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Dial Indicators; Removing the bezel

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  • Dial Indicators; Removing the bezel

    I had to do some work recently on three dial indicators I had put aside a few years ago.

    I thought I would share how the bezel and plastic lens comes off. I found three different methods of attachment and ended up practically destroying one trying to figure it out.



    One dial indicator was a cheap Chinese no name with a silver ring bezel where the pointer was rubbing on the graduation dial inside the lens. This caused the indicator to stick and drag.

    One (Fowler) had to have the plastic lens (aka crystal) replaced.

    One was a Starrett dial indicator where the graduation ring would no longer turn with the bezel ring, so you couldn’t zero the indicator.

    Also pictured are two (from “mhc” Industrial Supply). One with an aluminum (silver) bezel, and the other had a black plastic bezel.

    Fowler:
    The bezel ring is held on by three flanges which are screwed to the housing under the graduation dial. These flanges ride in the groove of the bezel ring.

    To change the plastic lens it is not necessary to remove the silver bezel ring. The lens is held in place in the ring by the two “limit indicators” similar to a snap ring. Remove the snap rings and remove the lens.

    Under the lens is a white plastic spacer that presses on the graduation dial. This pressure is what makes the graduation dial turn with the bezel ring.

    If you want to go further than replacing the lens and remove the silver bezel ring, you must back off the flange screws under the graduation dial and retract the flanges from the rings groove. When trying to get a screwdriver under the graduation dial, it would be best to first press the indicator plunger “in” to rotate the dial 180؛ away from the capture flange. You can retract the flange from under the graduation dial, or pry back the flange from inside the back of the indicator. (Mine were too tight to move unless I loosen the screws.)



    FWIW, I made my lens from a piece of plastic from an old “Bookers Bourbon” box. I cut out a small square, and used double stick tape to adhere it to a slug of aluminum in the lathe.

  • #2
    These are cheap Chinese (from “mhc” Industrial Supply).

    They are made by the same company, but are different. The one on the right (black bezel dial ring) was purchased several years ago, and the one left (silver bezel dial ring) was purchased recently. The new one is more cheaply made. The bezel is held in place by a tab flange that can be retracted by loosening the screw from inside.


    Inside the back of the silver bezel dial indicator, loosen the bezel tab hold down and slide it back out of the dial rings groove. The ring has a second hold down in the form of a tension spring captured in a groove. Also pictured are the photos from a dial indicator I almost destroyed trying to figure it out.

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    • #3



      Now looking inside at the Dial Indicator with the black bezel, you can note there is no indication of flanges as there were inside the Fowler, and no hold down tab to retract. Therefore you can conclude that the bezel ring is held on with three tension springs, (like the Starrett, which only requires that the dial cover be forced off. Make sure your pressure on the ring is 180؛ away from the pointer to prevent from bending the pointer as the ring comes off. This is only a guess, I tried to force it off, thinking it would pop off as easy as the Starrett, but it wouldn’t.

      Another side note, there is a difference to the quality of the bezel locking mechanisms. Some are poor and some are very good.

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      • #4
        Starrett

        The Starrett dial is held on with three spring wires set into machined slots, and the bezel will come off by pushing up under the ring. It just pops off.




        Inside the bezel contains the graduation dial, and a brass colored springy washer that keeps tension on the face of the indicator. You can see faint rub marks on the face where it rubs.

        Both the graduation dial and the springy washer have a notch which matches to a very small tit on the bezel ring. The graduation dial on my indicator had slipped out of the notch, and therefore would not turn with the bezel ring.


        I aligned the two notches, but they kept slipping off the tit, so I used a small strip of double stick tape to hold them together at the notch. Works fine now.

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        • #5
          This is an excellent guide, thank you for posting!

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          • #6
            That is very useful, thank you. Who knew getting the crystals off could be such a chore. I have a couple of Fowlers, one needs a crystal and the other needs polishing.

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            • #7
              A useful guide not for normally thought of task. I have one badly stained lens I should replace.
              Just a thought - perhaps the tension spring types can be released with a shim inserted under the flange and pushed round to depress the spring. I doubt they are meant to just pop off easily as one of yours did.

