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  • Baldor bearing removal?

    The Baldor 7200 spins well, but bearings are noisy, so they will get replaced.

    It looks like they are pressed on the shaft up to a shoulder, and a collar that drives the inner wheel washer is pressed on after them. The slot in teh collar meshes with a bump on the inner collar.

    Aside from a brute force pulling of the bearings, is there any trick to getting these off? The collars do not appear t be threaded, and shouldn't be, to transmit torque. I;ll have to make a puller collar to avoid poking right through the bearings with the puller hooks.... no bearing puller this small

    newer units than this old 7200 are made differently. These have a through-bored hole, with a retainer, and the pressed on bearings with collar





    It also has an odd two-piece washer not typical on cheaper units....

    Last edited by J Tiers; 07-31-2014, 09:51 PM.
    CNC machines only go through the motions

  • #2
    I'm almost thinking the collars are threaded, but they don't seen to want to come off..... might help if I knew if they were RH or LH threads.... Baldor seems to have forgotten they made this one, so far no repair part list that is for a grinder like this.

    Threaded makes sense for some of the situation, not for other parts. It would be natural to thread them to snug up bearings. But not so cool to thread them since the inner wheel washers are driven by them.... or at least they have little dimples that fit into the recess... That added twisting force might tend to unscrew them, or tighten the washers up on the wheels, neither of which is likely to be a good idea.
    CNC machines only go through the motions

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    • #3
      Arbor Press or Split Bearing puller

      Edit:

      Read your second post... If threaded on then one will be right hand the other will be left hand.
      Mike
      Central Ohio, USA

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      • #4
        You might try putting the shaft vertically between vise jaws or something similar and dropping the whole thing so the bearing would hit the jaws and drive it off. Two pieces of flat metal and two long bolts with nuts will make you a puller if you make a slot in one piece to get it behind the bearing. Be sure that one is substantial enough with the slot cut in it.

        That two piece washer kinda looks like a balancer of some sort.
        Don Young

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        • #5
          Without some inside information, it will take some detective work.

          The slot in the end of the sleeve almost looks like it was also designed to engage a wrench (hook spanner)? Have you tried turning the sleeves?

          Or tried heating the sleeves to see if they pull or screw off?

          Worst case scenario would be to burn one of the bearings off with a torch, it would probably be apparent then if the sleeves are pressed or screwed on. It can be done without scarring the shaft, however YMMV.



          Dave

          Edit; Maybe less dicey than the torch method, set it up in the lathe and using a parting tool, cut away the end of
          the sleeve where it meets the bearing. This would relieve pressure against any threading and should allow it to unscrew if the nature of the beast is such. If not, you are back to trying to pull or heat and pull.
          Last edited by becksmachine; 08-01-2014, 12:54 AM.

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          • #6
            Originally posted by Ohio Mike View Post
            Arbor Press or Split Bearing puller

            Edit:

            Read your second post... If threaded on then one will be right hand the other will be left hand.
            A gear puller with a collar didn't so much as budge it.... at least not when tightened as much as I considered safe in case they are actually threaded. I now suspect more strongly they might be threaded, but no evidence of loosening that way either.

            Have not completely decided if the threading (assuming there is any) would follow the "handedness" of the spindle ends, or be opposite... Spindle ends are of course opposite, set so as to tend to tighten when drag is on the wheel. Most likely the collars, if threaded, would be the same way, since they would only tighten against the bearings.

            I need to make a real keyed wrench to avoid screwing up the recesses any worse than they were to begin with.

            If they are not threaded, there is no harm in trying to unscrew them. If they ARE threaded, there is plenty of harm in trying to pull the whole works off.
            CNC machines only go through the motions

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            • #7
              Looking at the notch in the first picture, there appears to be a groove and possibly a seam. Is it possible the section of shaft to the right is a separate threaded
              piece holding the collar on?
              Location: Long Island, N.Y.

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              • #8
                Originally posted by RichR View Post
                Looking at the notch in the first picture, there appears to be a groove and possibly a seam. Is it possible the section of shaft to the right is a separate threaded
                piece holding the collar on?
                No, I do not think so..... I'd call that impossible....The shaft goes UNDER the collar with a visible space. The collar retains the bearing, and drives the washer, but it is pretty definitely separate.

