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Trying to remove a stuck post in casting

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  • #16
    KROIL! And maybe some heat, then more Kroil. Bob.

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    • #17
      Update - washer between the nuts didn't work - buddy thinks he has some Kroil and is digging for it, otherwise I'll order some.

      Might get to try the heat/cool later tonight.

      Here's a pic of the offending piece - This is on the corner of the saddle casting for the lathe carriage. The casting had been dropped (I have inspected it carefully with a loupe and a buddy is doing a dye test on it Monday). This post is bent slightly but it's hard to see at this angle. The base of this post and the post looks to be all one turned piece and I am told by others with the same lathe that theirs was screwed into a tapped hole in the casting, not screwed in.

      Will update more as I move along (hopefully moving forward)

      Lewis

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      • #18
        some studs are left hand on the bottom half

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        • #19
          Now that I see the pic, I can see that you cannot determine if it is threaded. Good thought on the left hand tread though. Can you see the other end of the stud? Might be some evidence of a thread, right or left. Let us know what works. Bob.

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          • #20
            Even if others have lathes with the stud screwed in, do not be surprised if yours is pressed (or has left hand threads). Manufacturers in those days tended to not have their processes standardized as well as they do today and repairs sometimes change things.

            I would definitely first try straightening the stud, clamping the casting for safety against breakage. If I had to remove it without damaging the casting I would carefully cut it off and progressively drill it out. When the remains get thin enough you can pick out the remains, whether threaded or pressed.
            Don Young

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            • #21
              Yes, watch out for left hand threads! Yesterday I had to remove the knuckle ends from 12 awg shear actuator arms. The owner had soaked them in gallons of penetrating oil, heated, cooled and beat the crap out of them... no go.

              A little investigation and I could see the threads; sure enough... a quick whack "the wrong way" and they unscrewed. lol...

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              • #22
                I'm back on the sofa with the laptop for the evening now, so I will try that left hand thread idea tomorrow morning - that never crossed my mind.

                As for the production processes not being standardized - I have come across that in one or two places so far - little taper pins being used where someone else had a straight pin for example.

                Another thought just crossed my mind too - there's an engineering place in town that has an xray inspection setup - I might just show up there with the casting in hand and play the "almost retired guy trying to rebuild a metal lathe for a hobby" card and see if they take pity on me and give it a zap. That would tell me if it's threaded or not ! Then again they might want to charge me a small fortune....doesn't hurt to ask though.

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                • #23
                  Originally posted by duckman
                  Why is it nobody remembers to put a washer between the nuts when your trying to remove a stud, 2 nuts won't lock.
                  ... I broke a 3/8" stud with two nuts and a cheater pipe. No washer ... just two nuts threaded on by hand and then tightened against each other with wrenches...

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                  • #24
                    I confess I didn't know the washer trick. In trying to think how/why, with no space, there is no distance for the threaded section to stretch which is what gives you the holding power.....ie the inclined plane of the thread strains the fastener along its axis creating the force holding it together. maybe that's why they break without a space - ie all the force shows over a very short section so is more torque twisting it than strain elongating it?

                    best I could come up with
                    .

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                    • #25
                      Originally posted by Mcgyver
                      I confess I didn't know the washer trick. In trying to think how/why, with no space, there is no distance for the threaded section to stretch which is what gives you the holding power.....ie the inclined plane of the thread strains the fastener along its axis creating the force holding it together. maybe that's why they break without a space - ie all the force shows over a very short section so is more torque twisting it than strain elongating it?

                      best I could come up with
                      It broke at the casting, not where the double nuts were. Of course, the nuts I'm accustomed to have a slightly raised bearing surface - the threads terminate before the face of the nut.

                      Even with the threads right up against each other, it shouldn't matter. You are still straining the fastener along the axis, except that the strain is localized to the root of the thread between the two nuts. I can believe that adding a washer makes it easier to implement, but I can't see why (either theoretically or based on experience) that it is neccessary.

                      Edit: LHC, if you do happen to break the stud at the casting, instead of drilling it out, consider using a torch. Cast iron won't burn like the steel so you can often carefully blow the steel out and leave the threads intact. I've done that several times after someone here told me about it.
                      Last edited by Fasttrack; 04-29-2012, 01:50 PM.

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