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              • #8
                Top marks for the information and excellent pics!!

                Thankyou very much.
                I don't need it now but I'm sure I will in future.
                Mike

                My Dad always said, "If you want people to do things for you on the farm, you have to buy a machine they can sit on that does most of the work."

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                • #9
                  Originally posted by Baz View Post
                  A useful guide not for normally thought of task. I have one badly stained lens I should replace.
                  Just a thought - perhaps the tension spring types can be released with a shim inserted under the flange and pushed round to depress the spring. I doubt they are meant to just pop off easily as one of yours did.
                  I tried that.

                  I used a .0015 shim and tried to work it under the ring. No luck, it was too tight to get under the bezel ring. With anything thinner, I don't think it would have been strong enough to depress the spring.

                  The more I thought about it, I was trying to push it off at the wire spring locations. Perhaps it would have been better to try pushing at say about 10 o'clock, assuming the springs are in the same locations as the Starrett. If there ever comes a time, I really need to get it off, I WILL get it off, (It might not work after that) but I WILL get it off.

                  I am hopeful the photos will give people a head start if they have to get into theirs. I tried to find something on the web about how to do this and I couldn't find anything.

                  Edit;
                  If I have to try something else, I think I will drill a hole the size of a paperclip in the bezel at the level of the spring, then identify the outward most spring. Then with a paperclip, I will depress the spring and the bezel should pop off. Just thinking.
                  Ron
                  Last edited by Ron of Va; 01-26-2014, 07:20 PM.

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                  • #10
                    I’m impressed that the innards look distinct from each other - no common manufacturer merely putting a brand-name face on them.

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                    • #11
                      Thanks much for the impressive posting and great pics.

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                      • #12
                        Ron,

                        You might want to look at this site. This is a local fellow and he posted it several years ago, it is a neat way to put a new replacement crystal in. He uses lexan, cut from a sheet.

                        http://www.d-and-d.com/PROJECTS/Crystals/index.html

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                        • #13
                          Thanks for the info.

                          I re-read the original post so hope I did not miss something, in all of the examples, you did not have to use some sort of press to replace the crystal?

                          Just wondering as I distinctly remember a note from Long Island Indicator about using a press to replace a crystal. I thought all would need this, other than perhaps the cheapest of cheap but it may have only been one particular maker or several particular indicators.

                          Edit: a bit of an aside, the Long Island Indicator website is an interesting read, as is their Facebook page (I almost never go to Facebook), lots of info...but lots of similar notes, who knew there could be so many variations on a theme
                          Last edited by RussZHC; 01-26-2014, 09:38 PM. Reason: Another note

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                          • #14
                            Originally posted by RussZHC View Post
                            Thanks for the info.

                            I re-read the original post so hope I did not miss something, in all of the examples, you did not have to use some sort of press to replace the crystal?

                            Just wondering as I distinctly remember a note from Long Island Indicator about using a press to replace a crystal. I thought all would need this, other than perhaps the cheapest of cheap but it may have only been one particular maker or several particular indicators.
                            Russ
                            Many lenses require a press (or something similar) to replace the crystal (lens) in the bezel ring. Those can be identified by their domed shape. A jig has to be fabricated to press the lens into the ring. I have replaced a couple of them in some Starrett dial calipers. Not yet into a dial indicator. When the time comes I will have no problems there.

                            The lens in the Fowler that needed replacement was a flat lens. Therefore no special pressing jig was needed.

                            In the past I fabricated a jig using a jury rigged base allowing for the dome, and a piece of a wooden dowel held stagnant in a drill press. Pushing the new lens into the ring is a piece of cake, provided you have the right jig. I didn’t take any photos of the procedure.

                            But you have to get the bezel off, before you can replace the crystal. Crystal replacement is another topic.

                            I would show off my jig, if I still had it. But it’s long gone.

                            I am glad the original post was helpful.

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                            • #15
                              If you go to the site I provided you will see the tools he made to press in the lexan which results in a slight doming effect.

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