Talk:Screw thread

Rolling vs Forming
Thread rolling is properly a type of forming -- not sheet metal rolling. The "Rolling" link should point towards this article: http://en.wikipedia.org/wiki/Cold_forming

I'd do it myself but I'm not sure how (I'm primarily a consumer of Wikipedia at the moment; keep up the good work folks). [unsigned, 2007-10-31]


 * This has just been fixed by another user. — ¾-10 02:51, 2 November 2007 (UTC)

Tinnerman nut?
Is there a name for that splitted punched hole in sheet metal that allows things to thread into it? — Omegatron 02:47, 21 December 2006 (UTC)


 * Tinnerman nut? Begs 02:56, 2 March 2007 (UTC)


 * I know that a nut stamped out of sheet metal with its hole thus formed, e.g. one that clips over the edge of a body panel, is called a speed nut in the automotive industry. Re the same type of hole in the middle of a sheet (not a nut): someone in some industry (autos? appliances?) must have a name for that. Haven't heard one if so. — ¾-10 02:45, 2 November 2007 (UTC)

Most common standard
The article Screw has a cited source saying that, as of 2006, UTS is still the most common standard, not Metric or BPS, yet this article says otherwise with no source. Apwvt 13:53, 21 March 2007 (UTC)


 * This has since been fixed. — ¾-10 02:47, 2 November 2007 (UTC)

Wireless LANs
Wireless LAN connectors are often "reversed". But that doesn't mean left hand thread. It means "reversed sex", i.e., pin inside the jack and socket inside the plug. At least that's all I've ever seen. Is there a reference for the "lefthanded" statement? Paul Koning 11:03, 13 September 2007 (UTC)

The wireless LAN connector, reverse SMA, is a right-handed thread. I've removed this. Robert Hiller 09:12, 30 September 2007 (UTC)

Tripod threads
There is confusion about standard tripod threads. Apparently this was originally 1/4-20 whitworth (55°), but a later standard (DIN 4503/ISO 1222) defined it to match 1/4-20 UNC (60°). This should be noted in the article along the with relative prevalence of the two. Robert Hiller 09:12, 30 September 2007 (UTC)

Precision threads
The article now mentions thread grinding for precision threads. What about lapping? That was used at least in the past -- Moore Special Tools did it as the final step after grinding for precision lead screws. Paul Koning (talk) 20:19, 18 April 2008 (UTC)
 * I think that grinding would be mergable into the first item ("cutting") in that list (as it is anohter method of simple removal excess material). --Splarka (rant) 07:32, 19 April 2008 (UTC)


 * It is true that grinding is a true metalcutting process, as each grain of abrasive functions as a microscopic single-point cutting edge (although of high negative rake angle), and shears a tiny chip that is analogous to what would conventionally be called a "cut" chip (turning, milling, drilling, tapping, etc.). However, among people who work in the machining fields, the term cutting is understood to refer to the macroscopic cutting operations, and grinding is mentally categorized as a "separate" process. This is why the terms are usually used in contradistinction in shop-floor practice, even though technically grinding is a subset of metalcutting. Therefore we could make "Thread grinding" a subhead below "Cutting", but if we do, we need to explain the above brief explanation.


 * As for lapping à la Moore Special Tool, I'm going to add it, with an explanation that it is basically ultra-deluxe toolroom practice, rarely employed except for, well, special tools (high-end machine tools). — ¾-10 14:53, 19 April 2008 (UTC)


 * Update: Done. — ¾-10 16:39, 19 April 2008 (UTC)

Right handed v Left handed
I thought the standard was called "right handed" because when the thumb of your right hand is pointed away from you, the fingers curl in a clockwise direction. The article says "This is known as a right-handed thread, since the natural screwing motion for a right-handed person is clockwise". I don't think either direction is more natural than the other. I've added a tag. Rojomoke (talk) 11:53, 14 November 2008 (UTC)


 * You're quite right. It's called "right-hand" because it follows the right-hand rule. (Well, in terms of nomenclature, "the" right-hand rule can be subdivided into various right-hand rules, including the right hand grip rule, but the point is still clear.) I changed it. — ¾-10 17:18, 15 November 2008 (UTC)

It is my understanding that determining thread handedness is the opposite of the rule given in the article: "To determine if a particular thread is right or left-handed, look straight at the thread. If the helix of the thread is moving up to the right, it is a right-handed thread and conversely up to the left, a left-handed thread. This holds whether the thread is oriented up or down."

