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When did the change take place?

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  • When did the change take place?

    Today I bought an elderly Tap and Die set . On cleaning and checking it I found that it contained taps and dies labelled 3/16 th by 24, and others labelled 10 by 24. They all appeared to be original to the set, unfortunately the label in the wood lid is unreadable, the larger tap handle is engraved or stamped Butterfield, Derby Line, Rock Island Quebec. I am left wondering what are the differences, if any between the threads and when the set was originally sold. All the taps and dies and holders seem usuable, I reckon I got my money.s worth( 46$) Regards David Powell.

  • #2
    It’s a question I would like to know the answer to as well.

    Boats

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    • #3
      Screw eyes and turnbuckles come in 3/16 - 24.
      When I get Time... I'll...

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      • #4
        They are very close, but not the same
        3/16" is .1875"
        and # 10 is .060" + 10 x.013" which is .190"
        The "number system " is based on .013" increments with .060" as the starting point.
        You see a 4-40 for example as " .060 + 4 x .013"= /112" and 5-40 is .125 ( .060 + 5 x .013")
        During the 1930's industry started switching over from fractions to numbers for small threads. and at the end of WW II
        almost all industrial operations had changed over to numbers .. except for repair work

        Rich

        Edit - In 1952 ANSI made major changes to thread systems and screw construction, like Bolt Head & Nut sizes and Allen ( socket Head) wrench sizes
        Last edited by Rich Carlstedt; 05-12-2021, 10:56 PM.
        Green Bay, WI

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        • #5
          This kind of change in never overnight. I can recall seeing 3/16" bolts and nuts in hardware stores in the 50s.
          Paul A.
          SE Texas

          And if you look REAL close at an analog signal,
          You will find that it has discrete steps.

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          • #6
            The other guys beat me to it, but I was going to say at some point in the 1930's. I love tap sets like that, and have collected a few. As for what changed, in the USA one Henry Ford was bedeviled in his efforts to organize tooling for his car factories, so he began a campaign to specify all Imperial dimensions in decimal units instead of the then-common fractions. Machine screw sizes were standardized into a numbered system, since there were several "competing" systems -- I think they tried to harmonize all the "nearest" sizes. What they ended up with was largely based on common practice at the time, which in turn came from the market share of the largest companies. Smaller and more "specialized" tap sizes didn't make it into the standards (such as gun screws, clock screws, sewing machines, telephone equipment screws, etc). eBay is a rich source of vintage specialized threads.
            25 miles north of Buffalo NY, USA

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            • #7
              That explains it very well, thanks. After reading then reply’s went to Google & found this.

              https://www.rustmag.com/gear/2018/1/...thread-systems

              Boats
              Last edited by boats; 05-13-2021, 06:25 AM.

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              • #8
                Originally posted by Rich Carlstedt View Post
                They are very close, but not the same
                3/16" is .1875"
                and # 10 is .060" + 10 x.013" which is .190"
                The "number system " is based on .013" increments with .060" as the starting point.
                You see a 4-40 for example as " .060 + 4 x .013"= /112" and 5-40 is .125 ( .060 + 5 x .013")
                During the 1930's industry started switching over from fractions to numbers for small threads. and at the end of WW II
                almost all industrial operations had changed over to numbers .. except for repair work

                Rich

                Edit - In 1952 ANSI made major changes to thread systems and screw construction, like Bolt Head & Nut sizes and Allen ( socket Head) wrench sizes
                Rich, thank you for a very informative post!

                metalmagpie

                Comment


                • #9
                  For what it's worth, I buy 3/16" nuts & bolts from local hardware & fastener supplier stores today, in 2021, and use them interchangeably with 10-24's and with 10-24 holes that I tap. I realize that this does not answer when a 3/16 tap became a 10-24 tap, etc, etc, but it appears that the tolerances of the garden variety ones anyway, are loose enough that it doesn't matter. Or maybe what they call "3/16" are really #10? I suppose I could go measure some...
                  "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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