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  • Broken Casting-I need help.

    After an episode of engine hoist rentals, jury-rigging, and co-ordination, I finally sucseeded in getting the borrowed Rotex vertical mill into my dad's garage. And I have a problem.

    While the mill fits generally into the category of "worn but in good condition", there is one problem. On the head, the two "ears" on the quill housing that form the quill lock when pulled together have been overstressed. One of them (the one without a tapped hole) has cracked most of the way through.

    What do I do?

    I can lock the quill OK, without any appearance of widening the crack, but it really does not look good. Is there a way to repair this?

  • #2
    Without going thru a whole lot of trouble......
    The short answer is No.

    If it ain't broke don't fix it.

    Comment


    • #3
      Well, then, what do I do when the last 5 milimeters of cast iron cracks all the way off?

      Comment


      • #4
        Can you post some pictures so we can look at it? Picture are worth a whole bunch of ?????????
        Mel
        _____________________________________________

        I would rather have tools that I never use, than not have a tool I need.

        Comment


        • #5
          I would say cross that bridge when you get to it.

          Then bring it up on the welding board.
          To weld the thing you will need to tear it down, and hope you find a good enough welder to lay a bead that will hold and not require machining afterwards.

          Until then, try to use the quill stop setting to lock the quill up as far as it will go when you are milling. if you are drilling you can still move it down.

          Comment


          • #6
            Braze it with Ni-Cu brazing rod.

            I did repairs to several parts on a Sheldon lathe a few years ago and did the repairs with Harris-Welco 17-4FC nickel silver brazing rod. The process didn't distort the castings, is very machinable and is actually stronger than the base iron casting.

            If things are working now, it probably isn't the time to fix it. When it does finally go, consider the H-W 17-4FC as it worked really well for me, given the proper braze joint preparation, clening and fluxing.

            Comment


            • #7
              http://www.locknstitch.com/
              This product may help. Allen

              Comment


              • #8
                Post a photo. I have a horizontal mill with a broken ear on the overarm support lock and have been debating what to do about it. The piece is there, but it needs to be reattached somehow. I'd like to see what your cracked ear looks like and if any suggestions will work for me (obviously the "wait until it breaks" suggestion has already come to pass ).

                andy b.
                The danger is not that computers will come to think like men - but that men will come to think like computers. - some guy on another forum not dedicated to machining

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                • #9
                  Take a piece of flat iron . Lay the one you have that is cracked on top and scribe around it and carve one out of steel . It wont crack ever again. You have onr to make a copy of . machine it out that simple. Hot roll steel will be plenty good enough.
                  Sorry I `m thinking of the wrong part. Want work . We could simply this process if people would show a picture of problems.
                  Last edited by lane; 11-15-2009, 09:37 PM.
                  Every Mans Work Is A Portrait of Him Self
                  http://sites.google.com/site/machinistsite/TWO-BUDDIES
                  http://s178.photobucket.com/user/lan...?sort=3&page=1

                  Comment


                  • #10
                    Originally posted by Jpfalt
                    I did repairs to several parts on a Sheldon lathe a few years ago and did the repairs with Harris-Welco 17-4FC nickel silver brazing rod. The process didn't distort the castings, is very machinable and is actually stronger than the base iron casting.

                    If things are working now, it probably isn't the time to fix it. When it does finally go, consider the H-W 17-4FC as it worked really well for me, given the proper braze joint preparation, clening and fluxing.
                    I've been accumulating a pile of broken cast iron parts that need brazing or welding and I thought I'd give your recommended rod a try.

                    However, I Googled and found Harrix 17 FC but didn't find any references to 17-4 FC. Could you confirm that it's really 17-4?

                    Thanks,

                    Bob

                    Comment


                    • #11
                      He is talking about the cotters that lock the quill. Make some new ones in the lathe out of brass or bronze.

                      http://www.frets.com/HomeShopTech/Pr...quilllock.html



                      --Doozer
                      Last edited by Doozer; 11-15-2009, 09:57 PM.
                      DZER

                      Comment


                      • #12
                        You're right, It's 17FC

                        Bob,

                        I checked the package and it is 17FC.

                        It comes flux coated, but I add additional silver solder flux or borax when I do the braze.

                        The joint is opened up to a vee that goes through the part. Grinding tends to wipe graphite over the surface. The graphite interferes with the braze flowing and wetting the surface, so I file the surface a few strokes to leave a clean metal surface.

                        Then I flux and start heating with an oxyacetylene torch to tin the filed surfaces. Once the surfaces are tinned, I jig them in place and fill the vee. Just like silver solder, you need to heat the base part until the braze material melts and flows onto the surface. Also like silver solder, the braze flows to the hottest spots.

                        That's about it other than filing or remachining to dimension and appearance.

                        Comment


                        • #13
                          Thanks,

                          I'll give the 17 FC a try.

                          Comment


                          • #14
                            The mill does not have cotters. The way it works is that the bottom inch and change of the head is slit, and at the back are two ears that flex the cast iron tightening it onto the quill. And one ear is cracked. Pix coming later.

                            The stitching pins do sound interesting. But I wonder what sort of strength they have.
                            Last edited by Teenage_Machinist; 11-16-2009, 01:15 AM.

                            Comment


                            • #15
                              The first thing to do may be to drill a stop hole at the end of the crack to prevent it from spreading. Check inside and out to make sure you really get the end of the crack - if you don't it won't do any good. Clamp the part while drilling so that drilling doesn't spread the crack. This will buy you some time. If you are lucky, a lot of time.

                              The hole spreads the force. A crack concentrates the force in a small area which allows a relatively small amount of force to split the metal.

                              You might do a dye penetration test to make sure you can all of the crack, even parts not visible to the naked eye. IIRC, you coat the surface with some dye so it soaks into cracks, wipe the dye off the surface and then apply a paste of talcum powder (talc, baby powder) and water which will be stained when the dye seeps back out of the crack. Let it sit. Clean it off when you are done as it is a mild abrasive.

                              Then you might machine a steel clamping collar that fits over the existing collar. You may be able to machine it so even if the original piece breaks off entirely it will still be captive.

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