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Also, the picture of the Carriage Bolt is labeled in error; the square shank is directly below the bolthead, then there is a round, unthreaded shank, followed by the threaded section. Acey-Deucy 16:57, 28 December 2006 (UTC)
The bolt picture is valid as there are several types of bolts, each of which have several types of geometrical features present along there shank. This picture could be said to be one of the more general cases which features the commonly found features on a bolt.
The text also seems to be missing the information pertaining to the labeling 1, 2, 3, 4 A diagram of a carriage bolt. 1. Bolt head 2. Round part 3. Square part (or carriage) 4. Bolt threads —Preceding unsigned comment added by 61.90.18.43 ( talk) 04:00, 15 February 2011 (UTC)
I note that all the pan head screws I have seen actually have a chamfered/rounded lower edge to the head (it makes sense since the screw is pressed rather than cut). You can just see it in the pictures here: http://www.indiamart.com/chintamani-industries/machine-screws.html, or here: http://img-asia.electrocomponents.com/catimages/R5465604-29.jpg, but for some reason it is rarely shown on diagrams. — Preceding unsigned comment added by 203.206.162.148 ( talk) 12:03, 19 September 2011 (UTC)
All this info was lost in the merger/redirect: [click "show" at right to view]
A wood screw is defined as a male screw made of a metal with a slotted head and sharp point. A wood screw is commonly furnished with a flat, round or oval-head.
In the manufacturing of wood screws, normally, steel with low carbon contents is used as a metal, manufactured by steel mills in the shape of billets which are purchased by wire rod manufacturing mills. This wire rod is further drawn by wire drawing units into different sizes of wire, required by screw or fastener manufacturers. Drawn wire has a variety of other uses as well.
A wood screw passes through the following processes before coming to the packing department in a wood screw manufacturing factory where three separate machines are used for heading, slotting and threading to manufacture wood screws.
This process is called
cold forging. Wire coil is put on a stand and wire is fed into a heading machine known as the Header. This wire should not be rusty. The wire is cut into a specified size by a cutting mechanism and is pushed forward towards a die hole. A punch, fixed on a moving block, punches this wire into a die made of
Carbide, encased by a protective steel covering or a die of any other suitable material to make a plug. Then a second punch presses this plug to form a blank. The shape of the head is formed according to the design of the second punch. For a flat head wood screw, a flat punch is fixed. Half round or phillips head wood screws are manufactured by grooving or embossing the shape as required on second punch. When the blank is made, a pin moving in the round die, pushes the blank out. This heading machine is also known as the Double-stroke Header. Frequent lubrication is necessary to all parts of the heading machine. Before introduction of the Double-stroke Heading machines, Single-stroke Headers were used to make blanks but are obsolete now.
For the working of a Single-stroke header or "former" see also
bolt manufacturing process.
Blanks made by the heading machine are transferred to the slotting machine after polishing. Polishing is a necessary process to clean oil, dust or rust from the blanks. Rust or corrosion can damage or reduce the life of the cutter used to make slots. Blanks are put in the hopper fixed on the slotting machine, and they slide down through railing towards the rotating grooved dial which moves them towards the round cutter which is fixed on rotating adjustable shaft. Regarding the cutting speed, it is constantly proportion to the rotation of the dial. The cutter is controlled by a separate motor in some other models of slotting machines. The cutter makes the slot in the centre of the blank's head. When the blanks reach down they are dropped. Continuous lubrication is needed to increase life of the cutter. The process of slotting is skipped when the slot is made on the head by second punch on the heading machine. Slotting machines perform their function at high speed reaching up to 1600 pcs per minute (theoretically). In practice, however, a much less number of pieces is manufactured than claimed by the manufacturers of machines.
Threads are made either by rolling or cutting.
After being polished the blanks are put in the hopper fixed on the threading machine, and they slide down the railing towards dies. Two flat dies are used, one is stationary and other is moving and the rolling faces of the dies are located opposite each other. One blank at a time is pushed towards the dies with the help of a plate known as the feeding or the starter finger.
When it is gripped between hardened steel dies, the moving die rotates it and threads are formed(see notes 1) and a point(see notes 2) is made as per threading dies. The moving die is fixed in a die pocket on the block which moves further ahead and the screw is dropped(see notes 3). Threading machines perform their function at a high speed. The process is called cold forming and continuous lubrication is required to keep the dies below certain temperature.
