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Okay - when did 1" UNF threads change???

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  • Okay - when did 1" UNF threads change???

    I look on all the charts and they all list 1 inch fine threads as 1"-12. So, is ask the boss to get me a couple 1"12 x 4" inch bolts for a project I am finishing and everyone tells us that the thread is 1"-14... So, Just when exactly did this change? and what other changes to the standard have happened?

    I even have the 1"12 tap....

  • #2
    https://en.wikipedia.org/wiki/Unified_Thread_Standard

    "(*) For many years non-standard 1-inch 14-tpi nuts and bolts have been widely used instead of standard-sized 1-inch 12-tpi fasteners; consequently 1″-14 fasteners are easier to find and less expensive than 1″-12 fasteners. After several decades 1″-14 fasteners have now come to be commonly referred to as "Standard Fine Thread" or "UNF". Though technically incorrect (the UNF standard specifies 1″-12), size 1″-14 is universally accepted as standard for fine-threaded 1-inch fasteners, and "1-inch 14-tpi NF" has become established as a "common use" term, or "a genericized brand name/standard". In other words, the 1″-12 standard has lacked effective enforcement for a long enough time (many decades) to give generic trademark–like status to 1-inch 14-tpi fasteners."

    So it's the standard unstandard

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    • #3
      Originally posted by MattiJ View Post
      https://en.wikipedia.org/wiki/Unified_Thread_Standard

      "(*) For many years non-standard 1-inch 14-tpi nuts and bolts have been widely used instead of standard-sized 1-inch 12-tpi fasteners; consequently 1″-14 fasteners are easier to find and less expensive than 1″-12 fasteners. After several decades 1″-14 fasteners have now come to be commonly referred to as "Standard Fine Thread" or "UNF". Though technically incorrect (the UNF standard specifies 1″-12), size 1″-14 is universally accepted as standard for fine-threaded 1-inch fasteners, and "1-inch 14-tpi NF" has become established as a "common use" term, or "a genericized brand name/standard". In other words, the 1″-12 standard has lacked effective enforcement for a long enough time (many decades) to give generic trademark–like status to 1-inch 14-tpi fasteners."

      So it's the standard unstandard
      Timely, was just yesterday working with a 1" 14 and wondering the same thing
      .

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      • #4
        I know what they're doing. They're trying to get us use to finer threads so they can slip-in a metric without us knowing.

        I cut my first M10 x 1.0 the other day.

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        • #5
          Now you get to make your own bolts, first make studs, then weld or loctite nut on one end.

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          • #6
            This on bite me in the butt a while back customer gave me a print with a 1" Fine hole he didn't list the TPI on the print. So I look on the thread chart and it lists 1" 12 as fine so I get the hole taped. He comes by with the bolts for the project and they don't fit there 1"14. luckley I only did the one of 4 of the parts as we only had the metal to do one at that time. 1" 12 is crossed off all my thread charts you can't find 1" 12 bolts in Portland OR. Wwe were going to make all the parts 1"12 but after a few phone calls we scraped the part. Ken

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            • #7
              My UNF thread chart lists 1" and everything above as having 12 tpi. At least up to 3" diameter.

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              • #8
                I've never had this come up but I just looked at some of my references. My Starrett wall chart (1999) and my South Bend Lathe wall chart (picked up at IMTS in 1994) show 1"-14 as standard. The South Bend wall chart further shows the 1"-12 as "Special". My _Starrett Book for Student Machinists_, 16 ed., rev. (1975) and my _Machinery's Handbook_ 21st ed., 1979 both list 1"-12 as standard.

                Egad screw threads are fascinating!

                David

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                • #9
                  I just checked on the Mc Master web site. In hex head bolts, they only have 1"-14 NF , but they have both 1"-12 and 1"-14 taps. Go figure!
                  Craig

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                  • #10
                    Originally posted by ckalley View Post
                    I just checked on the Mc Master web site. In hex head bolts, they only have 1"-14 NF , but they have both 1"-12 and 1"-14 taps. Go figure!
                    Craig
                    But nuts are available widely in many variations (grade 5/grade8/nyloc/stainless/another stainless/extreme) also in 12 TPI !

                    No bolts of any kind but plenty of nuts. Thats NUTS!

                    Doesn't make sense (no supprise here, I have given up on threaded parts)

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                    • #11
                      Originally posted by ckalley View Post
                      I just checked on the Mc Master web site. In hex head bolts, they only have 1"-14 NF , but they have both 1"-12 and 1"-14 taps. Go figure!
                      Craig
                      however,socket head 1 inch in 12&14 threads

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                      • #12
                        FWIW, my ancient Patience and Nicholson wall chart lists 1x12 under UNF and 1x14 under UNS (Unified Special, a "standard" about which there seems to be a good deal of misinformation on the Internet). The preferred drill sizes are 59/64" and 15/16" respectively. Curiously, the British Standard Fine thread is coarser than either, at only 10 TPI.

                        CCWKen, alas, you're in no danger of a metric infiltration—for some reason I cannot guess, standard metric threads go from 24mm direct to 27. As 1"=25.4mm, there's no close metric thread equivalent for bolts, though there is a standard metric conduit thread of 25x1.5.
                        Last edited by Mike Burch; 05-15-2018, 08:44 PM.

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                        • #13
                          Originally posted by kf2qd View Post
                          ....................... the thread is 1"-14... So, Just when exactly did this change? p....
                          I can tell you that I started with a Die company in 1985 and the company had switched over "then" to 1"-14, but the old prints showed 1"-12

                          So I would guess between 1973 and 1985

                          Rich

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                          • #14
                            Originally posted by ken View Post
                            This on bite me in the butt a while back customer gave me a print with a 1" Fine hole he didn't list the TPI on the print. So I look on the thread chart and it lists 1" 12 as fine so I get the hole taped. He comes by with the bolts for the project and they don't fit there 1"14. luckley I only did the one of 4 of the parts as we only had the metal to do one at that time. 1" 12 is crossed off all my thread charts you can't find 1" 12 bolts in Portland OR. Wwe were going to make all the parts 1"12 but after a few phone calls we scraped the part. Ken
                            Just curious but who paid for the scrapped part? The customer, because he failed to specify the thread fully, or you, because you didn't know that whatever the standard says, accepted custom and practice is 14TPI?
                            'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

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                            • #15
                              Make them initial the drawing.

                              Originally posted by ken View Post
                              This on bite me in the butt a while back customer gave me a print with a 1" Fine hole he didn't list the TPI on the print. So I look on the thread chart and it lists 1" 12 as fine so I get the hole taped. He comes by with the bolts for the project and they don't fit there 1"14. luckley I only did the one of 4 of the parts as we only had the metal to do one at that time. 1" 12 is crossed off all my thread charts you can't find 1" 12 bolts in Portland OR. Wwe were going to make all the parts 1"12 but after a few phone calls we scraped the part. Ken
                              There is some kind of stupid rule somewere, written by an idiot,concerning metric thread pitch.So when the "' blue print drawer",says m10 thread,YOU are automatically supposed to know what pitch tap to use.So you have a $5000 part and the "DESIGNER",Doesn't put the pitch on the thread. The customer or the foreman or the estemater,might get upset if you want to clarify the thread pitch.But if you tap the wrong thread they will all point the finger at YOU.Edwin Dirnbeck

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