In my use, when it is up to the left, it is right-handed, and when it is up to the right, it is left-handed. See: 


 * There's a little confusion because of lack of orientation. If the screw is held vertically then the text in the article is correct. I'll fix the text to note this. Wizard191 (talk) 17:50, 29 March 2011 (UTC)


 * I just thought we didn't need two different descriptions of handedness and tried to make the first as versitile as possible and removed the second. -AndrewDressel (talk) 18:27, 29 March 2011 (UTC)r


 * I noticed that you removed the second definition after I posted the above comment. It probably best that way. Wizard191 (talk) 22:10, 29 March 2011 (UTC)

The description regarding right handedness adds confusion to the reader. Better fixing this with an animation.

Dubious tag
Sorry about not putting a note here sooner (preferably before it was removed), but I added it because I don't know if a worm gear really counts as a "screw thread". I realize this is sort of cutting hairs, but, while a worm gear has a tooth that looks like a screw thread, it isn't really a screw thread. A different set of rules apply to gears than do screws. Screws are designed to mate with parts that have at least one full thread, whereas worm gears are not. Or maybe I'm just off base here. Wizard191 (talk) 21:14, 27 December 2008 (UTC)


 * I understand your logic but am dubious as to its validity. Yes, a worm gear fulfills a different role but I see no reason to believe that that difference disqualifies it from being a screw thread.  What about an Archimedes screw for instance? CrispMuncher (talk) 22:54, 27 December 2008 (UTC)


 * You are correct about Archimedes' screw, however it isn't listed as an application of a screw thread. This whole article addresses screw threads in the narrow sense of just "screws", which is why I don't think it should be included. Wizard191 (talk) 23:25, 27 December 2008 (UTC)

History of Screw threads
There seems to be not a word about the "ancient" history and development of screw threads. Given how modern life depends on them there should be, rather than the article being mainly a list of threadforms.--SilasW (talk) 13:49, 7 October 2009 (UTC)

I'll second that. EdX20 (talk) 18:24, 30 September 2012 (UTC)

I agree. I've been looking recently for some history on early thread forms and threaded fasteners. There's not much out there that I could find.--pegasis010 (talk) 12:36, 12 January 2013 (UTC)

Other examples of left handed threads
The flush handle of toilets in America. —Preceding unsigned comment added by 12.88.25.94 (talk) 18:16, 25 June 2010 (UTC)

Oval stick deodorant containers with an advance knob at the bottom have left-handed threads; they are made in huge quantities, as well. Some transit companies in past decades used screw-base lamp bulbs with left-handed threads to deter theft. (Sorry; I don't have a ref.) Regards, Nikevich (talk) 06:39, 30 September 2010 (UTC)

Reference
The following is a good ref for various thread standards: http://www.gewinde-normen.de/en/index.html Wizard191 (talk) 19:11, 29 June 2010 (UTC)

Bottle and jar cap thread standards
Some time ago, I investigated these, but don't have the reference any more. In the industry, they come under the heading of "finish". In addition to 1/4-turn wide caps, there are other multiple-start threads; I have seen a hex-start thread on a bottle of olive oil. Regards, Nikevich (talk) 06:44, 30 September 2010 (UTC)
 * Try &  Peter Horn User talk 19:13, 27 November 2010 (UTC)
 * As well as Plastic Bootle Corporation Available bottle closures Available jar closurres Put "bottle neck thread standards" and "jar neck thread standards" in the search engines. Peter Horn User talk 20:51, 27 November 2010 (UTC)
 * And Glass Thread DIN 40450 (Glasg) Peter Horn User talk 21:45, 7 December 2010 (UTC)

Tapered threads
What happened to the discussion of "tapered threads"? Are they mentioned elswhere? Tapered threads are the norm on pipes. Peter Horn User talk 01:22, 21 November 2010 (UTC)
 * Eureka! Threaded pipe Peter Horn User talk 02:02, 21 November 2010 (UTC)

Merge this article with Threaded Pipe article as suggested by merge template
I'm not sure I understand what is being suggested here. There is a proposal to merge the Threaded Pipe article with this one? That seems like a non-starter to me. Right now the Threaded Pipe article emphasizes tapered threads but pipes also use various kinds of compression fittings together with straight threads to make a seal. As such, it seems like the two articles only have a limited article.


