Rupnow-Johnno Vertical hit and miss

Discussion in 'A Work In Progress' started by Johno1958, Sep 8, 2019.

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  1. Nov 10, 2019 #41

    awake

    awake

    awake

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    As someone who has yet to try this - your results look good, and I predict the next one will be perfect!
     
  2. Nov 10, 2019 #42

    el gringo

    el gringo

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    My thoughts exactly!!
    RAY M
     
  3. Nov 10, 2019 #43

    110samec

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    As an aside, the rudder stocks on Archer class boats (Royal Navy) have brass keys, mainly so that any slop in the system that develops wears out the cheap to replace key rather than the expensive steel steering arm. Had to machine a new key last week for one
     
  4. Nov 10, 2019 #44

    Johno1958

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    Thanks guys I'll get there eventually .If I need to make a dud or two to get a good one ...well and good It's the only way I will learn.
    I will try some different metals .The key steel was ok to machine but felt very dry and for me did not finish very well.I used a parting tool to cut
    the crank throw so I will look into a better tool for that if there is one. I have some 4140 I can try...maybe a little hard .
    John
     
  5. Nov 10, 2019 #45

    Brian Rupnow

    Brian Rupnow

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    John-I just machined some 4140 for a fixture a customer wanted. It is really, really tough stuff. I'm not sure you could machine it with HSS cutting tools. I used carbide endmills to shape the part. Very nasty stuff. I have used 12L14 for my last two crankshafts. As far as warpage of the crankshaft from internal stresses go, it is much better to use hot rolled steel bar (Commonly called A36 here) than cold rolled steel.
     
  6. Nov 11, 2019 #46

    el gringo

    el gringo

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    Yes Brian,
    I also had very good luck using 1144 stress proof as suggested in your vertical hit and miss engine build.
    Ray M
     
  7. Nov 17, 2019 #47

    Johno1958

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    As luck would have it a mate of mine had some 1' round cold rolled 1144 he bought from Amazon a couple of years ago and gave me what he had left a 7" length. IMG_20191116_115242.jpg
    Milled it down flat and had another go.Cuts like butter. Problem with using the round is when I make the counter balance and fit them there will be a little day light showing in the corners . IMG_20191117_141854.jpg
    All done.
    John
     
  8. Dec 2, 2019 #48

    Johno1958

    Johno1958

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    I bought some 1214 steel to have another go at crankshaft making and this one I like. I will have to sand a little as the bearings are a bit of a tight press fit
    at the moment. Hopefully It is the last crank I have to try make for this engine but I need the practice........
    John
     
  9. Dec 3, 2019 #49

    awake

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    To avoid the "daylight" in the corners, mill those edges flat - shouldn't take but a minute or two. Unless your shop skills are like mine, in which case it will take an hour or two, with much of the time spent trying to remember where I put the tool I just set down half a second ago ... :)
     
  10. Dec 3, 2019 #50

    Johno1958

    Johno1958

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    Yep I'm hearing you there lol
     

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