The other method of making threads is cut-thread. These machines are different form Thread-rolling machines. Blanks slide though rail from the hopper (different than the hopper used in thread rolling machines) and are gripped by feeding finger one by one. The feeding finger presses down and pushes the blank into spindle head and moves up to grip the next blank. The timing of this mechanism is controlled by gears and a rotating cam along with other cams. As soon as the spindle head is closed, and the head of blank is gripped, a cutting tool moves forward to cut the other side of blank to make a point. While this tool is moving back, another tool fixed on a shaft starts cutting the threads. Cutting of threads is a three to five steps process depending upon the length and the diameter of blank. When the threads are cut and the spindle is opened, the feeding finger comes down, pulls out the screw, feeds in the next blank, moves up and before it reaches its original position, a shoot ahead part takes the screw from it.
Polishing of blanks is repeated after they are made, slotted and threaded. A hexagonal steel drum is used for blanks polishing and a hexagonal drum made of wood is used for polishing after threads are cut or formed. Wood and leather waste is jointly or separately put inside the drum along with blanks in humid weather. Wood waste alone can do the work in dry weather. When these drums rotate, wood and leather waste absorb oil and continuous rubbing cleans and polishes the surface of blanks and screws.
The process of hot-dip galvanizing, blackening or coating is done only when it is required by wholesalers, retailers or is desired by users.
{{DEFAULTSORT:Wood Screw Manufacturing}} [[Category:Metalworking]] [[Category:Screws]]
It might have been useful to retain this info. Peter Horn User talk 02:19, 16 February 2011 (UTC)
I came to this page looking for information on the size markings of woodscrews, but there is nothing. Please would someone add this ?
Also, I would like to propose that the woodscrew information that was deleted should be fully restored, as it is both important and interesting. This could either be on this page, or on a page devoted to woodscews, considering the vast amount of information on all types that has been accumulated to date. Darkman101 ( talk) 01:00, 26 July 2012 (UTC)
I made the changes for the following reasons: The section was overly specific about what a screw and bolt were: a. some bolts don't have heads designed to be driven. b. some screws don't have heads or at least external heads (set screws). c. threaded fasteners can mate with complementary helixes formed in other ways than tapping.
I realize that the section now repeats some of the opening. This seems a bit awkward and perhaps somebody could improve on the way I did it.
Part of the awkwardness is the title of this article. A long time ago I changed the title of the article to Screws and bolts or Screw/bolts. Somebody came through and changed it back without giving a reason. I still think the article should be titled, Screws and bolts. Long before me, this article morphed into an article describing screws and bolts and I don't see why it's not called that. —Preceding unsigned comment added by Davefoc ( talk • contribs) 17:06, 6 May 2009 (UTC)
The impetus for the changes was the change made by 205.179.219.242. I think this is what he had in mind with his parenthetical comment. -- Davefoc ( talk) 17:42, 6 May 2009 (UTC)
I left the term, self tapping, in place. Perhaps self threading would be better though. Self tapping is generally applied to screws designed for use with sheet metal and plastic. The machinery's handbook uses the term, self threading for the general class of threaded fasteners that form their own threads as they are driven. Davefoc ( talk) 17:35, 6 May 2009 (UTC)
I notice that somebody deleted the whole section and the delete was reverted. In some ways the delete makes sense, IMHO. Part of this section could be used as an intro at the top of this article, combined with the part that is there now in some way or just deleted. This especially makes sense if the title of the article was changed to "Screws and bolts". Other parts of this section might get their own title like the issue of left and right handedness and the issues of rolled versus cut threads. That part needs some changes anyway because it is misleading to call rolled threads a recent advance. Davefoc ( talk) 21:12, 6 May 2009 (UTC)
Minor edits for clarity. Davefoc ( talk) 21:18, 6 May 2009 (UTC)
I note almost universal usage of "Phillips" within the text to descripe the more generic cross-recess drive type. Phillips is a trademarked name and as such refers to a specific manufacturer's product. While many patents have expired, the correct term is "cross-recess". Phillips, JIS, JCIS and others are sub-types of cross-recess drive. Ken ( talk) 20:55, 4 March 2013 (UTC)
The citation was removed and a hidden note was added to the source. The note, by wizard191, says that he doubts that the alternative definition for bolt and screw listed in the link exists.
