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Thread: Cylindrical Square Project

  1. #11
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    Aug 2009
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    Before I get started do you have a source part number etc. for the Cat wrist pins????? I'm sure they come in a variety of sizes.

    If I had a pin for these pistons and rod I would be all set.

    JL...............




  2. #12
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    Mar 2002
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    I am with Rich on this. Mine came out of a large truck engine. Not sure of the make or model but it shows absolutely no sign of wear so could be brand new. It is as accurate as any of my gear can test.

  3. #13
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    Quote Originally Posted by MichaelP View Post
    If I understood the ring description correctly (analog of the bottom ring on ceramic cups on which the cup rests), I think it would be easier to turn the rings and then the center holes while holding the cylinder in a lathe chuck. Then proceed with the final turning/grinding between centers including facing of the rings.

    I don't have a cylindrical grinder, so I'd either do it with a TPG (Toolpost Grinder) or on a surface grinder between centers. If done with a TPG, I'd, probably, prefer facing the rings with a lathe tool bit (vs. grinding wheel) to make whole bottom surface of the ring perpendicular to the cylinder axis. Because if I use an OD grinding wheel on TPG, it will be hard to achieve (although it wouldn't matter much anyway: this will only affect the total contact area with the surface plate).

    Please feel free to criticize any possible flaws in my mental exercise.
    Yes you are correct, the part of course has to be made in a chuck before being finish turned between centers. I tend to skip some details once in a while, but should really pay attention in writing things out more carefully.

    If your TPG wheel is trued from the side also, touch the end of the square (the ring part) with it to true the end. And unless your wheel is as thin as a cutoff disc there is no issue in doing so. On a cylindrical grinder that's the most efficient way to remove metal, as it acts like a horizontal Blanchard grinder.
    Amount of experience is in direct proportion to the value of broken equipment.

  4. #14
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    Wrist pins are not as cheap as I thought they would be. I don't know what size the one in the picture is but I'm guessing it fairly large.

    JL..................

    https://puredieselpower.com/ford/03-...rist-pins.html

  5. #15
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    I have a 14" length of 3" diameter chrome plated column from an Instron tensile testing machine that was being shortened due to the ceiling in its new home being lower than its old home. Its diameter is constant to better than a tenth all the way along. Haven't got around to turning the end yet, but it's on the list of things to do.

  6. #16
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    High, Wide and Handsome, Montana
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    There are fairly cheap CAT wrist pins on Ebay. Im sure searching for other makes would show more.

  7. #17
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    Quote Originally Posted by Mark Rand View Post
    I have a 14" length of 3" diameter chrome plated column from an Instron tensile testing machine that was being shortened due to the ceiling in its new home being lower than its old home. Its diameter is constant to better than a tenth all the way along. Haven't got around to turning the end yet, but it's on the list of things to do.
    Oddly enough I had the same problem in the test house in port talbot, in my case it was only a case of removing some suspended ceiling!
    Mark

  8. #18
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    The wrist pins may be perfectly round and have exact dia's. to the tenth on each end but are the ends square ? I'm guessing not square enough to become a precision cylindrical square without some work. The ends of a wrist pin are really an insignificant surface since all they contact is the spring or circlip.

    So I you happen to find one now your tasked with squaring up at least on end.

    JL...............

  9. #19
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    Quote Originally Posted by softtail View Post
    There are fairly cheap CAT wrist pins on Ebay. Im sure searching for other makes would show more.
    can you show me where? i found just two.

  10. #20
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    Quote Originally Posted by dian View Post
    can you show me where? i found just two.
    I haven't been able to find any either. My searches all come back with mostly wrist pin bearings and not the pins themselves. The wrist pins I have been able to find don't give the dimensions of the pin, just the make and part number. If you repairing a motor you don't need the dimensions, just the correct PN#. So yea, if you could find something it would be appreciated. I guess these people weren't thinking of us guys that might want to use them for cylindrical squares.

    JL...................

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