit depending on scale. THEN use gloss medium over the top.

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