Talk:Screw/Archive 4

Staining wood
If the reason for staining wood is rust, then stainless steel would work the same. It is not the reason for using brass.

" If the reason for staining wood is rust stainless steel would work the same as brass in dry environments in most timber but in damp conditions the screw surface in the wood could become sufficiently anaerobic for the steel to corrode enough for the wood to become stained by the iron compounds released. In acidic timber, such as oak, the grades of stainless steel commonly used for screws can produce staining even in nominally dry conditions, if any moisture at all can get into the wood. Brass does not usually stain acidic woods in damp conditions but would corrode in wet conditions, also staining the wood (but green/blue, rather than brown/black) and in such conditions small gauge brass screws may suffer sufficient corrosion as to fail through dezincification."PJWoodbridge (talk) 09:56, 17 September 2018 (UTC)

Reasons for using brass would be aesthetic, perhaps avoiding interference or reception of electromagnetic radiation. — Preceding unsigned comment added by 31.210.187.89 (talk) 19:36, 17 November 2012 (UTC)

Reasons for using brass would often be aesthetic, should always be used for fixing brass fittings, to avoid the risk of electrolytic corrosion from mixing metals, but sometimes for avoiding risk of magnetism (for example in proximity of a compass), as stainless steel screws are not always made of non-magnetic grades.". [ omit reference to electromagnetic radiation and interference as brass is perfectly capable of receiving electromagnetic radiation because it is a quite good conductor of electricity] PJWoodbridge (talk) 09:56, 17 September 2018 (UTC)


 * reasons to use brass hardware include not sparking when struck with a steel tool. required in explosive environments. In some cases non-ferrous tools are used for the same benefit. Ken (talk) 16:53, 28 March 2013 (UTC)

History Section for "Screw" miscarries source info from cited wiki entry "Screw Press"
The History section for "screw" writes that the "screw press" (hyperlinked to wiki entry for screw press ) was used as early as the 1st century BC in the Mediterranean. The hyperlinked wiki entry for screw press, however, cites a source claiming the earliest use in Roman culture as the first century AD. One of these has to be incorrect. I am wondering if the entry for "screw" was simply flipped up in carrying it over from the "screwpress" source? Thanks for all you do, wiki people! -James T. — Preceding unsigned comment added by Jtexconsult (talk • contribs) 02:59, 15 December 2015 (UTC)

Where to place info on gauge diameter?
I found this technical info on the equivalent mm diameter of various gauge sizes for self-tapping screws and wanted to add it to this article, but I'm not sure where to place it:

Source:

There is also more valuable info on this site, such as
 * 1) Metric-Imperial conversion table → could go to "ISO metric screw thread"
 * 2) Metric Thread Pitch and Tapping Drill Table → could go to "ISO metric screw thread"
 * 3) Imperial thread pitch table → could go to "Unified Thread Standard"

Let me know what you think. invenio t c 12:23, 1 June 2010 (UTC)


 * We already have all that info in the following articles: Unified Thread Standard, List of decimal-fraction equivalents: 0 to 1 by 64ths, and ISO metric screw thread. Wizard191 (talk) 15:41, 1 June 2010 (UTC)
 * Deleting List of decimal-fraction equivalents: 0 to 1 by 64ths, and ISO metric screw thread was not helpful. Peter Horn User talk 04:53, 4 April 2019 (UTC)

Type tip
add type tip, is important some references

https://www.aallamericanfasteners.com/documents/pages/Screw%20Thread%20Points%20-%20FBB.pdf — Preceding unsigned comment added by 186.31.255.93 (talk) 22:51, 21 December 2018 (UTC) https://www.instockfasteners.com/TOOLS/screwpoints.ASP — Preceding unsigned comment added by 186.31.255.93 (talk) 22:47, 21 December 2018 (UTC)
 * The first link refuses to open. Peter Horn User talk 00:06, 16 May 2019 (UTC)

Japanese grades of metric bolts and screws
I have long since noticed that upon looking at the bolt heads in some Japanese cars that the Japanese have their own grade system for metric bolts. They are single digit. Can someone give details? Peter Horn User talk 13:51, 25 October 2018 (UTC)
 * Screw Could a Wikipedian with a Japanese background provide info about the Japanese grading system? Peter Horn User talk 02:07, 28 March 2019 (UTC)
 * Honda is one of those cars. Peter Horn User talk 04:58, 4 April 2019 (UTC)
 * See Head markings and properties for metric hex-head cap screws. Who can provide the JIS equivalents? Peter Horn User talk 02:46, 18 April 2019 (UTC)

