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Repairing milling attachment for Craftsman/atlas lathe

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  • Repairing milling attachment for Craftsman/atlas lathe

    Last night I made a craigslist purchase of an old craftsman 12" lathe just so I could get some of the accessories. One of them was the factory milling attachment. After I got home and was making a close inspection of my haul, I noticed a slight bulge below each of the retaining pins indicating that sometime in the past the mill was forced against the pins and cracked the cast iron around the holes out....

    Just curious how I should go about fixing this? Any ideas? My first thought is to just knock out the broken parts, weld, machine, and re-drill the holes, but my cast iron experience is limited to knowing that it can be tricky stuff....

  • #2
    If you can post a pic of it we may be able to get a better idea of the problem.

    Mtw fdu.

    Comment


    • #3
      Having no picture to help me fully understand the problem, I'll offer the following experience.

      I obtained an Atlas MF Mill with vise. Upon cleaning up the vise i discovered that at some point the fixed jaw had bee broken off and repaired with brazing. So far this repair has worked well and not shown any signs of breaking again. With common sense use it will probably be fine for as long as I want the Mill.

      So, that all said, perhaps brazing would be an acceptable repair for your issue.

      Comment


      • #4
        Thanks for the responses. I'd considered brazing but since this is probably the point where all the leverage against the whole mill concentrates I was concerned it might not be strong enough.

        I need to clean the attachment up so the damage will show up in a photo. I'll probably start on that tonight and see about posting pics tomorrow.

        Comment


        • #5
          The pin and taper system isn’t up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
          One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
          Don’t apply heat!
          Good luck, Mike

          Comment


          • #6
            Mike,sounds like a great mod. Any chance of getting a picture of this mod. I think a lot of us will be doing this. Thanks! Eric

            Originally posted by mf205i
            The pin and taper system isn’t up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
            One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
            Don’t apply heat!
            Good luck, Mike
            "Let me recommend the best medicine in the
            world: a long journey, at a mild season, through a pleasant
            country, in easy stages."
            ~ James Madison

            Comment


            • #7
              I'm not sure what "pin" you're talking about. The picture below shows the Atlas Milling Attachment. The only pins I know of are the beveled pins that fit against the swivel when you pull the compound off to mount the attachment.

              Comment


              • #8
                Originally posted by mf205i
                The pin and taper system isn’t up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
                One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
                Don’t apply heat!
                Good luck, Mike
                .
                .
                i too would like to see a pix. . .

                Comment


                • #9
                  Originally posted by hal9000
                  I'd considered brazing but I was concerned it might not be strong enough.

                  Don't underestimate the strength of a properly done braze joint, it most likely will be nearly as strong, or even AS strong, as the original cast iron. If you do decide to weld this thing brazing would probably be a much better way to do it than arc welding with Nickle rod.

                  Comment


                  • #10
                    The stud he is referring to is the dovetailed boss sticking up from the cross-slide, to which the milling attachment or compound clamps. You drill and tap this for that bolt which goes vertically through a new hole in the milling attachment down into the threaded hole.
                    Great idea BTW.

                    Comment


                    • #11
                      Sorry for the delay in pictures guys.... busy weekend. I'll get them tonight hopefully.

                      CCWKen, I am indeed referring to the bevel pins that fit against the swivel. I was having a "duh" moment and couldn't come up with the correct description for them when I first posted.

                      I too would love to see photos of the completed mod that Mike described. Sounds like the path of least resistance in terms of repair. My only question would be how critical the centering of the drilled and tapped hole in the cross slide stud is? I'm assuming that it's a standard drill press operation right? Otherwise i could envision something like mounting the stud in the lathe jaws and drilling from the underside using the tailstock to get things perfectly centered....

                      Second choice at this point is to re-drill and tap new holes for the bevel pins in a different location (probably 3 pins, one dead center between the originals, and one each on the machined boss for the zero marks on the base of the attachment)

                      Comment


                      • #12
                        Here are a few shots. If you look carefully you can see the cracks. You can also see the bulge on the opposing pin (the one not in view) if you look very carefully.



                        Last edited by hal9000; 06-11-2012, 07:18 PM.

                        Comment


                        • #13
                          I'd just braze it, clean up the braze and threads, make sure it's still flat (and if not flatten it using best method you have, or take it to some one that can make it flat again) then use it.

                          But then I'm used to brazing cast, if you are not comfortable brazing it then I'd say go get someone that is good at it to do it. The part is well worth the repair, I use mine very often.

                          Comment


                          • #14
                            Do you mean flow braze into the cracks? Or break the casting completely or V the cracks out and braze?

                            Somebody also suggested silver solder as a better flowing alternative. I might experiment on some scrap since I have some 15% silvolux lying around.

                            Comment


                            • #15
                              Originally posted by hal9000
                              Do you mean flow braze into the cracks? Or break the casting completely or V the cracks out and braze?

                              Somebody also suggested silver solder as a better flowing alternative. I might experiment on some scrap since I have some 15% silvolux lying around.
                              Sorry for the delay in getting back to you I was out of town yesterday. I did mean braze, but I'd also have stablized the cracks first. But if you have the silver solder and it's high silver content (there are lots of silver --scratch that I just saw you said 15%.

                              So in light of that silver solder would no doubt be a better choice, but clean, clean, clean (and unless you are already comfortable soldering) practice on something else first --as I see you said you would.

                              Here's a fairly good primer about it, if it will help:
                              http://www.astronomiainumbria.org/ad...h/t-solder.htm

                              Brazing would be a better with more open fault areas, but it also can flow into cracks, but the silver solder is quite a lot easier and probably better suited to the task you have.

                              Be sure to report the outcome --even if something goes not quite the way you want (I think it will go just fine, but if it doesn't don't give up hope --learning is like that and there are lots of helpful people here).

                              Comment

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