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  • Rattle in my head

    So, I've got a 2 year old bridgeport clone that's starting to develop a rattle in the head. It's a variable speed, 3 HP, R-8. Its especially noticeable at lower speeds and seems to go away above 1200 or so.
    It was nice and quiet at all speeds when it was new - I haven't really used it all that much, maybe 100 hours or so.
    I shoot some grease in the grease nipples once in awhile, oil in the oil cups etc. I don't think I've abused it. A couple little "crashes" but that happens to everybody now and then .... doesn't it
    Advice, comments ?
    Thanks

  • #2
    Cousin???

    Thought I had found my cousin, my nose after being broke 13 times in one year rattled when I would shake my head. It's locked up with snot and allergies now.

    My bridgeport rattled while running on a phase convertor, runs smooth on a vfd.. they make a bushing to go around the splines in the top end.

    Load a test bar in the spindle and check runout.. one crash does ya..

    A bridgeport has two bearings on the bottom, one on top of the cartridge.. they usually bend right above the bottom two bearings. I have hunted one for my machine now for two years. too cheap to pay industrial prices..
    Excuse me, I farted.

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    • #3
      No rattles but both my eardrums are perforated and when I sneeze they squeak.

      Here in my gallery is a cutaway diagram of a Bridgeport head:

      http://ixian.ca/gallery/displayimage...lbum=14&pos=18
      Free software for calculating bolt circles and similar: Click Here

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      • #4
        That drawing is for a step pulley head, and not much help for a vari speed head. The bushings on the vari speed sheaves get worn and cause the rattle described.

        If caught in the early stages, the fix is not too difficult and involves replacing the plastic bushings. If allowed to continue, the motor shaft will wear to the point that one of Sir John's weld and machine repairs will be required.
        Jim H.

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        • #5
          I put a .001 DTI on the spindle after my latest little "incident" and can barely see the needle move, so I don't think its spindle bearings.
          Yes, the rattle seems to be coming from up top somewhere and I had read one of "Sir John"s" threads about repairing the shafts. I am thinking its probably the sheave bushings, I'm thinking its still early too and if I do it now the shafts are probably still OK.
          Why would they put plastic bushings in there ? I guess I already know the answer to that. Does anyone make a better bushing that'll last more than 100 hours of use ?
          Is this much of a job ? Does the motor need to come off ? It looks like a heavy sucker and way up there too !

          Comment


          • #6
            It depends on what size you need. I have some ultra hard bronze on hand and it won't cost much to send you a chunk if that will do. Just tell me how big a piece you need, I have plenty.
            Free software for calculating bolt circles and similar: Click Here

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            • #7
              Some of the Bridgeport clones use the Bridgeport style plastic wear sheaves that are reasonably easy to replace. Some of the other ones use a bronze on steel for the pulleys and I have seen several that have worn the motor shafts as well as the bronze, making repairs that much more complicated. If you get in it and find too much wear or it is not feasible to make repair parts, you can go with a fixed belt arrangement and use a VFD for speed control. Between back gear and a decent VFD, you can cover almost all of the speed range that you had before.

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              • #8
                there may be a screw at the top of the motor housing

                that adjusts the belt alignment - worth a try

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                • #9
                  Originally posted by JCHannum
                  That drawing is for a step pulley head, and not much help for a vari speed head. The bushings on the vari speed sheaves get worn and cause the rattle described.
                  Jim's right on, as usual. That's almost certainly the vari-speed bushing. If you let the sliding bushing wear too much, it will damage the sheave key and shaft, and then you'll have to send it to Sir John so he can MIG it back up and turn it smooth

                  It's a relatively simple repair, but you need to determine if your clone uses a Delrin or Bronze sliding bushing. Bridgeports use Delrin. Lagun, Index, Excello use bronze. The clones are a toss-up.
                  "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                  • #10
                    Here is an exploded view and price list for the top housing.

                    http://www.icai-online.com/home.php?cat=263

                    And a very reasonably priced repair kit:

                    http://www.icai-online.com/home.php?cat=312
                    Free software for calculating bolt circles and similar: Click Here

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                    • #11
                      Originally posted by Evan
                      Here is an exploded view and price list for the top housing.

                      http://www.icai-online.com/home.php?cat=263
                      The plastic VariDiscs that Mike mentioned are part number 59, but that's specific to the Bridgeport varispeed.
                      "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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                      • #12
                        David; 13 times in one year ? Hockey ? Yappin when ya shoulda been listenin ?
                        Evan; thanks for the offer, I don't think I'll take it apart this week, I'm kinda in the middle of something, maybe in a week or 2 or 3, that motor looks heavy.
                        Thanks for the replies .

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                        • #13
                          No rush here. If you want some bronze just say so. I have about 50 lbs of it.

                          According to David his nose got in the way quite a few times because it was paid to. He was a bouncer at one time.
                          Free software for calculating bolt circles and similar: Click Here

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                          • #14
                            It will depend on the manufacturer whether the bushings are bronze or delrin. The plastic bushings are quite thinwalled, and would require modifying the sheave to replace with bronze if you go that way. An added level of difficulty is the key in the sliding sheave, it has a cast in pin to locate it. Some provision for that would need to be made as well.

                            That is the downside of the vari-drive B'ports & their clones. The key is usually the first to wear, then the sleeve. It is recommended to run them through their range once a day for this reason. You are better off with a step pulley and VFD for about the same investment.
                            Jim H.

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                            • #15
                              The varispeeds were much sought after a few years ago but with the improvements in inverter technology if I had to choose now days I'd go for a step speed and VFD drive.

                              I get two types of repair in quite regular, One is the varispeed drive, weld and cobble up and the latter is fitting an oversize motor to a step speed.

                              I get more of the former.

                              .
                              .

                              Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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