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Starting new Steam Engine, Murphy is helping.

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  • Starting new Steam Engine, Murphy is helping.

    Starting PM Research No. 5 model today (coke bottle style) Last year was my first attempt, making the 1880 steam drill. While it looks and works ok, I don't think there is a single part on it that I didn't screw up somehow. Sort of like chasing a lie, each mistake requires an appropriate 'adjustment' to the next piece. So for this model, my goal was to make it closer to spec.

    Started on the cylinder last night, a nice little bronze casting. Got the bore out to .625" then got a nice cross hatch at .6255 (approx) Faced off the inboard side of cylinder to the mark, no problem. Turning outer flange was tight quarters. In an effort to avoid the valve outlet flange, I started in too far, and flange O.D. ended up 15 thou' under spec on first cut.

    Unshipped part, flipped her around (using a bigger mandrel to center) to machine to length, then snagged the casting sprue when I brought the tool in too fast and ripped her right out of the 4 jaw, with enough force to bend the casting. I know because the 5/8" rod would not go back through the hole. Also ripped out a fair divot of metal, which (luckily) machined away when I faced that flange to length. Sooo, I'm over size on the bore now with an undersized flange. Cylinder length and one flange are to spec. Batting 500. NOT BAD!!! Ha! I'd be embarrassed if I had any sense.
    I'm here hoping to advancify my smartitude.

  • #2
    I have found from time to time Murphy sticks his big nose into things I am working on. But as it has been said "you must endeavor to persevere".

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    • #3
      That old "MURPHY" has been around a LONG time, the old coot has been hangin around my little shop at times too!

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      • #4
        And people wonder why I hardly ever make dimensioned drawings of stuff I want to build.
        Any products mentioned in my posts have been endorsed by their manufacturer.

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        • #5
          Originally posted by winchman
          And people wonder why I hardly ever make dimensioned drawings of stuff I want to build.
          Nah, the drawings are dimensioned AFTER you have machined the parts Or the dimensioned drawings are "updated" after manufacturing
          Amount of experience is in direct proportion to the value of broken equipment.

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          • #6
            Remember when you think you have all your Ducks in a row-Murphy thinks it's a shooting gallery
            I just need one more tool,just one!

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            • #7
              As long as part A fits part B it's OK, this is hobby work not production work.
              The shortest distance between two points is a circle of infinite diameter.

              Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

              Southwestern Ontario. Canada

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              • #8
                Originally posted by Jaakko Fagerlund
                Nah, the drawings are dimensioned AFTER you have machined the parts Or the dimensioned drawings are "updated" after manufacturing
                Exactly - fire your shot - THEN draw the bullseye!
                Tel

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                • #9
                  I'd like to help you out but Murphy's second law is "No good deed goes unpunished" , I've learned a lot from my mistakes, but evidently I still have a lot to learn.




                  .

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                  • #10
                    Yeah, I suppose if I was really interested in making them more accurately, I would get a second one and repeat the process with all I learned from the first. What's the fun in that? The joy for me is the head scratching, and figuring out just how in the heck am I going to get each piece into shape. I just had the fecal touch yesterday. Other nice thing is this particular vendor will replace a part pretty inexpensively, if you wanker it up beyond recovery. Don't ask how I know this.
                    I'm here hoping to advancify my smartitude.

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                    • #11
                      Originally posted by Tel
                      Exactly - fire your shot - THEN draw the bullseye!
                      I like that philosophy . Back long ago in chemistry class, we called that doing a " dry lab". You start with the known correct conclusion, and write your report backwards . No actual wet chemistry involved.
                      ( But you know, 46 years later, I still feel guilty about that. Having a conscience is tough.)

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                      • #12
                        Murphy has been around here a lot longer than any of us, just think of the experience HE has.
                        mark costello-Low speed steel

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                        • #13
                          I think sprues are why God invented the belt sander

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