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  • Question Re threading

    Does anybody have a link to a website that shows the basics of cutting threads. Like what the numbers mean and how to cut them.

    I am not looking to do this myself, but just want to understand it. The numbers I see are 3/8-10
    5/16-14
    5/16-18
    3/8-11
    3/8-11.5

    as far as I can tell, the 3/8 is rod size and 10 is the turns per inch maybe?

  • #2
    of the sizes that you state in your post the only standard that i recognize is 5/16-18.
    im not familiar with the others but they could be pipe threads...jim
    ...jim

    Comment


    • #3
      Perhaps the best source of information, if you really want to understand screw threads, is "Machinery's Handbook." It will tell you more than you ever wanted to know. For this purpose, an older edition will be every bit as good as the latest up-to-date, except perhaps for metric.

      As far as cutting threads, South Bend's "How to Run a Lathe" book explains it pretty well.

      You have the basic idea, although I assume you just made up a lot of those examples randomly. As jim points out, the only recognizable standard thread I see is 5/16-18.

      In the US, there's a standard "National Coarse" series and a "National Fine" series of threads. The coarse threads are ones like 1/4-20, 5/16-18, 3/8-16, 7/16-14, 1/2-13, etc. and the fine threads are 1/4-28, 5/16-24, 3/8-24, 7/16-18, 1/2-20, etc. (I did those from memory, so the 7/16" values may be wrong, but it's something like that.) There is also "National Extra Fine" and "National Special" that are used infrequently, but exist. For instance, there's a 5/16-32 NEF.




      [This message has been edited by SGW (edited 12-31-2004).]
      ----------
      Try to make a living, not a killing. -- Utah Phillips
      Don't believe everything you know. -- Bumper sticker
      Everybody is ignorant, only on different subjects. -- Will Rogers
      There are lots of people who mistake their imagination for their memory. - Josh Billings
      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
      Don't own anything you have to feed or paint. - Hood River Blackie

      Comment


      • #4
        cuemaker --

        Your speculation is exactly correct: the standard notation system to identify inch-dimensioned screwthreads is to state the Major Diameter (what you called the "rod size") followed by a hyphen, and the the Number of Threads per Inch (you said "turns per inch", which is probably more correct in terms of English-language linguistics).

        A bit more information is needed to fully identify the screwthread . . . the "form", which could be the obsolescent US Standard (aka American National), British Standard (aka Whitworth), or the current Unified threadform . . . or even less-common forms such as Square, Acme, Buttress, Sharp-V, and on and on.

        As SGW mentions, there are standard pairings of Major Diameter and Number of Threads per Inch -- usually in two Series, Coarse and Fine.

        In the US the Coarse and Fine screwthread series were called just that, Coarse and Fine. The English took a different route, calling their Coarse series "British Standard Whitworth" and their Fine series "British Standard Fine".

        Putting it all together, the screwthread on a 1/2 inch diameter bolt or capscrew in the Coarse-thread Series would be fully identified in the following ways:

        "1/2 - 13 NC" if the threadform is US Standard,

        "1/2 - 13 UNC" if the threadform is Unified (note that the "UN" means "Unified", NOT "Unified National")

        "1/2 - 12 BSW" if the threadform is British Standard Whitworth.

        I'll note here that ISO Metric screwthreads are identified using a similar but distinctly different notation system. In the ISO Metric system, the first character is "M", followed by the Major Diameter in millimeters, a hyphen or "x", and the Pitch (the distance between successive threads measured along the axis of the screw) in millimeters. A typical ISO Metric screwthread would be "M 8 x 1.25" or "M 8 - 1.25".

        The ISO Metric screwthread standards do include both a Coarse and Fine Series, but the Series is not included in the standard notation.

        Finally, I'll mention that many non-standard combinations of Major Diameter and Number of Threads per Inch are in use, for a number of different reasons.

        John

        Comment


        • #5
          Try this website.

          http://www.efunda.com/designstandard...rews_intro.cfm
          Ed Pacenka

          Comment


          • #6
            Great info! Thanks everyone. I am working on getting 2 books, the general machinery one and The Amateurs lathe book.

            As far the examples I gave, all those are used or have been used in cue joints.

            The thing that started my thread was a set of taps for the threads that i mentioned seemed expensive. It was from a billiard supply company the provides cue making stuff. And the pre made joint pins also seem expensive.

            I figuered it would be easier to buy them than make them, but I still want the knowledge.

            Comment


            • #7
              well that clears everything up. i would have a hard time designing anything while at a pool hall.
              the real reason those are that way is its propritey belonging to the cue manufacturer. that way if any thing goes bad you have to send it back to them,or so they think but little do they realize that we can make anything they can and better.
              up for a game of rotation?...jim
              ...jim

              Comment


              • #8
                Check the MSC catalog www.mscdirect.com and look in their "Special taps" section. They have quite a selection of oddball threads available. If any of the ones you need are there, it's just about guaranteed they'll be cheaper than a billiard supply house.

                Of course, there is the possible problem of thread form. The MSC specials are 60 degree included angle threads, and the weird and wonderful "billiard specials" may be something else unknown to anybody.

                If I wuz making cues and making the joint fittings, I'd use something like 3/8-16. Except for slightly faster assembly/disassembly, I see no reason to use something like 3/8-10, or the others.




                [This message has been edited by SGW (edited 12-31-2004).]
                ----------
                Try to make a living, not a killing. -- Utah Phillips
                Don't believe everything you know. -- Bumper sticker
                Everybody is ignorant, only on different subjects. -- Will Rogers
                There are lots of people who mistake their imagination for their memory. - Josh Billings
                Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                Don't own anything you have to feed or paint. - Hood River Blackie

                Comment


                • #9
                  Rotation?? Sure. Little something on the 9 and 15??

                  Or where you just thinking of just playing to the 9?

                  Comment

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