Any one? I'm also looking for a copy of the now obsolete JS metric thread standard which had M5x0.9 instead of the DIN M5x0.8 etc etc Peter Horn User talk 00:25, 16 May 2019 (UTC)

Peter Horn User talk 13:33, 18 April 2019 (UTC)

, From what I can glean, common markings might be 4T, 7T and 9T. The number indicates the minimum tensile x 100 in N/mm2. The relevant standard looks like JIS B 1180. It should be available in English translation but I couldn't find a free version on the net. I did find JIS B1186: Sets of high strength hexagon bolt, hexagon nut and plain washers for friction grip joints. Please see p 5 and p 15 (section 14.1). These particular bolts would be marked: F8T, F10T or F11T. This is the best I could do. Regards, Cinderella157 (talk) 01:50, 16 May 2019 (UTC)
 * . Thanks for the info and the additional bolt head markings. However I was referring specifically to the head markings that I have actually seen on heads of the bolts on Honda cars, doors and door mountings not to mention the engines, and the heads of the bolts on Honda engine-generators. The head marking on all of these is a simple 7, nothing more. If you have a friend or acquaintance who happens to own any of these, have a look. Or if you happen to walk by a small construction site and see a Honda engine-generator, have a look. The M5x0.9, etc, is of historical interest to restorators because it is apt to be found on motorcycles, etc, that were built before ISO metric threads were adopted. Peter Horn User talk 13:58, 16 May 2019 (UTC)
 * Firefox is causing me a headache, perhaps I'll have to replace it with Google.. Quote:"Your connection is not secure. The owner of itc.co.ir has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website."unquote. Can you download the page(s) and send them to me as an Email attachment at peter.j.c.horn@hmail.com ? Thanks. Peter Horn User talk 14:23, 16 May 2019 (UTC)

History (2010 discussion thread)
If the screw was described by Archytas of Tarentum (428 – 350 BC), it cannot have been invented by Archimedes (c. 287 BC – c. 212 BC). Engelsman (talk) 18:16, 14 October 2010 (UTC)


 * Archimedes' screw was a water lifting device (water pump not reliant on pressure), not a screw in the sense of a fastener. Both use an inclined plane wrapped around a lever, but to different ends: mechanical attachment vs. gravity assist. — Preceding unsigned comment added by 69.221.213.5 (talk) 12:52, 27 June 2019 (UTC)


 * I marked the two sentences with dubious tags. Wizard191 (talk) 15:53, 31 December 2010 (UTC)


 * The 15th century is in Rybczynski. David R. Ingham (talk) 06:02, 15 March 2012 (UTC)

Need a simpler distinction between screw and bolt
I tried to add a sentence that would give a simpler distinction between screw and bolt but it was reverted. There needs to be something in there that answers the question for 95% of the readers who don't care about the intricacies of the definitions. I inserted, <>

The reverting editor said that the point of that section is that there is no universally accepted distinction between the two. I disagree. The point of that section is to try to give an idea of what that distinction is. Most readers do not want to wade through a very technical and hard to understand text. They just want their question answered in a general way.Star-lists (talk) 22:26, 30 May 2015 (UTC)


 * This isn't an uncommon situation on WP. The usual fix is along the lines of
 * There is no universally accepted distinction between a bolt and a screw. Arkwright's Dictionary of Spanners gives the difference as bolts being aligned north-south, screws east-west. This is often stated as the mnemonic, "Screws follow the Sun, a bolt is what fastens a polar bear's nuts." A different definition, more common in the US than in Europe, is given in Bubba's Bolt-o-rama that bolts are made of steel, screws of rubber.
 * Andy Dingley (talk) 19:20, 31 May 2015 (UTC)


