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  • Alternative thrust bearings

    I am using the flat captive needle thrust bearings with ID 0.875 and OD ~1.5" between two 0.032" thick washers above and below an
    acme nut bolted to a bicycle chain ring ~7.5" OD that is captive between two plates. This is driven by a garage door opener and drives an acme screw up and down lifting about 300#.
    Trial assembly and operation resulted in a lift of about a foot before noises lead to discovery that the top washer and thrust bearing had disintegrated. I wanted 0.0625" washers but local source only had 0.032". Maybe 0.090" would be better. The acme screw goes through a bronze flanged sleeve at top and bottom with the thrust bearings and washers between the acme nut and the bronze sleeves. Question is what alternatives to the needle bearings are advised? Just plain bronze oil impregnated washers? Something else? Is this way too much weight for $3 flat needle thrust bearings? Rotational speed is maybe 20rpm +/- 10rpm.
    Steve

    [This message has been edited by sch (edited 02-02-2006).]

    [This message has been edited by sch (edited 02-02-2006).]
    Steve

  • #2
    A tapered roller wheel bearing should work. Cheap. Try a utility trailer wheel bearing for a few bucks.
    Free software for calculating bolt circles and similar: Click Here

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    • #3
      Yeah, I think the tapered roller bearing might be your best bet. They aren't too grand with axial loads either but they should hold up better than the flat needle bearings.

      You might think about adding a stop to the tapered roller bearing too. A sort of pre-load adjustment.

      Also note that needle bearings need a smooth hardened surface to run on. If your "washers" were stock hardware, that would cause a failure.

      Comment


      • #4
        Probably do better with hardened washers thick enough to not bend over the edge of of the bushing flanges. (I'm ass uming the flanges are smaller in dia than the thrust bearings).

        On the other hand, altho the oil impregnated thrust washers have more friction than The rollers, they will support more weight and are more forgiving. Could try using the the flanges on the bushings with the washers you have to take up the space.

        BC
        BC

        If ya wannit done your way ya gotta do it yourself.

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        • #5
          How about the thrust bearings from the kingpins on a solid front axle?
          Location: Saskatoon, Saskatchewan, Canada

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          • #6
            It only has to take 300 pounds. That's well within wheel bearing axial capacity.
            Free software for calculating bolt circles and similar: Click Here

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            • #7
              Thanks for the opinions. The washers used were ones designed to work with the flat needle bearings. Not sure which failed first, the top washer or the needle bearing
              but clearly the flat needle bearing is NOT designed for that load, on consideration.
              Taper bearings would certainly handle the load but require some juggling of the GDO mount as I have found that the chain drive doesn't tolerate more than 1-2mm of height
              variance. I suspect the bronze oil impregnated washer would be the best first start, with the taper rollers as a back up plan. Thanks.
              Steve

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              • #8

                300# is hardly anything. It sounds like the needle bearings would have worked, but maybe there was a little bit of dirt/grime/grit or lack of high temp grease? Did you inspect the ruined needle bearings closely for foreign material? What type of material/finish was on the .032" washers?

                -Adrian

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                • #9
                  Sch,

                  These ID 0.875", OD 1 7/16" Needle Thrust Bearings from MC Master ( http://www.mcmaster.com ) (Item# 5909K34) are rated for 2900#. The 1 11/16" OD version (Item# 5909K35) is rated for 4400#.



                  If the thrust washers that you used didn't have a bearing surface/finish on them, then they will just chew themselfs up which sounds like what happened?

                  -Adrian

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                  • #10
                    Super cheap thrust bearings for light duty -- use two grade 8 washers face to face like this: )( & a little grease.

                    20 rpm w/300#s may be too much, but may not be if for only ocasional use.

                    Let it fly!
                    uute

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                    • #11
                      3phase: Those are what I used, sourced locally from Motion Industries and IIRC were INA brand. I don't think Motion sells junk.
                      The top washer cracked and two pieces broke off one about 6mm, other 3x12mm and I suspect these broken pieces chewed up the needle bearing. AFAIK they were clean and well lubed. From your figures, it should have been ok. Hmmm.... More head scratching, at least they are cheap. I can't imagine heat being a problem in 1-2minutes operation at 10-20rpm. The washers are ground and sold with the bearings.
                      Steve
                      Steve
                      Steve

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                      • #12
                        Steve,

                        I've used the same bearings that Adrian showed, made by INA, with no problems at higher loads and speeds. They're quire good. Were your bearing surfaces parallel?

                        ------------------
                        Leigh W3NLB
                        Leigh
                        The entire content of this post is copyright by, and is the sole property of, the author. No assignment
                        of title nor right of publication shall ensue from presentation of this material on any computer site.

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                        • #13
                          How bout support behind the washers, were they just riding on a flange orount the ID, or supported full width of washer (to OD)?

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                          • #14

                            Maybe you grabbed the wrong can? Do you keep your valve grinding compound next to your can of bearing grease?

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                            • #15
                              Wherever possible I would use a normal single row radial ball bearing. This may not been in the design books, but...

                              they are cheap, readily available, will do the job and especially because they are SEALED.

                              Taper rollers, needle rollers, plain bearings etc all have the same problem - how to keep them clean (plus comparitively expensive).

                              No doubt you will say that this is a thrust situation, but (from memory) a radial ball bearing will handle about 1/3rd of its load as thrust (correct me if I am wrong).

                              And this is only about 300 lbs, so a 7/8" bore bearing should be fine.

                              Also, though a bit bulkier, the self aligning type of bearing is worth considering - these are made for conveyors and the like, they are a housing and bearing combined, ideal when things aren't quite lined-up! (Which is a possible reason for the problems).

                              The cheapest type have pressed steel housings, the heavier type use a cast iron housing. Available in flange mount style for this sort of application.

                              Any comments or criticism?

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