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Thread: Dumb machining questions. The jig that an engine gets bolted to for machining called?

  1. #1
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    Default Dumb machining questions. The jig that an engine gets bolted to for machining called?

    The round bar that a guy would bolt an engine too using the mains which then sits between two centers, whats that called? Is it a make it yourself kind of deal? I have a small engine I need to bore the cylinders on and need to get at it soon.

    Like in the pic but without the power unit.

    Andy

  2. #2
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    Well, in general, contraptions or devices whose purpose is to hold work pieces in the proper place and alignment for machining are called fixtures, as I understand the term.

    In the world of engine building/machining there may be some more specialized term, but if so I know it not. If I were going to coin such a term, I'd probably call it a "dummy crank."
    Last edited by lynnl; 05-31-2019 at 08:13 AM.

  3. #3
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    yup, you want to call it fixture to find it searching. jigs are for drilling.

    RMC, who's photo you show calls it "4th Axis Rotary Table and Block True Blueprinting Fixture"

    I don't know that you are going to get anything more exact than "engine block fixture". page 2 here

    https://rmcengine.com/wp-content/upl...18-Webpage.pdf

    PS....I'd guess the engine is bolted to the t slotted face place rather than sitting between centres. I wouldn't think it would be rigid enough just attached to a bar between centres, no first hand knowledge, but that would seem too light a set up
    Last edited by Mcgyver; 05-31-2019 at 08:27 AM.
    .

  4. #4
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    Andy

  5. #5
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    Quote Originally Posted by vpt View Post
    I found this old gem. Post # 796
    there you go....looks like it would work after all.
    .

  6. #6
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    DZER

  7. #7
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    I would call it a mandrel.

  8. #8
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    I'd call it a crank locating, cylinder boring fixture.

    A simplistic definition, fixtures hold the work, jigs are held TO the work. It can get more complicated and blurry than that, but that's pretty much the jist of it.

  9. #9
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    Jigs guide cutting tools.
    Fixtures hold the workpiece.

  10. #10
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    Check out Goodison Supply, they carry a full line of engine machining/rebuilding supplies/tools...I believe BJH make a block truing jig for a Bridgeport style mill to do most of the block machining,( lifter bores, deck, boring) not cheap .. http://bhjproducts.com/bhj_content/p.../bt1_intro.php Good luck!

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