 * User:Star-lists, you've got a good-faith point, and I just redressed the concern by adding back the core of your point although without including any inaccuracy. Andy's spiel is (purposely) inaccurate and snide. Star-lists, you're totally right that "They just want their question answered in a general way." But the only simple AND accurate answer to the question is that bolts tend to take nuts whereas screws tend not to (they tend to thread directly into a substrate). But you have to duly note the "tend" part, because the obvious exceptions follow. Consider machine screws, such as a pan-head 10-24. It's not unusual for them to take nuts, that is, to be used just like a "little bolt". Now consider what American car mechanics, if not others, usually call cylinder head bolts, not cylinder head screws. They don't take nuts, they screw directly into the block. And consider what many people call lag bolts. They're really lag screws, but that's English as she is spoke. Those are the common examples of why most people's version of "a simple distinction" is inaccurate. By the way, this article was developed when it was, knowingly, one article covering all screws and bolts (since, as just illustrated, you can't talk about them entirely mutually exclusively anyway). That's why it was perfectly fine to have pictures of bolts here. The later WP:content forking of creating a separate bolt (fastener) article was pretty evidently a disingenuous episode of someone deciding to change that decision without consensus and waiting to see whether anyone noticed. Good thing it doesn't matter enough to bother spending the time deforking. Andy thinks his forked article is so much better, but gee, if you read it you find out it re-expresses the same answer as this one does (in so many words, usually but not always, "degree of overlap", "can be either", etc). But you know, there's an overblown/inaccurate "fairly good"-versus-"crap" distinction made (see the talk page there), because it feeds an ego. — ¾-10 23:27, 1 June 2015 (UTC)
 * ANI is worthless or you'd be there already but any more of this " Andy's spiel is (purposely) inaccurate and snide. " crap from you and I'll give it a go anyway. Andy Dingley (talk) 00:25, 2 June 2015 (UTC)


 * It should be possible to include "rules of thumb" helpful to most readers, while making it clear they only tend to be the case... not a 100% accurate distinction. I think "has a nut" isn't as good a rule as "is intended to fasten things together" compared with "screw into material". Also, if you go to a hardware shop and buy a packet of screws you shouldn't be surprised they don't come supplied with nuts... and that is a pretty good, simple, real-world illustration of the difference Maitchy (talk) 02:05, 9 February 2016 (UTC)


 * Who really cares if it's called a screw or a bolt (past a point)? This article seems to be bogged down in pedantry. Kortoso (talk) 23:11, 29 June 2016 (UTC)

I agree on the comment regarding pedantry. I may be over-simplifying matters, but despite some conventional names which exist, a screw and bolt should be easily differentiated as such: "With exception of the head: A bolt is cylindrical in its entirety. The thread diameter is a constant value.

A screw is either conical in its entirety or contains a conical section at the end most distal from the head. In this conical region, the threads are helical in form. The thread diameter is not a constant."

This is how I visually distinguish the two when verbally identifying them. This doesn't always agree with conventional terms, but that's when I find people are unable to draw a fundamental and universal distinction between the two. The rabbit hole is - Why? (talk) 04:20, 2 September 2017 (UTC)


 * The section of the section on the distinction reads like someone's original research, trying to interpret the American legal definition and then reconcile it with the vagaries of actual usage. It's also at odds with British usage where, nine times out of ten, a BOLT usually has a smooth shank between thread and head and normally of the nominal fixing diameter slightly larger than the thread, whereas a SCREW is usually threaded almost up to the head. Exceptions - wood screws that may have an unthreaded section, but usually smaller than the thread diameter. Note that this definition distinguishes a coach bolt (nutted, with full diameter plain shank and square under the head) and a coach screw (normally used into wood, with a narrower shank and no square section). Stub Mandrel (talk) 20:50, 25 April 2018 (UTC)

To which I would add that a coach bolt is indeed nutted with plain shank and anti-rotation square under head, and the very different coach screw does go into wood, bot it has a tapered section at the point, with much of the length parallel threaded, maybe some unthreaded shank near the head and usually a square head to allow a decent amount of torque to be applied. Nowadays, maybe Torx head. Generally an over-large woodscrew which you would not be able to insert easily with a screwdriver. The coach bolt can only be used with a nut, the coach screw is self threading in wood or maybe some plastics (probably in a drilled hole unless you are very strong) and can't use a nut. A coach bolt could be used for things like fixing the locking bolt or hasp for a padlock to the outside of a door, nut and washer on the inside, which then can't be unscrewed from outside. A coach screw simply joins two pieces of wood, often at right angles in a T joint. I have used both of these in those ways recently.