                It would also be a strange way to make a shaft that you want to be concentric right through to avoid vibration. I'd want it to be a single piece with no "variables", and I bet Baldor would agree. Wouldn't be the first time someone designed a piece differently from how I would, but I don't think that would be my first guess here.

                This morning (day off due to excess vacation) measuring, and checking the specs on 6203 2R5 bearing, it is 17mm bore. the exposed shaft is 0.625" diameter (15,87 mm )

                The difference between those is about 1,125mm, and I can see a section of unthreaded larger shaft diameter under the notch in the collar, that appears to be roughly a 0,5 mm step-up. (You can see it too, it's in one of the pictures) I would call this as pretty much impossible that any thread could be present to hold the collar, and it is just plain pressed-on. Not enough room between the diameters.

                Looks like it simply comes down to pulling the bearings with the collars. But I'll likely split the races before those collars move.... they are stuck on for fair. And no way to get behind them, the collars are already the diameter of the inner race, the shoulder is a bit bigger.
                Last edited by J Tiers; 08-01-2014, 10:41 AM.
                CNC machines only go through the motions

                Comment


                • #9
                  Originally posted by becksmachine View Post

                  The slot in the end of the sleeve almost looks like it was also designed to engage a wrench (hook spanner)? Have you tried turning the sleeves?

                  Or tried heating the sleeves to see if they pull or screw off?
                  Tried unscrewing, no dice. Also decided there was just no room for threads within the 17mm max diameter that allows the bearing to come off.

                  heat, not yet. have to take it out to the other shop to do heat....
                  CNC machines only go through the motions

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                  • #10
                    Agreed that they are probably not threaded. They also don't appear terribly difficult to fabricate replacements. I would simply turn at least one off and go from there.

                    Is the two piece washer a flange washer for the grinding wheel? If so it is possibly for fine tuning balancing of the wheel.
                    Jim H.

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                    • #11
                      That's a bear. It is just that kind of situation that has kept me from eagerly digging into the nice old grinder I recently acquired.

                      Freeze it and then heat the collar with a torch? Of course you'd still need a way to grip it. Seems like someone out there must have encountered this style and would have tips. Send a photo to Baldor?

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                      • #12
                        Weld on another grip collar or ears to pull with. Turn it off in a lathe later.

                        if that doesn't work for you, mount the entire rotor in a lathe and turn of the collar. It will release before getting down to the shaft (you can leave a gripping collar if you want to pull it). Remove the bearing with a split bearing puller. Make new collar as required.
                        Last edited by lakeside53; 08-01-2014, 06:13 PM.

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                        • #13
                          We may get to turning off the parts... but I normally find that the need to do that either means 1) you gotta get it done now (not true here) 2) you have no clue what you are doing, and don't know the right way.

                          So I prefer to leave it for last.... that and the "blue wrench"....
                          CNC machines only go through the motions

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                          • #14
                            If the collar is truly frozen on, you have limited options and may have no other choice (and it's quick and low change of damage to other parts). It's obviously not supposed to be on hard, but it is. The bearing will come of (after the collar is removed) easily in comparison. I have never had a bearing that "won't" come off with the correct tools and pressure, although sometimes it requires a decent impact driver.

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                            • #15
                              Originally posted by lakeside53 View Post
                              If the collar is truly frozen on, you have limited options and may have no other choice (and it's quick and low change of damage to other parts). It's obviously not supposed to be on hard, but it is. The bearing will come of (after the collar is removed) easily in comparison. I have never had a bearing that "won't" come off with the correct tools and pressure, although sometimes it requires a decent impact driver.
                              Actually, I expected the collars to be stuck on pretty well. They have torque applied to them, and should not spin easily, since there is a dimple on the inner wheel washer that is intended to fit into the cut recess, to drive and stabilize the wheel against rotation vs the shaft.

                              Then also, these have probably never been off the machine since sometime between 1955 and 1980s. At least the style of the 1980s units is the new style, unlike this, and the 1955 units have the same constructional style as mine, but model numbers lower than this. So I figure those dates bracket the build date. In any case, I doubt anyone ever took it apart.

                              So the collars being stuck are absolutely no surprise. Paint, rust, an original press-fit, all factors in their being tight now.

                              I figure the Bubba techniques are to be left for later.
                              CNC machines only go through the motions

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