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Need to remove 5MT arbor from Jacobs 20N SuperChuck

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  • #16
    if 30 tons doesn't move it, wedges won't.
    I had a smaller one - wedges absolutely did nothing. Finally pressed it out in a smaller (12T) press - and yes, let go dramatically.
    "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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    • #17
      I have to look but I think I bought an Albrecht chuck on a MT4 taper. I will have to look what size it is. Maybe if you talk nice to me I will send it to you.
      Location: The Black Forest in Germany

      How to become a millionaire: Start out with 10 million and take up machining as a hobby!

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      • #18
        Forget the wedges you need heat. I wonder if there isn't some lock tight in the taper also and heat will help that too. If its that stuck I hope you find the chuck taper is ok when the arbor comes out.
        Mike
        Central Ohio, USA

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        • #19
          I just did two 14Ns, one by drilling a 5/16 hole through the chuck and pressing it out with a 10T press. Made a big bang when it let go, loud enough to make my ears ring for a while (wore ear protection for the second one). The second one was a mess and the 1st one I tried. Ended up cutting the arbor off, drilling out the majority of the bit in the chuck, cutting the side of it with a carbide burr and THEN pressed it out. What a PITA. My mistake was not making the hole big enough, so all the pins I tried bent/ broke.

          I have an 18N to do soon and I'll be using a 3/8" pin at least

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          • #20
            I would go with the cut off and drill the main body of the short taper to lower the grip as already suggested. Leave a 1/4" undrilled at the chuck end. The dimensions of the short Jacobs tapers can be checked first to drill without damaging the chuck body.

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            • #21
              When you beat on the end of the arbor, you expand it. The trick is to drill into the arbor to slightly past the depth of the chuck body. The driving punch needs to sit solidly on the bottom of the pocket you just made. Now when you press it out, the arbor will stretch and become smaller. Always works.
              Mike

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              • #22
                Originally posted by mattthemuppet View Post

                I have an 18N to do soon and I'll be using a 3/8" pin at least
                Was gonna say, I used a hardened 3/8 pin on mine, anything else would just bend or break. A cheapo from HF. I sat it across the vise jaws and got on it with the 10-lb sledge. Bang. Popped right out after a few shots.
                25 miles north of Buffalo NY, USA

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                • #23
                  Thank you all for your responses. I plan to drill the hole in the chuck a bit larger in diameter and drill a bit into the arbor. Then I'll get out the torch with a small tip to try to get some quick heat in the chuck body and be able to beat it prior to most of the heat transferring into the arbor.

                  My 30T hyd press is on of the bottle jack set ups - though I modified the press so that the down rod travels in a loose fit plastic bushing to keep the rod in alignment so I don't **think** that the press is loosing too much force to side loading (but without a gage I can't be certain what the bottle jack is puting out). I did not hang from the pump handle to get maximum force - guessing maybe the press was somewhere near 15 to 20 T on the arbor. I've popped off some good sized 4MT arbors in the past, both by striking the arbor with a shaft and by using the press and I am quite aware of the percussive sound of the arbor as it slams into something.

                  Hey BF - if you were at least on the same continent (and your Albrech was a decent size) I might be interested in doing a trade. BTW, what's with your new avatar? Previous avatar looked like your were going native - expected to see you in full Lederhosen costume in the updated avatar!
                  Metro Detroit

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                  • #24
                    Originally posted by mf205i View Post
                    When you beat on the end of the arbor, you expand it. The trick is to drill into the arbor to slightly past the depth of the chuck body. The driving punch needs to sit solidly on the bottom of the pocket you just made. Now when you press it out, the arbor will stretch and become smaller. Always works.
                    Mike
                    That's a very interesting concept.


                    JL......

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                    • #25
                      Here is something that has worked for me with stuck tapers.

                      Yes, put it back in the press and apply some pressure but not the max.

                      Heat the chuck with a heat gun until everything is warm. But not hot enough to change the temper of the metal.

                      NOW, quickly hit the exposed adapter with a generous blast of FREEZE SPRAY. Try not to hit the chuck with it. I have had them just drop out at that point. If it doesn't, quickly increase the pressure or use some hammer blows on the adapter.

                      Some Kroil would not hurt.

                      No freeze spray in the shop? Here's a tip. Freeze spray and canned, compressed air have only one real difference: the freeze spray has an internal tube to pick up the liquefied gas at the bottom while the canned air does not so the gas at the top is what you get. If you turn a can of canned air upside down it becomes freeze spray and if you turn a can of freeze spray upside down you get compressed air. This is another trick I have used many times.
                      Paul A.
                      SE Texas

                      And if you look REAL close at an analog signal,
                      You will find that it has discrete steps.

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                      • #26
                        Some of this may seem obvious, so forgive me for writing it. Drill out the center hole to ½". Make a press plate from heavy steel with a hole that the arbor just fits through. Use that to support the check when pressing it. Use a grade 8 bolt to push the arbor out. It should just stick out of the chuck jaws a little when they are loosely closed against the bolt. Support the press plate squarely in the press. Now apply some heat around the base of the chuck, not on the sleeve and put the pressure to it. As was stated several times, have a bucket with something soft to catch the arbor. This method is approved and recommended by Jacobs.
                        Grantham, New Hampshire

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                        • #27
                          I have done this a few times cut the arbor off put the chuck in the lathe dill and tap what's left of the arbor cut a pace of pipe and make a thick washer use a stud or bolt and use your impact gun and they pop right out if you want to keep arbor weld a bolt to the end do the same with the pipe and washer I have found that the impact gun works better than the press ken

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                          • #28
                            Here's what works for me on on difficult projects. One particularly noteworthy project was a large rotary ditch digger had developed bad bearings on the main impeller shaft. It was 36" long and 3" in diameter completely enclosed in a tube with large bearings at top and bottom. Two days of effort with large sledge hammers, aerosol penetrating fluids by the case, and acetylene heat, yielded no results...no movement. I had heard about using a 50/50 mix of ATF and acetone, so as a last resort at the end of second day, we put a bunch of that mixture where it was stuck. Next morning we checked and the shaft was settled to the floor and slid out easily. We were just dumbfounded and made us believers. I keep that mixture (it's not a solution so you have to mix it like a rattlecan) in a spray bottle that will withstand the acetone and use it on difficult tightly stuck and rusted stuff. Most often, it works without any heat which is a good thing because it's extremely flammable.

                            DanK

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                            • #29
                              popped off another arbor this morning, a JT4/MT4 from a 3/4" chuck. Same as all the others, drilled the chuck out to take a 3/8" pin, lightly closed the jaws on the pin, put the chuck in a thick wall piece of pipe and pressed it out with my 10T press. Took about 5 minutes. Now done a 14N, 18N and this LFA chuck successfully. Only the first 14N I did needed the arbor cut off and drilled out, but it was a nasty stub arbor anyway.

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                              • #30
                                Two days of effort with large sledge hammers, aerosol penetrating fluids by the case, and acetylene heat, yielded no results...no movement. I had heard about using a 50/50 mix of ATF and acetone, so as a last resort at the end of second day, we put a bunch of that mixture where it was stuck. Next morning we checked and the shaft was settled to the floor and slid out easily. We were just dumbfounded and made us believers.
                                Of course, you'd done a couple of days of softening up first, which might have made a difference. Also an overly pressed in taper is not the same as an overly pressed in straight displacement fit which is not the same as "rusted in place". Not to say that might not be a great mix, and I'll probably try it when it looks appropriate, merely that all stuck things are not stuck the same way, and the workable solution will need to take that into account.
                                "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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