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Bearing Race ID Help Please......

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  • #16
    Originally posted by J Tiers View Post

    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!
    I don't believe that there is any foam that is flat enough to use for this purpose. It changes with temp and humidity. Glass is no where near perfect, even good quality glass.

    All around a bad idea to stack such materials for precise measurings.

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

    Comment


    • #17
      Originally posted by tom_d View Post

      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.
      Your correct. My table isn't as bad as some but it has a few nicks here and there. Even the scraping will cause my tenths dial to flutter. Dropping off into a T slot and then back up on the table causes my dial to never return to where it was on the other side of the slot. It's best to keep it loaded throughout the entire sweep and to have a smooth surface so the dial doesn't flutter. That bearing race is perfect.

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

      Comment


      • #18
        Try this it helps.
        use DTI in Indicol or other holder that allows needle to sweep approx 6 inch circle.
        now my table is frosted so in between those marks, I can see if there is wear or damage. .. make a sharpie mark in 4 locations you deem good.
        now you want indicator needle tilted to about 15 to 25 degrees to table. Now use indicator travelling in a direction where the needle is trailing.
        now it rides over the tee slots or holes easily .
        Once used to it , gets easier... get it to 1/2 thou... it's a thou over a foot.. good for 97 percent of work.

        Comment


        • #19
          Thats exactly what I have done with bearings from a helicopter output shaft. Brand new and somewhat pricey, about 10 times the commercial cost. I have a drawer full of inner and outer races from 1" to 12" diameter. Perks from museum stock.

          Comment


          • #20
            Originally posted by JoeLee View Post
            ..... Dropping off into a T slot and then back up on the table causes my dial to never return to where it was on the other side of the slot....
            JL..................
            Problem with the indicator
            or flex in the linkage arm.
            Seriously, I had an Alina
            indicator that was flakey
            like that. Sent it to MR
            Tool Repair, fixed it for $20.
            Check out what you have.
            Skipping over the slot
            should absolutely never
            be a problem. For real.

            -Doozer
            DZER

            Comment


            • #21
              I put an indicator in the end of an arm mounted in a collet. The arm is about 9 inches long, so the swing from one side of the table to the other is about 18 inches. Adjusting the table itself with that to as close as I can get it is surely as good as adjusting to a more precise surface that is less than half that distance, yes? And yes, the T slots can easily be dealt with.
              "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

              Comment


              • #22
                Originally posted by mickeyf View Post
                I put an indicator in the end of an arm mounted in a collet. The arm is about 9 inches long, so the swing from one side of the table to the other is about 18 inches. Adjusting the table itself with that to as close as I can get it is surely as good as adjusting to a more precise surface that is less than half that distance, yes? And yes, the T slots can easily be dealt with.
                You mean like this ???? Been doing it this way for years.


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

                Comment


                • #23
                  Originally posted by Doozer View Post

                  Problem with the indicator
                  or flex in the linkage arm.
                  Seriously, I had an Alina
                  indicator that was flakey
                  like that. Sent it to MR
                  Tool Repair, fixed it for $20.
                  Check out what you have.
                  Skipping over the slot
                  should absolutely never
                  be a problem. For real.

                  -Doozer
                  I don't use my Starrett flex post for tramming. I try to keep it as rigid as possible.

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

                  Comment


                  • #24
                    All I can say is your method with 1/2 the arm stick out would work well with needle turned 90 degrees ,and running only one direction.
                    but.. and this matters. .. it takes a few times... for it to get comfortable and fast...
                    turning the indicator will help huge unless you are using the ring..

                    Comment


                    • #25
                      Originally posted by 754 View Post
                      All I can say is your method with 1/2 the arm stick out would work well with needle turned 90 degrees ,and running only one direction.
                      but.. and this matters. .. it takes a few times... for it to get comfortable and fast...
                      turning the indicator will help huge unless you are using the ring..
                      Well, with the block under the needle the needle never slides on anything, I slide the block around under the needle so it doesn't make any difference which way it sits. It's just a pain. The ring would make it a lot easier.

                      That 1/2" bar does have a little flex to it, maybe it's more the 1/2" shank going into the collet.
                      I've always wanted to make a new bar, preferably something that is arched, like one of those camel back things. I also would go to a larger dia. shank. like 3/4"

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

                      Comment


                      • #26
                        What 754 mentioned is a good tip that I forgot, the one about turning the indicator 90 degrees and running one direction. I can see using a plate such as the bearing race when "roughing it in", but then I go to the indicator on the table itself. That way, there is no surprises.
                        Sarge41

                        Comment


                        • #27
                          Originally posted by JoeLee View Post
                          ........................ Dropping off into a T slot and then back up on the table causes my dial to never return to where it was on the other side of the slot. It's best to keep it loaded throughout the entire sweep and to have a smooth surface so the dial doesn't flutter. That bearing race is perfect.

                          JL..................
                          Going into a slot and BACK to same point? Or going into a slop and up the other side of it?
                          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.

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                          • #28
                            Originally posted by sarge41 View Post
                            What 754 mentioned is a good tip that I forgot, the one about turning the indicator 90 degrees and running one direction. I can see using a plate such as the bearing race when "roughing it in", but then I go to the indicator on the table itself. That way, there is no surprises.
                            Sarge41
                            Yes, it is a good tip. If I'm moving my indicator along something back and forth I always try to have the needle in line with the travel and not 90 deg. to it.


                            But in my instance with the block under it the indicator never really moves on the block. I keep it under the needle as I sweep the table.

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

                            Comment


                            • #29
                              Originally posted by J Tiers View Post

                              Going into a slot and BACK to same point? Or going into a slop and up the other side of it?
                              Either way. But were talking a tenth or so.

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

                              Comment


                              • #30
                                So you are chasing a tenth of repeatability and you think a bearing race in between is going to get you that tenth ?
                                Take a toke and pass it over to me. You must buy the good stuff. LOL

                                -D
                                DZER

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