Unfortunate choice of similar names for different things. — Preceding unsigned comment added by Tiger99 (talk • contribs) 13:56, 9 March 2020 (UTC)

Distinction between bolt and screw
I think this has become somewhat confused due, not to stupidity by anyone, but rather differing language and terminology on each side of the Atlantic. If I order a bolt in the UK it will come with a length of plain, unthreaded shank, every time. If I order a screw or machine screw it will come fully threaded, every time. Also, machine screws come in far larger diameters than the article currently suggests, and may have either hex, cap or Torx heads, not usually Philips or Pozi. Worse, a set screw may in fact be just an ordinary (machine) screw, and not headless, to be used as a grub screw. All this is regardless of what the various standards say. Considering that probably 99% of end users do not have access to the likes of ISO standards due to their cost, it is hardly surprising! In any case it seems that the terminology was in use long before ISO existed. Considering that BSI probably preceded every other standards body, early versions may be instructive. Sadly as I am retired I no longer have access to the standards library at work so can't look them up to see how things were once named. Most of my experience is with fastenings of either 8.8 grade or the similar old BS grade S or higher, i.e. high tensile, so I don't know much about the naming conventions for the mild steel varieties commonly available in DIY stores, except to note that all I have seen were fully threaded and in common usage should be screws.

I have only made one small edit, to note that a set screw is often known as a grub screw. That is fairly clear and distinct, and adds no confusion. It also agrees with the set screw article. I am not going to touch the main body of the article for fear of damaging a lot of good work that has been done my many people, and I don't see a clear way of fixing things that will not offend many. Changes would be needed in nearly every section. We would also need to take into account common usage other than in the UK, although we should be aware that standardised threads, a key requirement to allow mechanical engineering to fully develop, were first introduced in the UK by Josiah Whitworth a long time ago, and strictly speaking, whatever terminology he used should have been retained. I suspect that everyone has drifted well away from that in different directions. Anyway, it is not about being nationalistic, just hoping to get some form of consensus that will be fully understood by as many bolt users as possible, everywhere. We are not there yet.

Please discuss freely, and if I am wrong, say so.

Tiger99 (talk) 13:36, 9 March 2020 (UTC)


 * Any generic product that exists for a long enough time will develop confounding terminology, the problem for Wikipedia is that the guy at the fastener shop mostly understands what you are asking for, so they never see the need to try and more precisely define things. To me a bolt can have a fully threaded shank, screws are pointed and are used in soft materials or for sheet metal, machine screws are under 5/16" are always fully threaded.


 * I have also heard bolts fasten to nuts and screws fasten to threaded objects, to me it seems ridiculous to change the name of an object based on it's intended use when the applications are so similar and the object is unchanged.


 * Creating an article that addresses all this seems like a very large challenge, I suspect you would find many conflicting sources. Toasted Meter (talk) 16:56, 9 March 2020 (UTC)


 * "If I order a bolt in the UK it will come with a length of plain, unthreaded shank, every time."
 * Not always.  It's just not consistent.
 * Also note that many suppliers sell "set screws", but they use this for fully-threaded hex bolts, with full size heads.  When 'set screw' (as you seem to be using it above) has a long history as a screw with a reduced size head, for use as a clamp screw in shaft collars with limited clearance to the sides.
 * Also see bolt (fastener). Andy Dingley (talk) 17:05, 9 March 2020 (UTC)

Lag Screw
https://www.youtube.com/watch?v=M99gtHeCBb4 says their Lag screws were hammered in until the last few turns. Can anyone confirm? Wizzy&hellip; &#9742; 16:58, 27 April 2020 (UTC)


 * It might make sense if you don't have powered fastening tools, it would take a long time to drive it by hand. Toasted Meter (talk) 19:54, 27 April 2020 (UTC)
 * As a quick and simple way to install a crossbar high on a pole where it's mostly loaded in shear and not subject to significant withdrawal force, it's fine. The proper way is to pre-drill an appropriate hole and to turn it with a wrench. Hammering reduces the gripping power all but the last few threads. One might use a hammer to seat the lag in the hole, but no engineer would endorse hammering one most of the way in if it's a critical application. In this case, up in the air with limited scope for leverage, quick and simple wins.  Acroterion   (talk)   01:11, 28 April 2020 (UTC)

Conflicting metric terminology
Here, in the Screw section it says: "If the thread does not use the normal coarse pitch (e.g. 1.25 mm in the case of M8), then the pitch in millimeters is also appended with a multiplication sign (e.g. "M8×1" if the screw thread has an outer diameter of 8 mm and advances by 1 mm per 360° rotation)."