I disagree a bit. Keithonearth believed that this was the distinction in the long discussions about that section. I suspect other people have arrived at a similar idea. It might be the most rational way to define the terms. I used the reference to prove that there is some support for this distinction. The section goes on to explain that the distinction is not one that is consistent with general use or formal specification. I suspect that this may be the only reference to such a distinction on the internet, but given my general sense that at least some people believe that it is correct I thought it was reasonable to discuss it in the article. As such, I thought the section was useful as it stood and didn't need to be changed. -- Davefoc ( talk) 13:56, 25 May 2009 (UTC)
We had this discussion long ago. I was concerned about the use of a questionable source and you suggested that I shouldn't use it. In general, I suspect we have similar ideas about what a reliable source is and for most purposes this kind of source would certainly not qualify as reliable. However, in this case, this source provides a reliable data point that at least somebody holds this view. Some credibility to the idea that these kind of definitions of screw and bolt exist beyond the existence of the data from this web site is that Keithonearth argued strongly for a similar definition. For me the issue is whether the view is held widely enough to justify addressing it in this Wikipedia article. I don't know the answer to that. It seems like a logical view that some people are going to come to on their own and it is reasonable to address it just for that reason, but I don't have a strong feeling about this and maybe the idea is just too obscure to be worth addressing in this article. -- Davefoc ( talk) 20:51, 25 May 2009 (UTC)
Davefoc ( talk) 05:30, 8 June 2009 (UTC)
I fear that the difference between a bolt and a screw may not be defineable. The definition of being able to receive a nut for bolt seems good, but I remember buying machine screws for work that fit the definition of bolt. Perhaps bolts are a subset of screws. Usage may be arbitrary as in motor/engine. -- Weetoddid ( talk) 22:49, 6 June 2009 (UTC)
I've added back the "alternative" definition and the link to the Structural Analysis Reference Library. It has every appearance of being a sensible reference work, and the superior usefulness and logic of the definition should tip the balance of any debate in favour of inclusion. There is obviously no descriptive definition for either term that will fit every fastener that has ever been called a screw or a bolt. The ambiguity of the terms is a vicious circle - people called a "machine screw" a screw because an ambiguity existed, and now the ambiguity is entrenched. The "alternative" definition most certainly is not descriptive, in the sense that it doesn't describe how everyone uses the two terms. But it serves as the most useful prescriptive definition - suggesting how the terms should (or at least could) sensibly be used. —Preceding unsigned comment added by Michael S G 82.152.203.195 ( talk) 02:03, 12 May 2010 (UTC)
The nominal thread length, for reference and calculation purposes, for bolts is as follows:
If the bolt length less than or equal to 6", the nominal thread length is calculated as (Diameter X 2) + 0.25. If the bolt length is greater than 6", the nominal thread length is calculated as (Diameter x 2) + 0.50.
Note: Thread lengths specified above are the minimum required thread lengths to be supplied if a thread length is not specified.
Bolts have one smooth diameter which fits closely in the hole to prevent fatigue and are torqued to plasticity to stop vibration causing fatigue cracking, two diameters plus of thread length is for one nut and a lock nut. Anything threaded the entire or nearly the entire length is a screw, tapered or not. This means some short bolts could be called screws, but look at the thickness of the shank. A good bolt MUST have a washer to support the nut because the thread top is level with the shank, nuts would grind into the surface metal. The same applies to coach bolts (putting a washer under the head defeats the purpose of the head, and omitting the large washers means the nut just pulls into the wood) Lag bolts are a slight variant but the same principle, the (usually)screw end replaces the threaded end to both put tension in the bolt and open the lag shields to anchor them in the concrete. The not-threaded /not-screw length can of course be any length. Machine screws are just that, essentially fully threaded constant diameter fasteners, not intended to be used with nuts but threaded holes. Spaghettij ( talk) 16:27, 8 April 2013 (UTC)
205.243.112.50 changed the opening section so as to directly quote ASME B18.12 as to what the difference between a screw and a bolt is. The previous version quoted the distinction listed in the Machinery's handbook which I believe was derived from ASME B18.12. That seems to be an improvement in that a primary instead of a secondary source is quoted.