 * Sorry about the long delay, but I was delayed by life from posting my explanation after adding the temps. I'm proposing just a section merge about tapered threads from threaded pipe, because there's nothing in this article about tapered threads; and as the other template here states, this article needs it. So I figured we could merge the section over and then add a main temp to the threaded pipe article. Wizard191 (talk) 01:05, 22 November 2010 (UTC)


 * Sounds sensible to me. In fact, I think it is the best path, as I have a bit of other (non-pipe) tapered-threads info that I could add here, from Smid 2008. — ¾-10 03:16, 22 November 2010 (UTC)

Labyrinth seal and tapered threads
The article contains this statement:
 * "... The seal provided by a threaded pipe joint depends upon the labyrinth seal created by the threads; upon a positive seal between the threads created by the deformation of the threads when they are tightened to the proper torque; and sometimes on the presence of a sealing coating, such as thread seal tape, or a liquid or paste pipe sealant such as pipe dope."

The Wikipedia article and another on-line source don't seem to support the idea that a tapered thread connection is an example of a labyrinth seal. The physical nature of the two seals is quite different and the applications are different. A labyrinth seal seems to be one that is used to make a seal around a shaft that rotates as part of its operation as opposed to a pipe thread connection which is fixed during normal operation.

Another minor objection to the statement is that saying "sometimes on the presence of a sealing coating,..." suggests that the use of a sealing coating is not the norm, where the actual situation is that it is used in the vast majority of all tapered thread connections. —Preceding unsigned comment added by Davefoc (talk • contribs)


 * I think you are right on both counts Dave. Wizard191 (talk) 14:59, 25 November 2010 (UTC)

Based on your comments Wizard191, I added a citation-required note to the labyrinth statement and changed the word "sometimes" to "normally" on the use of sealants with tapered threads. This doesn't go to the general problem of the paragraph that there aren't any citations and it might not have been the best fix for the sentence. I think it would be reasonable to just remove the labyrinth thread comment after a few days. It seems very likely at this point that it is just wrong.

Broom stick / mop stick threads
I have come accross two different threads at the ends of broom sticks (one of each). One appears to be an "M"22 x 4 or pehaps a $7/8$ in - 6 tpi (mould in plastic), as near as I am able to tell using a vernier and a thread gauge. It's hard to tell. The other appears to be an "M"20 x 5 (cut in wood), as near as I am able to tell using a vernier and a thread gauge. Peter Horn User talk 18:57, 27 November 2010 (UTC)

Thanks Lambiam
For this high-power edit. Awesome. — ¾-10 01:35, 13 January 2011 (UTC)

Royal Microscopical Society thread
Royal Microscopical Society threads are mentioned twice in the "Other current standards" section. Would someone knowledgeable like to choose which is the best and delete the other, or combine the information ? Darkman101 (talk) 14:38, 9 February 2011 (UTC)


 * Thanks for the note, I combined the two. Wizard191 (talk) 16:00, 9 February 2011 (UTC)

BSP is listed twice
Brtish Standard Pipe is listed both as a metric thread, and as an "other standard" — Preceding unsigned comment added by 203.206.162.148 (talk) 06:03, 30 September 2014 (UTC)

The 1947 ISO Standardisation
More information is needed on the standardisation that ISO did in 1947. For example, there were separate French, German, and Japanese screw threads of the common designations, and the Swiss had a set for the tiny screws used in watchmaking. 74.94.150.197 (talk) 16:53, 29 July 2015 (UTC)