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  • Bearing Race ID Help Please......

    A friend of mine gave me an older used bearing race. It measures 10 1/2" on the OD. The only marking on the race are BVGB and opposite that 29426. I'm guessing that's the part number.
    I have no idea who the mfg. is. I couldn't find any reference to either markings. This was used on some big electric motor.

    My intended use for this is for tramming my BP. It's the perfect size for the table. I've been looking for something like this for quite a while. I even bought a new brake rotor but decided not to use it. This race has a little surface rust on it. I cleaned some of it so I could indicate it for flatness on the surface plate So far from what I can tell it's within .0001 all the way around. Tapers slightly towards the center. Just curious what the cost of a new one would be.

    I can post some pics tomorrow if that helps with the ID. ID meaning identification. Messed up on the title too. Can't edit that.

    JL..................

  • #2
    Does it look anything like the one in this photo?:

    https://www.vxb.com/29426-Spherical-...85-p/29426.htm

    A bit pricey to go out and buy one, but if there's an outer race available that's still in good condition, then that large flat, hardened outer race ring is a great tool to use when tramming the head of a BP.

    Comment


    • #3
      Totally superfluous.
      Don't understand the attraction to something like this for indicating.
      Usually stored hanging on pegboard hooks.

      -D
      Last edited by Doozer; 01-06-2021, 11:29 PM.
      DZER

      Comment


      • #4
        It's nice if your table happens to have t-slots......

        But if you do the right thing and only deflect the indicator a few thou, the ball or "foot" passes them just fine.
        2801 3147 6749 8779 4900 4900 4900

        Keep eye on ball.
        Hashim Khan


        It's just a box of rain, I don't know who put it there.

        Comment


        • #5
          That's what I usually do, and I've occasionally floated the indicator stylus above the table and used a small ground block to slide under the indicator so that it only deflects the indicator by a few thousandths. Usually do that when the machine table is in very sad shape and the indicator needle would be bouncing all over the place otherwise.

          Comment


          • #6
            Originally posted by tom_d View Post
            Does it look anything like the one in this photo?:

            https://www.vxb.com/29426-Spherical-...85-p/29426.htm

            A bit pricey to go out and buy one, but if there's an outer race available that's still in good condition, then that large flat, hardened outer race ring is a great tool to use when tramming the head of a BP.
            That looks like the race.

            JL....

            Comment


            • #7
              Originally posted by eKretz View Post
              That's what I usually do, and I've occasionally floated the indicator stylus above the table and used a small ground block to slide under the indicator so that it only deflects the indicator by a few thousandths. Usually do that when the machine table is in very sad shape and the indicator needle would be bouncing all over the place otherwise.
              I've always slid a ground block around under the indicator too. It works OK. I just wanted something for a continuous sweep.

              JL......

              Comment


              • #8
                for really indicating right on an old table i have used a big piece of float glass with a thin sheet of soft foam under it. its surprisingly accurate as checked on a surface plate. the table had hills and valley and this was a good way to average them out.

                Comment


                • #9
                  There is a larger button tip with plunger type indicator set for crossing voids. Worked great for crossing sharp keyways when doing shaft alignments. Works when indicator is depressed .020".

                  Comment


                  • #10
                    Tee slots do not matter.
                    Only preload your indicator 5 or 10 thousandths
                    so the needle drops just that amount.
                    If you took a 10" bearing race out of your toolbox
                    and plunked it on a mill table in a for-profit machine shop
                    you'd get laughed out the door.
                    But your shop, your rules.
                    Sometimes I swipe the vise to tram the head if I
                    am in a hurry. Not a big deal.

                    Now to be fair, I admit I did try to use a bearing race once
                    to tram a mill. I was at work, and I found a huge Timken
                    race in the trash, from the maintenance department.
                    It was 6 or 7" OD. So I tried it on the Bridgeport table.
                    I gotta tell you, I spent more time keeping the race centered
                    in the sweep arc path of the indicator. Unless I had my
                    indicator linkage set to pretty much the exact radius of this
                    bearing race, the tip of the indicator was constantly falling off.
                    That then and there I realized using a bearing race was more
                    effort than it was supposed to save. I chucked it back in the
                    trash and moved on with life.

                    -D
                    Last edited by Doozer; 01-07-2021, 01:29 PM.
                    DZER

                    Comment


                    • #11
                      Here is a pic of the race. It's the perfect size for the table and the dia. covers the footprint of the base of the vise.
                      I'll have to clean it up a little more and check it again.

                      I've always slid a ground block around under the indicator but it would be nice to just be able to sweep the dial 360 deg. continuously.

                      JL.................

                      Click image for larger version

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                      Comment


                      • #12
                        Originally posted by Doozer View Post
                        Tee slots do not matter.
                        Only preload your indicator 5 or 10 thousandths
                        so the needle drops just that amount.
                        If you took a 10" bearing race out of your toolbox
                        and plunked it on a mill table in a for-profit machine shop
                        you'd get laughed out the door.
                        But your shop, your rules.
                        Sometimes I swipe the vise to tram the head if I
                        am in a hurry. Not a big deal.

                        -D
                        The only one who is going to laugh me out of my shop is me. and that has happened.

                        JL........................

                        Comment


                        • #13
                          Originally posted by dian View Post
                          for really indicating right on an old table i have used a big piece of float glass with a thin sheet of soft foam under it. its surprisingly accurate as checked on a surface plate. the table had hills and valley and this was a good way to average them out.
                          That would be calibrated thin foam?

                          Sounds like you have added several variables.

                          Do what I, eKretz, and Doozer said. Just a few thou deflection on the indicator and there is no issue.

                          Keeping the indicator centered.... LOL.... that's the issue, and then don't get any grit under that bearing race, etc, etc. Indicate the table directly and you KNOW!
                          Last edited by J Tiers; 01-07-2021, 02:37 PM.
                          2801 3147 6749 8779 4900 4900 4900

                          Keep eye on ball.
                          Hashim Khan


                          It's just a box of rain, I don't know who put it there.

                          Comment


                          • #14
                            I don't understand the need to use a plate of some sort to indicate the face of the table. The face of the table is as close as you can get to be accurate. The more layers between the indicator and the table is the more likely to be off.
                            Sarge41

                            Comment


                            • #15
                              Originally posted by sarge41 View Post
                              I don't understand the need to use a plate of some sort to indicate the face of the table. The face of the table is as close as you can get to be accurate. The more layers between the indicator and the table is the more likely to be off.
                              Sarge41
                              Idea being that the machine table probably has many imperfections from years of use (and occasional abuse) in addition to the T-slots which cause the indicator to bounce around a bit when tramming the head. Inserting the smooth surface of this bearing race helps to save on unnecessary indicator wear. When spot checking a machine that has a good table surface it's quick and easy to set the indicator to only deflect a few thousandths, so the needle won't bounce too much. It's when the head is way out of tram, or the table is pretty banged up, that the introduction of the smooth surface might be needed. On my worn out old machine I've stoned down the high spots caused by previous owner's activities, but there are sufficient number of divots that I use a pair of 1"x2"x12" parallels to give me a smooth indicating surface.

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