However in the article ISO metric screw thread it says "A metric ISO screw thread is designated by the letter M followed by the value of the nominal diameter D (the maximum thread diameter) and the pitch P, both expressed in millimetres and separated by the hyphen sign, - (e.g., M8-1.25). If the pitch is the normally used "coarse" pitch listed in ISO 261 or ISO 262, it can be omitted (e.g., M8). [...] A common error or colloquialism is to use the 'x' or '/' when describing the pitch, so "M8x1.0" or "M8/1" might be seen where "M8-1.0" would be the clearer text to use. Similarly a 30mm bolt with this pitch might be written as "M8x1x30", where "M8-1.0x30 could be used." (Hmm. Also there really is a missing quote in that article.)

Clearly one of those is wrong (I would assume this one, and that hyphen is the correct way.) 82.24.247.127 (talk) 11:22, 20 May 2021 (UTC)


 * Neither is common and both are lacking references that could serve to verify what is being said. I've tagged ISO metric screw thread because the section has no references.  Screw also has no references, but it gives ISO metric screw thread as the main article.  However, it clearly isn't an accurate summary of the main article so I've tagged it as well.  I would argue that neither of these conventions are in widespread use and at least one is potentially confusing.  The whole section is a bit of a trainwreck since it is explicitly describing the use of threaded fasteners into nuts (ie. not screws).  In my experience metric bolts in the real world are almost universally described with an M, the nominal diameter, an x or times symbol, and the length of the bolt.  A pitch, if specified, is often but not always shown following a hyphen.  So M5x16, M10x80, and M12x25-1.25, for example.  M12x25x1.25 is also used, the slash notation seems more common with imperial bolts.  The standard might not agree with the real world though.  Lithopsian (talk) 19:44, 20 May 2021 (UTC)

Good for one screw
I am pretty sure that's a different kind of screw. https://picclick.com/SILVER-DOLLAR-HOTEL-Large-Brothel-Token-Denver-Colo-224200044859.html#&gid=1&pid=1 — Preceding unsigned comment added by 188.80.214.144 (talk) 18:32, 19 October 2020 (UTC)


 * Oy. 🙄 – AndyFielding (talk) 10:19, 23 May 2021 (UTC)

Allen screw history?
When a search for "Allen screw" directed me here, I was disappointed to find only an example and description of same—nothing on its history. Who was Allen? Is he destined to vanish in the mists of time? But it's a 20th-century invention, right? Its origins can't be that obscure, can they? As you can see, I have many questions. (In the interest of full disclosure, I live in a small town.) – AndyFielding (talk) 10:22, 23 May 2021 (UTC)


 * See Allen (brand) and also Allen key. Some of this information, or at least links to it, should perhaps be in this article.  Either that or allen screw should redirect somewhere better.  Lithopsian (talk) 19:19, 23 May 2021 (UTC)

Screws and bolts
Following on from discussions with another editor, I see two huge problems with this article. Neither are new and both have been discussed in the past, but not recently and never really resolved:

1. The article is titled Screw, a good WP:COMMONNAME. Unfortunately, a sizeable portion, not to say a majority, of the article is not about screws, but about bolts. Some of this is inevitable: it is hard to define a screw without mentioning what distinguishes it from a bolt, but the various tables and descriptions cover a whole bunch of things that aren't a screw by anyone's definition (eg. carriage bolts). So it seems there is a choice to be made: renamed the article; or gut it. Now would be a good time to voice opinions before I start anything formal or intrusive..

2. The definition of screw needs to be cleaned up. Again, you might say. The opening sentence of the article starts "A screw and a bolt ...", which should be a huge red flag. The existing article ties itself in huge knots by attempting to follow a fairly extreme definition of screw (which includes any bolt that isn't used with a nut), fostered by a particular interpretation of a very old reference book and some highly US-centric standards and legalistic (eg. customs and taxation) definitions (eg. ). A wider cleaner, definition might be good, but failing that either reword the existing definitions to be about screws or rename the article to cover both screws and bolts.

I'm aware that I'm opening a whole can of worms here. Read the archives for a great deal of background, even if most of it was a decade ago. There are some other articles that will inevitably need to be addressed, and could be considered to be part of the problem, whatever is done here: bolt (hardware), fastener, maybe threaded rod, etc.). Lithopsian (talk) 16:21, 16 March 2022 (UTC)