However I reverted his change overall, because:
I thought that ideas as to possible changes to the section had some merit. Perhaps the paragraph should start out with the ASME B18.12 distinction. It should then follow that up with a sentence that explains that not all fasteners can be unambiguously determined to be a bolt or a screw using the ASME B18.12 distinction. Davefoc ( talk) 05:35, 13 October 2009 (UTC)
Reverting this change was a mistake. The language maybe should have been cleaned up but this edit actually provided the real, verifiable, source appropriate definition of the differences between a screw and a bolt. There are standards organizations throughout the world that are composed of industry experts. ANSI is the nationially accepted standards organziation in the USA. They are the definitive authority on such things as fastener standardization. ANSI, simplistically, farms the standardization of fasteners out to ASME. ASME is the clear authority when it comes to defining the difference between bolts and screws. All relative fastener organizations (ASME B18, ASTM F16, ISO TC/2, etc...) agree on the ASME B18.12 definition. There is not a single reference in any fastener technical publication anywhere to Machinery's Handbook. It is not an authority on the subject and is frequently representative of out of date information. I am willing to clean this up if it isn't going to be changed right back to inferior references like the Machinery's Handbook. (chwillia1) — Preceding unsigned comment added by Chwillia1 ( talk • contribs) 21:56, 28 November 2012 (UTC)
In general, I oppose the removal of material solely because it is "obvious" -- see WP:OBVIOUS. I also even more strongly oppose deleting references to relevant standards organizations because of writing issues such as "The wording might be improved" or "It fails to provide a lead in". Such writing issues are relatively easy to fix once the information is in the article. All too many Wikipedia articles lack good references -- which seems to indicate that a lack of references is relatively difficult to fix. -- DavidCary ( talk) 01:56, 21 July 2013 (UTC)
I came here looking for a Woodscrew Size Conversion Chart, between metric and screw number sizes. Please can anyone add a chart or a link to one ? Many thanks ! Darkman101 ( talk) 19:32, 7 August 2013 (UTC)
I think the order of sections in this article is a bit odd. I would have expected history to be first, followed by types of screws. It seems strange to me to have "differentiation of screws and bolts" as the first section. I don't think the majority of people come to this page looking to learn about the differences between screws and bolts; I'd imagine that history of screws and screw types are the most frequently sought after sections. — Preceding unsigned comment added by Blelbach ( talk • contribs) 05:34, 19 October 2013 (UTC)
I am finding this page confusing or at least not confidence-inspiring because differences between various national or international standards are not made clear. For example, wood screw gauge is a number in the US and the UK. But is it the same number? Are US inches even the same as UK inches? The page doesn't say, and it refers to gauges without saying which system they come from. Hence, my lack of confidence in the information in this page ... yes, yes, I should add this info myself. But it's not my area of competence, which is why I came here in the first place. 87.113.51.124 ( talk) 10:29, 18 March 2014 (UTC)
What does everyone think of converting the types of screws section into a table format, like the one at wrench, so that images can be included with the descriptions? I think its a cleaner layout as well. Wizard191 ( talk) 16:05, 31 December 2010 (UTC)
The definitions under Cap Screw are incorrect (albeit very minor): "A socket cap screw, also known as a socket head capscrew, socket screw, "set screw" or Allen bolt, is a type of cap screw with a cylindrical head and hexagonal drive hole."
We are choosing some screws for metal door use, and would like to find the mark's means. Thanks in advance. — Preceding unsigned comment added by 183.26.40.117 ( talk) 01:06, 7 December 2013 (UTC)
73.185.194.135, you're mixing some things together in your mind, some of which are true trends and some of which are scary extrapolations of those trends into frightful ghosts. To start, you're conflating (1) the total variety of what existed on earth 40 years ago versus (2) which subset of it that you saw at that time, based on the particular books and periodicals you were looking at (a subset of what existed). You say "The H for head was never used", and yet I just showed you scanned copies, scanned directly from printed books and magazines from 1910 and from 1970, of people using it. Your idea that "it didn't exist at that time" is wrong, which is verified using printed books and magazines from that time (despite your fear that all such printed works are equally lost). Please understand that I'm not picking on you, either. I am just duly defending the valid info that is collected here and pointing out the aspects of what you're crusading about that are misextrapolated. You should breathe easier knowing that the misinformation that the ignorant kids share online today is often more falsifiable than your fears suggest. The stuff that's wrong (as in counterfactual) is quite often exposed sooner or later. As for what's "wrong" as in "things people do that you wish they didn't"—rest assured that that's been going on since long before the internet. It is certain that many American machinists and hardware dealers were using 'H' for 'head' in the 20th century (which the 1910 book gives evidence of, and which I encountered personally in the 1990s). This article covers the terms