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  • Gage blocks

    I made the mistake of looking first at Starrett and immediately was struck down with the vapors by their prices.
    Well worth it I don't doubt but, it ain't me babe.
    SO, can one expect decent results from imported gage blocks in, say, the sub $200 range?
    Many state they are in compliance with some sort of testing agency.
    Len

  • #2
    First off, what are you going to be using them for? If just in the home shop, just about anything you buy (as long as they're in good shape) will be plenty good enough for anything you're likely to be doing. Personally, I bought good condition used stuff. Got a few sets. Pratt & Whitney square blocks, and both Weber and Mitutoyo rectangular. The Mitutoyos are in the best shape, I keep those for inspection use only. The others I use out in the shop but still with care.

    If you are going to be producing products for sale that need to be correct to millionths of an inch, that's another story...
    ​​​​​​
    Last edited by eKretz; 06-12-2022, 11:56 AM.

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    • #3
      Originally posted by eKretz View Post
      First off, what are you going to be using them for? If just in the home shop, just about anything you buy (as long as they're in good shape) will be plenty good enough for anything you're likely to be doing. Personally, I bought good condition used stuff. Got a few sets. Pratt & Whitney square blocks, and both Weber and Mitutoyo rectangular. The Mitutoyos are in the best shape, I keep those for inspection use only. The others I use out in the shop but still with care.

      If you are going to be producing products for sale that need to be correct to millionths of an inch, that's another story...
      ​​​​​​
      That answers my question perfectly, thank you!
      Len

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      • #4
        You're welcome!

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        • #5
          Don't be afraid of used sets,there are a lot of them out there for far less than they cost new.The thing about inspection and measuring tools is, they are usually taken care of, so many of them survive their owners and end up for sale.
          I just need one more tool,just one!

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          • #6
            And the further point that when it is out of cal for Boeing etc, it is perfectly fine for you in all likelihood.

            Those folks care about millionths. It is very likely that you would be very happy with 0.0001", and just about any set, used, import, etc, is going to be good to that.

            If you are very curious and fussy, you can internally qualify blocks. Usually, you can find multiple ways to get the same dimension with different combinations of blocks. That's the key.

            Set up two (or more) stacks that add to the same dimension. Compare them using your best measuring tool, micrometer, or an indicator on a granite flat, etc.

            Use the old engineering rule that "any two gauges (mics etc) that read the same on the same measurement, are probably correct". it is relatively improbable that two would have identical errors. If three read the same, you can generally be quite sure they are all 3 OK, on the same principle.

            So if both stacks measure the same, it is likely that all the blocks in each stack are within the tolerance that you can measure..... and so are at least good enough for you to use.

            No, it is not a guarantee. But it is pretty darn close to it for any shop which does not need traceability to national standards.
            Last edited by J Tiers; 06-12-2022, 12:55 PM.
            CNC machines only go through the motions

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            • #7
              Originally posted by Len View Post
              SO, can one expect decent results from imported gage blocks in, say, the sub $200 range?
              Many state they are in compliance with some sort of testing agency.
              Yes to your question..

              Agencies? We dont need no stinking agencies

              I have every manufacture of gauge block it seems. I have the dastardly evil import blocks also. Hey guess what? They all work the same.. Show me a person here that needs the variation between starrett or the all too offending import and Ill show you some swamp land I just acquired JR

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              • #8
                I'd bet that somewhere, there are bad sets of low cost import gage blocks. (Ali express, are your ears burning?)

                Mostly any sold by somewhat reputable sources are going to be good to the limits needed. Anyone who would not be satisfied with less than the best, already knows that and need not ask the question.
                CNC machines only go through the motions

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                • #9
                  Originally posted by J Tiers View Post
                  Use the old engineering rule that "any two gauges (mics etc) that read the same on the same measurement, are probably correct". it is relatively improbable that two would have identical errors. If three read the same, you can generally be quite sure they are all 3 OK, on the same principle.
                  Brings to mind the old polar navigators (before Satnav, GPS, etc.) protocol: Always have three chronometers. If you only have two, you're never sure which one is right. If you have three, the two which agree the most closely are likely near right.
                  Johnny

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                  • #10
                    Originally posted by wierdscience View Post
                    Don't be afraid of used sets,there are a lot of them out there for far less than they cost new.The thing about inspection and measuring tools is, they are usually taken care of, so many of them survive their owners and end up for sale.
                    The only issue of any substance I've found with purchasing used sets is sometimes they are not complete. If you can work around the few missing pieces then yes, they're the more affordable option.

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                    • #11
                      Many of you have seen this video I'm sure, but since it's on-topic I'll bring it up again for those who haven't. It's a very entertaining video on the origins of precision, with quite a bit of content on the development of "Jo-blocks".

                      https://www.youtube.com/watch?v=gNRn...achineThinking

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                      • #12
                        I bought a set of these for general home shop use and they are more than adequate:

                        https://www.ebay.com/itm/33071621339...UAAOSwerddCjfq

                        Ted

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                        • #13
                          Originally posted by Technical Ted View Post
                          I bought a set of these for general home shop use and they are more than adequate:

                          https://www.ebay.com/itm/33071621339...UAAOSwerddCjfq

                          Ted
                          Ha!
                          Joey Dong, he's my man!
                          If I ever decide to replace the pock marked grave marker I'm using for a surface plate I'll go for one of their AA's too.
                          It's all about attitude...if you think you're accurate it's close enough for me.
                          Len

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                          • #14
                            You would cry if you saw the sets we have at the museum, I had to scrape the rust off of one set, but in the real world, I could measure any three blocks together and they would be within 0.0001" of true which is more than good enough. Second hand sets are worth going for if complete.

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                            • #15
                              Originally posted by old mart View Post
                              You would cry if you saw the sets we have at the museum, I had to scrape the rust off of one set, but in the real world, I could measure any three blocks together and they would be within 0.0001" of true which is more than good enough. Second hand sets are worth going for if complete.
                              How did you check them?

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