Announcement

Collapse
No announcement yet.

need an idea

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • need an idea

    I have this part. It slides up and down a ground rod. It's called an "end weight" on a Globe meat slicer. The bad news is that the bronze bushings are worn so there appears to be about .003" of slop, which is enough to cause the part to bind up. The worse news is that the bushings are pressed into circular pockets such that zero or almost zero of the bushing's ID is available on the inside to push the old bushing out. So I'm looking for a clever idea as to how to remove the bushings, one at each end. The bore is only about 2-1/2" long so I could easily get a punch to bear from the back end except there's nothing to catch if you get my meaning.

    I am familiar with the old dodge of somehow injecting grease, getting the grease to push out the bushing(s). But if there's nothing for a punch pin to push against, there's nothing for grease to push against either.

    The bore is about 0.437" on the bushings. I'm thinking of trying to tap them 1/2-13 and pull them out with a bolt. Don't see any way other than to keep on tapping right past the bushing (only about 3/16" tall) into the part's bore, though. And there wouldn't be much "meat" for the bolt to grab onto.

    I suppose I could braze a plug in there. Then it would be possible to punch it out from the back.

    Ideas? Comments?

    metalmagpie

  • #2
    Bore it out?
    turn it into chips instead of pulling it as one piece.

    though I like tapping. Why are you tapping into the part? Bushing too
    short? flat-bottom tap?

    I've seen pipe extractors with the cam tip to grip from the inside, problem
    is it'll put pressure in the wrong way but maybe if you get it spinning it'll
    work its way out?

    Comment


    • #3
      Tap and Hammer

      If I understand what you have then tap one bushing and run in a bolt. You now have something to punch against. Tap the second bushing and repeat with the hammer.

      Comment


      • #4
        I think I might try tapping the hole and using a bolt as a puller. I'd probably drill the hole out to 29/64 and use the fine thread, 1/2-20, to get more thread engagement. It's still not great, only 3 3/4 threads, but it's lot better than the approx. 2.4 threads you'd get with 1/2-13.

        There is also a NEF thread, 1/2-28 (tap drill 15/32), that would give you 5 1/4 threads of engagement in the 3//16" thick bushing, which is looking really good.

        At this point I expect you are looking at the need to buy a tap -- I would be. Is the project worth the price of a tap? Up to you....
        ----------
        Try to make a living, not a killing. -- Utah Phillips
        Don't believe everything you know. -- Bumper sticker
        Everybody is ignorant, only on different subjects. -- Will Rogers
        There are lots of people who mistake their imagination for their memory. - Josh Billings
        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
        Don't own anything you have to feed or paint. - Hood River Blackie

        Comment


        • #5
          Turn a steel shaft for a close fit into the existing bushing, then concave the end of the shaft as much as possible, leaving the edge sharp. Then bandsaw into the end from two rotations, leaving four fingers. Jam something in the cuts to spread the fingers a bit in both directions. Turn it again to get most of the OD on the fingers down to the shaft size.

          Insert the shaft from the uncut end and force the finger end into the bushing about halfway or so. Now as you apply force on the shaft, the sharp edges on the fingers will dig in and get a hook on the bushing.
          I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

          Comment


          • #6
            I think I would just bore it out.

            The objective is not to entirely cut out the bushing, but make it really thin (few thousandths).

            I've even purposely been off center a few thou and just sneaked up on it. You'll break through 1 side of the bushing and it's much much easier to pull out. If the bushing is brass/bronze, just center it bore it. Steel is stiffer can offsetting it tends to make it a bit easier to remove the bushing.

            If you're careful, you don't touch or damage the hole that the bushing sits in.

            Comment


            • #7
              The problem with boring it out is holding the dang thing. See the part:

              http://www.oldhobartslicerparts.com/...l/100_4860.JPG

              I'm not saying it isn't possible. Just doesn't seem practical.

              The quartered concaved shaft driven halfway in is pure genius. Sadly, I have sold my last metal lathe and my neighbor who loved to help me out died, and my other buddy who is willing to help me out usually is extremely busy. So I'm kind of on my own.

              metalmagpie

              Comment


              • #8
                Start a tap in to it and then drive it out from the other end by hitting the tap.

                Comment


                • #9
                  Bore it out on a mill.

                  Comment


                  • #10
                    I thought of another trick. Drill a cross-hole right through the part and the bushing. The bushing's OD is 3/4". Take a spring pin that fits the drilled hole and either buy it 5/8" long or cut it off at 5/8". Drive it completely in, so it fits completely inside the bushing. Then put a long pin through the bore so it bears on the spring pin, and tap it out from the back side.

                    I'm not going to do it, because of the nature of this part - it's a meat slicer, with intimate contact with biological material and I don't want to create another crevice for germs. But I like the idea ..

                    metalmagpie

                    Comment


                    • #11
                      Drill it out with successively bigger drills untill one gets stuck and rips it out because it catchs badly. :P
                      Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                      Comment


                      • #12
                        Use a die grinder or dremel to grind through one side of the bushing. Then a sharp punch to bend it in and close that gap. Should now be easy to push out from the other side.

                        After doing that, I might strongly consider reaming the whole thing and pressing in a full length bushing.

                        Comment


                        • #13
                          mini hacksaw. Thread the blade through and reattach. Then cut through, or part way through the sidewall.

                          Surely you have one of those mini hacksaws. You know those cute little things that beg you to buy one from the end of the aisle bins. You can immediately think of a million reasons why you need one, but when you get it home it sits for years in your toolbox unused because anytime you need a hacksaw you need a real one. Then after a couple years of lying dormant in your toolbox you forget it's there because you've never used it. Then one day you're cruising the local hardware store and you come to the end of the aisle.......I think I have 3.

                          Comment


                          • #14
                            Originally posted by Dan Dubeau
                            mini hacksaw. Thread the blade through and reattach. Then cut through, or part way through the sidewall.

                            Surely you have one of those mini hacksaws. You know those cute little things that beg you to buy one from the end of the aisle bins. You can immediately think of a million reasons why you need one, but when you get it home it sits for years in your toolbox unused because anytime you need a hacksaw you need a real one. Then after a couple years of lying dormant in your toolbox you forget it's there because you've never used it. Then one day you're cruising the local hardware store and you come to the end of the aisle.......I think I have 3.
                            Hah, I remember a post about a guy saying he got paid very well to snap his bandsaw blade and reweld (Or maybe he just melted the braze and rebrazed it, in retrospect..) it after puting it through a hole in a workpeice to saw some large feature in or another..
                            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                            Comment


                            • #15
                              Pretty common problem - many blind hole bushings out there. At least you can get to both sides!

                              Insert slide hammer blind bearing puller, pull out.

                              Or.. grind a couple of pockets, insert Stihl oil seal puller, lock and pull out.

                              Drilling or tapping? many times the bushing will spin, so just use the tap to grip and then push out.
                              Last edited by lakeside53; 08-04-2011, 02:17 AM.

                              Comment

                              Working...
                              X