that machinists and hardware dealers use just as much as it covers the recommended nomenclature of engineering societies. You've taken a legitimate general concern about how experts interact with amateurs since the advent of the Web (these damn kids mostly don't even look at printed works anymore) and extrapolated it in your mind into a bit more of a monster than it is (fortunately, there are [literally] millions of printed works at everyone's fingertips at http://books.google.com/advanced_book_search and https://books.google.com/ngrams/—people may not get engineering books out of the library much these days, but OCRd scans of millions of those books are available online for falsifying wrong ideas). Nothing in this article contradicts reality, either of today or decades past. If there's a piece of reality missing, feel free to add it. But your idea "The H for head was never used 40 years ago" isn't reality. It would have to be modified to "no standardized engineering nomenclature used 'H' for 'head' 40 years ago" in order to be a piece of reality. And you could probably point to multiple MIL standards, ASTM standards, SAE standards, and British Standards that don't use the 'H' in their nomenclature. As for the idea that "standards don't exist anymore", that's actually completely wrong—there are a shitload of standards that manufacturers currently have to comply with (ASTM, SAE, NAS/AS/AIA, the many active MIL standards, ISO, FDA, and many others). The boobs chatting on Yahoo aren't consulting them, but people in the manufacturing industries are damn sure consulting them every day, at sites like this, where they pay through the wazoo for copyright-protected PDFs of them (although a lot of sharing of copies on the down-low happens, too). Your idea (paraphrased) that "nothing that was printed back then is ever looked at now" is a misextrapolation; although that is often true, the links above are some of the instances when it is not. You may have a belief that "the best engineers didn't use the H", but that is different from "it didn't exist." Regarding "We have no rockets to fly to space because standards are lost and the ability to produce such a rocket is gone"—Although it is well publicized that a lot of institutional memory from the Saturn V era is lost thanks to people getting older and passing away, paper files being discarded or crumbling away, the damn kids and their video games, and so on, the idea that the news media drums into our heads—about some planet of the apes type of loss of technology—is something that they do on purpose to rile people up into a worried, angry froth. Much of it is clickbait, but some of the people churning it out believe it, too, because many of them have little accurate understanding of the topic. Here is a news story closer to the truth of what is happening in terms of future space tech. It's not all just a bunch of apes clambering over the half-buried Statue of Liberty. To sum up, don't let the media scare you into believing an evil-clown caricature of what really is happening. Yes, good information gets lost or siloed. But the aerospace, defense, and medical device industries are still cranking out high-tech stuff. And if the people who hold the purse strings ever decide to build a new Saturn-type rocket, you better believe that Boeing and Lockheed and their legions of suppliers will reinvent one that works, for enough billions of dollars. Of course, we'd better tend to the economic underpinning of that, though, if we want any billions to exist. So squashing the middle class (and thus cratering our economy) is not in the MIC's own interests, and hopefully they will realize it eventually. — ¾-10 23:22, 26 August 2014 (UTC)
This article currently defines "shank" with a good reference. Great!
Unfortunately, this article currently uses "shaft" a few times without illustrating or defining the term.
I was on the verge of editing the article to say that "shaft" and "shank" are synonyms, as a result of the above " #What does shank mean?" discussion.
But then I came across one website [1] that seems to say that (paraphrasing): The shaft is the smooth, unthreaded section from the underside of the head to the start of the threaded section. The shaft is only a small part of the shank.
Can we get reliable sources defining "shaft"? -- DavidCary ( talk) 00:13, 13 February 2015 (UTC)
Is a worm screw another name for a set screw (aka a grub screw)? Should it be added? — Preceding unsigned comment added by 81.107.32.7 ( talk) 07:47, 17 February 2015 (UTC)
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From the opening section:
Some screws have an unthreaded portion of the shaft under the head, which is known as the shank.
In every other place the word shank is use it sounds like it means shaft. For instance:
Fasteners with a non-tapered shank are designed to mate with a nut or to be driven into a tapped hole.
The word shaft was replaced with the word shank throughout the article. That seemed to make sense if shank means shaft with regards to screws. Shank seems like a more specialized fastener type word. But if shank actually means the unthreaded part of the shaft then consideration might be given to modifying at least some of the sentences that use it to mean the whole shaft.
The nail article defines shank as:
the body the length of the nail between the head and the point; may be smooth, or may have rings or spirals for greater holding power
It seems like shank=shaft when it comes to screws. I would like to have confirmed that with a dictionary definition but the definitions I saw didn't cover this issue, at least not unambiguously. What is the source for the definition of shank provided in the opening paragraph? -- Davefoc ( talk) 10:19, 18 September 2009 (UTC)
