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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) [1]
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) [2]
References
The History section for "screw" writes that the "screw press" (hyperlinked to wiki entry for screw press [1]) 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)
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:
Gauge number | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 |
---|---|---|---|---|---|---|---|---|
Approximate diameter (mm) | 1.5 | 2.2 | 2.9 | 3.5 | 4.2 | 4.8 | 5.5 | 6.3 |
Source: [1]
There is also more valuable info on this site, such as
Let me know what you think. invenio tc 12:23, 1 June 2010 (UTC)
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)
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)
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)
Head markings and properties for metric hex-head cap screws[1] | |||||||||
---|---|---|---|---|---|---|---|---|---|
Head marking | Grade, material and condition | Nominal size range (mm) | Proof strength | Yield strength, min. | Tensile strength, min. | Core hardness (Rockwell) | |||
MPa | ksi | MPa | ksi | MPa | ksi | ||||
Class 3.6[2] | 1.6–36 | 180 | 26 | 190 | 28 | 330 | 48 | B52–95 | |
Class 4.6 Low or medium carbon steel |
5–100 | 225 | 32.6 | 240 | 35 | 400 | 58 | B67–95 | |
Class 4.8 Low or medium carbon steel; fully or partially annealed |
1.6–16 | 310 | 45 | 340 | 49 | 420 | 61 | B71–95 | |
Class 5.8 Low or medium carbon steel; cold worked |
5–24 | 380 | 55 | 420 | 61 | 520 | 75 | B82–95 | |
Class 8.8[3] Medium carbon steel; quench and tempered |
Under 16 (inc.) | 580 | 84 | 640 | 93 | 800 | 120 | ||
17–72 | 600 | 87 | 660 | 96 | 830 | 120 | C23–34 | ||
Class 8.8 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 8.8.3[4] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
ASTM A325M - Type 1[5][6] Medium carbon steel; quench and tempered |
12–36 | ||||||||
ASTM A325M - Type 3[5][6] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Class 9.8 Medium carbon steel; quench and tempered |
1.6–16 | 650 | 94 | 720 | 104 | 900 | 130 | C27–36 | |
Class 9.8 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 10.9 Alloy steel; quench and tempered |
5–100 | 830 | 120 | 940 | 136 | 1,040 | 151 | C33–39 | |
Class 10.9 low carbon Low carbon boron steel; quench and tempered | |||||||||
Class 10.9.3[4] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
ASTM A490M - Type 1[5][7] Alloy steel; quench and tempered |
12–36 | ||||||||
ASTM A490M - Type 3[5][7] Atmospheric corrosion resistant steel; quench and tempered | |||||||||
Class 12.9 Alloy steel; quench and tempered |
1.6–100 | 970 | 141 | 1,100 | 160 | 1,220 | 177 | C38–44 | |
A2[3] Stainless steel with 17–19% chromium and 8–13% nickel |
up to 20 | 210 minimum 450 typical |
30 minimum 65 typical |
500 minimum 700 typical |
73 minimum 100 typical |
||||
ISO 3506-1 A2-50[citation needed] 304 stainless steel-class 50 (annealed) |
210 | 30 | 500 | 73 | |||||
ISO 3506-1 A2-70[citation needed] 304 stainless steel-class 70 (cold worked) |
450 | 65 | 700 | 100 | |||||
ISO 3506-1 A2-80[citation needed] 304 stainless steel-class 80 |
600 | 87 | 800 | 120 |
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Peter Horn User talk 13:33, 18 April 2019 (UTC)
Peter Horn, 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)
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)
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, <<A crude, but easy to remember, distinction would be, "A bolt takes a nut, a screw does not.">>
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)
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)
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)
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)
https://www.youtube.com/watch?v=M99gtHeCBb4 says their Lag screws were hammered in until the last few turns. Can anyone confirm? Wizzy…☎ 16:58, 27 April 2020 (UTC)
Here, in the Screw#ISO metric screw thread 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#Designation 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)
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)
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)
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. [5]). 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)