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Calibrate old Starrett level?

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  • Calibrate old Starrett level?

    Old Starrett level lives in box shown. I want to use it to level a lathe and have watched oxtools interesting video on how to do incl calibrating the level first. However there isn't a glaring obvious tweaking knob to adjust this level. Obviously I'm missing something here. No I haven't checked it end for end as 'old Tom shows, and just assumed that all levels are begging to be calibrated. Pls explain this.

  • #2
    Looks lie there is a hinge on the top. Fat area at right end of pic.

    Might be something else, as a hiinge would not appear to work well as shown. But the base is cast, and the cover would come off for adjustment. Whatever it is is in pretty direct line with the cross-vial.

    I cannot quite read it, are you sure it is Starrett? Looks a bit like a different name, unit does not look very "Starrett like". Sensitivity seems to be 2.5 thou per div per ft.
    Last edited by J Tiers; 10-20-2016, 09:12 PM.
    CNC machines only go through the motions

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    • #3
      I agree with J Tiers. It looks like the top might flip open. If so the vial should have some adjusting screw on one end.

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

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      • #4
        You wouldn't need to calibrate the level to use it for adjusting your lathe in any case. What you're looking for on the lathe is "changes" to the reading. So, for instance, in looking for twist in the lathe bed you can move the carriage towards one end, set the level on it, and shim as necessary to get the bubble reading towards the middle. At this point it doesn't even have to be exactly centered. Just make note of where the bubble lies, crank the carriage down to the other end and see what's happened to the bubble. If there's no twist, the bubble will be in the same position.

        In the worst case, the bubble will have migrated so far towards one end that you can't be sure it hasn't pegged the end of the vial. If that's the case, you know there's a twist and you know the direction but don't quite know the magnitude. So, either start over, re-shim to move the bubble towards the opposite end in order to get the full reading, or just start adjusting the feet in the direction they need to go to straighten it out, and keep re-doing the test until it's straight.

        Similar procedure will map out longitudinal anomalies. You don't need any absolute level calibration, just knowing if the reading doesn't change or not.
        .
        "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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        • #5
          I have seen a starret level like that, the name is on the plinth, at the bottom, LS starret, Athol etc, I think I can just make it out, irrelevant I know, you still have to cal it, I'd go with the lid scinario, does look hinge like.
          Mark

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          • #6
            Originally posted by J Tiers View Post
            Looks lie there is a hinge on the top. Fat area at right end of pic.

            Might be something else, as a hiinge would not appear to work well as shown. But the base is cast, and the cover would come off for adjustment. Whatever it is is in pretty direct line with the cross-vial.

            I cannot quite read it, are you sure it is Starrett? Looks a bit like a different name, unit does not look very "Starrett like". Sensitivity seems to be 2.5 thou per div per ft.
            Enlarge my photo with fingers and u should be able to read company name and Athol, Mass in middle of shiny part at bottom.

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            • #7
              Here's an inverted view, looks like the thing's sealed up tighter'n a sardine can and there's no key, so it must have been intended to go without calibration. That makes sense, it looks like the bubbletube is potted in there for keeps.

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              • #8
                Shaft or Crank Pin level,there is no adjustment.What leads you to believe it's out of calibration?
                I just need one more tool,just one!

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                • #9
                  Looks like what we were thinking was a pivot or hinge is actually the plug for the side vial or the end of the vial tube enclosure itself.
                  If the bubble looks like it's bigger or longer than it should be it may be because some of the fluid has evaporated over the years.
                  I have an 8" Starrett machinists level where the bubble has grown in length.

                  It's easy to check to see if it's accurate....... you don't need a level surface to check it, just close to level will work. Set it on a close to level surface where the bubble is somewhat centered, get a good look at where the bubble hit's the marks and turn it 180 degrees and it should read the same, if it doesn't then it's off.

                  JL................
                  Last edited by JoeLee; 10-20-2016, 11:46 PM.

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                  • #10
                    If the bubble looks like it's bigger or longer than it should be it may be because some of the fluid has evaporated over the years.
                    Hard to understand how the liquid can evaporate from a sealed glass phial?

                    Regards Ian.
                    You might not like what I say,but that doesn't mean I'm wrong.

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                    • #11
                      It does happen. I've seen it a few times. Must be the end of the sealed vial dries, shrinks or absorbs some of the fluid over time and the bubble grows.
                      On my 8" Starrett when dead level the bubble is almost one graduation past the line with the dots on each side.

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

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                      • #12
                        Changes in atmospheric pressure would tend to cause it (bubble) to shrink or grow. By how much, I don't know.
                        Lynn (Huntsville, AL)

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                        • #13
                          Originally posted by lynnl View Post
                          Changes in atmospheric pressure would tend to cause it (bubble) to shrink or grow. By how much, I don't know.
                          And temperature. I was getting some level vials from a small manufacturer and the engineer had brought some out of storage. This was winter, and he commented that the bubble size would restore itself when they warmed up.
                          .
                          "People will occasionally stumble over the truth, but most of the time they will pick themselves up and carry on" : Winston Churchill

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                          • #14
                            I hate to point to an obvious, but Starrett is still in business, and you can call them.
                            Mike
                            WI/IL border, USA

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                            • #15
                              Some of the old levels had their vials set in plaster, like plaster of paris and adjusted as the plaster hardened. Any means of adjusting a level should be easy to see and carry out.
                              The museum mill is not quite level and we have the Moore and Wright level adjusted to suit for use with the sine bars.

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