D. Shank-the cylindrical part of a bolt that extends from the underside of the head to the point.
I cannot recall ever seeing 'shaft' used in this manner; 'shank' is the right term. —Preceding unsigned comment added by 72.72.20.207 ( talk) 17:43, 20 January 2010 (UTC)
From ISO 1891 Fasteners -- Terminology, it is clear that shank is the unthreaded part. It is synonymous with 'body'. Other reference: https://www.boltdepot.com/fastener-information/terminology.aspx — Preceding unsigned comment added by 84.196.104.49 ( talk) 14:41, 19 April 2015 (UTC)
A new editor, Glooop, made the following addition to the introduction, but not in the right place. Perhaps it can be worked into a scientific description:
Amandajm ( talk) 06:02, 31 March 2012 (UTC)
No, its not. this more closely defines a screw thread but not a screw. — Preceding unsigned comment added by 205.243.112.221 ( talk) 21:11, 28 November 2012 (UTC)
"A screw in its most general form is one of the Simple machines of Renaissance times, and when used as a fastener the concept of an inclined plane explains how relatively little force/ torque applied to a screwdriver may provide a fastening capable of withstanding high [[Stress (mechanics)|stresses]"
I also think it would be helpful to include some wording around this point to explain screws may have uniform (diameter & pitch) threads (e.g. grub screws) or have tapered threads (e.g. wood screws). Maitchy ( talk) 01:01, 9 February 2016 (UTC)
When was the wood screw developed? The nut-and-bolt? When did they become cheap enough for common use? Paul, in Saudi ( talk) 14:18, 1 November 2013 (UTC)
Actually the assertion that wood screw wer quite ancient is unsupported. The cited source states that screws as fasteners were first developed in Europe in the 15th century. The history section contains some imaginative misrepresentation of that cited source. 184.45.21.70 ( talk) 16:47, 25 March 2016 (UTC)
This article says that coach screw and coach bolt are synonymous but different from a carriage bolt and is in conflict with Carriage bolt where a carriage or coach bolt are synonymous and are retained by a nut as opposed to a coach screw. As I suggest it should be. Cinderella157 ( talk) 06:13, 31 January 2017 (UTC)
![]() | This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 |
Also, the picture of the Carriage Bolt is labeled in error; the square shank is directly below the bolthead, then there is a round, unthreaded shank, followed by the threaded section. Acey-Deucy 16:57, 28 December 2006 (UTC)
The bolt picture is valid as there are several types of bolts, each of which have several types of geometrical features present along there shank. This picture could be said to be one of the more general cases which features the commonly found features on a bolt.
The text also seems to be missing the information pertaining to the labeling 1, 2, 3, 4 A diagram of a carriage bolt. 1. Bolt head 2. Round part 3. Square part (or carriage) 4. Bolt threads —Preceding unsigned comment added by 61.90.18.43 ( talk) 04:00, 15 February 2011 (UTC)
I note that all the pan head screws I have seen actually have a chamfered/rounded lower edge to the head (it makes sense since the screw is pressed rather than cut). You can just see it in the pictures here: http://www.indiamart.com/chintamani-industries/machine-screws.html, or here: http://img-asia.electrocomponents.com/catimages/R5465604-29.jpg, but for some reason it is rarely shown on diagrams. — Preceding unsigned comment added by 203.206.162.148 ( talk) 12:03, 19 September 2011 (UTC)
All this info was lost in the merger/redirect: [click "show" at right to view]
A wood screw is defined as a male screw made of a metal with a slotted head and sharp point. A wood screw is commonly furnished with a flat, round or oval-head.
In the manufacturing of wood screws, normally, steel with low carbon contents is used as a metal, manufactured by steel mills in the shape of billets which are purchased by wire rod manufacturing mills. This wire rod is further drawn by wire drawing units into different sizes of wire, required by screw or fastener manufacturers. Drawn wire has a variety of other uses as well.
A wood screw passes through the following processes before coming to the packing department in a wood screw manufacturing factory where three separate machines are used for heading, slotting and threading to manufacture wood screws.
This process is called
cold forging. Wire coil is put on a stand and wire is fed into a heading machine known as the Header. This wire should not be rusty. The wire is cut into a specified size by a cutting mechanism and is pushed forward towards a die hole. A punch, fixed on a moving block, punches this wire into a die made of
Carbide, encased by a protective steel covering or a die of any other suitable material to make a plug. Then a second punch presses this plug to form a blank. The shape of the head is formed according to the design of the second punch. For a flat head wood screw, a flat punch is fixed. Half round or phillips head wood screws are manufactured by grooving or embossing the shape as required on second punch. When the blank is made, a pin moving in the round die, pushes the blank out. This heading machine is also known as the Double-stroke Header. Frequent lubrication is necessary to all parts of the heading machine. Before introduction of the Double-stroke Heading machines, Single-stroke Headers were used to make blanks but are obsolete now.
For the working of a Single-stroke header or "former" see also
bolt manufacturing process.
Blanks made by the heading machine are transferred to the slotting machine after polishing. Polishing is a necessary process to clean oil, dust or rust from the blanks. Rust or corrosion can damage or reduce the life of the cutter used to make slots. Blanks are put in the hopper fixed on the slotting machine, and they slide down through railing towards the rotating grooved dial which moves them towards the round cutter which is fixed on rotating adjustable shaft. Regarding the cutting speed, it is constantly proportion to the rotation of the dial. The cutter is controlled by a separate motor in some other models of slotting machines. The cutter makes the slot in the centre of the blank's head. When the blanks reach down they are dropped. Continuous lubrication is needed to increase life of the cutter. The process of slotting is skipped when the slot is made on the head by second punch on the heading machine. Slotting machines perform their function at high speed reaching up to 1600 pcs per minute (theoretically). In practice, however, a much less number of pieces is manufactured than claimed by the manufacturers of machines.
Threads are made either by rolling or cutting.
After being polished the blanks are put in the hopper fixed on the threading machine, and they slide down the railing towards dies. Two flat dies are used, one is stationary and other is moving and the rolling faces of the dies are located opposite each other. One blank at a time is pushed towards the dies with the help of a plate known as the feeding or the starter finger.
When it is gripped between hardened steel dies, the moving die rotates it and threads are formed(see notes 1) and a point(see notes 2) is made as per threading dies. The moving die is fixed in a die pocket on the block which moves further ahead and the screw is dropped(see notes 3). Threading machines perform their function at a high speed. The process is called cold forming and continuous lubrication is required to keep the dies below certain temperature.
The other method of making threads is cut-thread. These machines are different form Thread-rolling machines. Blanks slide though rail from the hopper (different than the hopper used in thread rolling machines) and are gripped by feeding finger one by one. The feeding finger presses down and pushes the blank into spindle head and moves up to grip the next blank. The timing of this mechanism is controlled by gears and a rotating cam along with other cams. As soon as the spindle head is closed, and the head of blank is gripped, a cutting tool moves forward to cut the other side of blank to make a point. While this tool is moving back, another tool fixed on a shaft starts cutting the threads. Cutting of threads is a three to five steps process depending upon the length and the diameter of blank. When the threads are cut and the spindle is opened, the feeding finger comes down, pulls out the screw, feeds in the next blank, moves up and before it reaches its original position, a shoot ahead part takes the screw from it.
Polishing of blanks is repeated after they are made, slotted and threaded. A hexagonal steel drum is used for blanks polishing and a hexagonal drum made of wood is used for polishing after threads are cut or formed. Wood and leather waste is jointly or separately put inside the drum along with blanks in humid weather. Wood waste alone can do the work in dry weather. When these drums rotate, wood and leather waste absorb oil and continuous rubbing cleans and polishes the surface of blanks and screws.
The process of hot-dip galvanizing, blackening or coating is done only when it is required by wholesalers, retailers or is desired by users.
{{DEFAULTSORT:Wood Screw Manufacturing}} [[Category:Metalworking]] [[Category:Screws]]
It might have been useful to retain this info. Peter Horn User talk 02:19, 16 February 2011 (UTC)
I came to this page looking for information on the size markings of woodscrews, but there is nothing. Please would someone add this ?
Also, I would like to propose that the woodscrew information that was deleted should be fully restored, as it is both important and interesting. This could either be on this page, or on a page devoted to woodscews, considering the vast amount of information on all types that has been accumulated to date. Darkman101 ( talk) 01:00, 26 July 2012 (UTC)
I made the changes for the following reasons: The section was overly specific about what a screw and bolt were: a. some bolts don't have heads designed to be driven. b. some screws don't have heads or at least external heads (set screws). c. threaded fasteners can mate with complementary helixes formed in other ways than tapping.
I realize that the section now repeats some of the opening. This seems a bit awkward and perhaps somebody could improve on the way I did it.
Part of the awkwardness is the title of this article. A long time ago I changed the title of the article to Screws and bolts or Screw/bolts. Somebody came through and changed it back without giving a reason. I still think the article should be titled, Screws and bolts. Long before me, this article morphed into an article describing screws and bolts and I don't see why it's not called that. —Preceding unsigned comment added by Davefoc ( talk • contribs) 17:06, 6 May 2009 (UTC)
The impetus for the changes was the change made by 205.179.219.242. I think this is what he had in mind with his parenthetical comment. -- Davefoc ( talk) 17:42, 6 May 2009 (UTC)
I left the term, self tapping, in place. Perhaps self threading would be better though. Self tapping is generally applied to screws designed for use with sheet metal and plastic. The machinery's handbook uses the term, self threading for the general class of threaded fasteners that form their own threads as they are driven. Davefoc ( talk) 17:35, 6 May 2009 (UTC)
I notice that somebody deleted the whole section and the delete was reverted. In some ways the delete makes sense, IMHO. Part of this section could be used as an intro at the top of this article, combined with the part that is there now in some way or just deleted. This especially makes sense if the title of the article was changed to "Screws and bolts". Other parts of this section might get their own title like the issue of left and right handedness and the issues of rolled versus cut threads. That part needs some changes anyway because it is misleading to call rolled threads a recent advance. Davefoc ( talk) 21:12, 6 May 2009 (UTC)
Minor edits for clarity. Davefoc ( talk) 21:18, 6 May 2009 (UTC)
I note almost universal usage of "Phillips" within the text to descripe the more generic cross-recess drive type. Phillips is a trademarked name and as such refers to a specific manufacturer's product. While many patents have expired, the correct term is "cross-recess". Phillips, JIS, JCIS and others are sub-types of cross-recess drive. Ken ( talk) 20:55, 4 March 2013 (UTC)
The citation was removed and a hidden note was added to the source. The note, by wizard191, says that he doubts that the alternative definition for bolt and screw listed in the link exists.
I disagree a bit. Keithonearth believed that this was the distinction in the long discussions about that section. I suspect other people have arrived at a similar idea. It might be the most rational way to define the terms. I used the reference to prove that there is some support for this distinction. The section goes on to explain that the distinction is not one that is consistent with general use or formal specification. I suspect that this may be the only reference to such a distinction on the internet, but given my general sense that at least some people believe that it is correct I thought it was reasonable to discuss it in the article. As such, I thought the section was useful as it stood and didn't need to be changed. -- Davefoc ( talk) 13:56, 25 May 2009 (UTC)
We had this discussion long ago. I was concerned about the use of a questionable source and you suggested that I shouldn't use it. In general, I suspect we have similar ideas about what a reliable source is and for most purposes this kind of source would certainly not qualify as reliable. However, in this case, this source provides a reliable data point that at least somebody holds this view. Some credibility to the idea that these kind of definitions of screw and bolt exist beyond the existence of the data from this web site is that Keithonearth argued strongly for a similar definition. For me the issue is whether the view is held widely enough to justify addressing it in this Wikipedia article. I don't know the answer to that. It seems like a logical view that some people are going to come to on their own and it is reasonable to address it just for that reason, but I don't have a strong feeling about this and maybe the idea is just too obscure to be worth addressing in this article. -- Davefoc ( talk) 20:51, 25 May 2009 (UTC)
Davefoc ( talk) 05:30, 8 June 2009 (UTC)
I fear that the difference between a bolt and a screw may not be defineable. The definition of being able to receive a nut for bolt seems good, but I remember buying machine screws for work that fit the definition of bolt. Perhaps bolts are a subset of screws. Usage may be arbitrary as in motor/engine. -- Weetoddid ( talk) 22:49, 6 June 2009 (UTC)
I've added back the "alternative" definition and the link to the Structural Analysis Reference Library. It has every appearance of being a sensible reference work, and the superior usefulness and logic of the definition should tip the balance of any debate in favour of inclusion. There is obviously no descriptive definition for either term that will fit every fastener that has ever been called a screw or a bolt. The ambiguity of the terms is a vicious circle - people called a "machine screw" a screw because an ambiguity existed, and now the ambiguity is entrenched. The "alternative" definition most certainly is not descriptive, in the sense that it doesn't describe how everyone uses the two terms. But it serves as the most useful prescriptive definition - suggesting how the terms should (or at least could) sensibly be used. —Preceding unsigned comment added by Michael S G 82.152.203.195 ( talk) 02:03, 12 May 2010 (UTC)
The nominal thread length, for reference and calculation purposes, for bolts is as follows:
If the bolt length less than or equal to 6", the nominal thread length is calculated as (Diameter X 2) + 0.25. If the bolt length is greater than 6", the nominal thread length is calculated as (Diameter x 2) + 0.50.
Note: Thread lengths specified above are the minimum required thread lengths to be supplied if a thread length is not specified.
Bolts have one smooth diameter which fits closely in the hole to prevent fatigue and are torqued to plasticity to stop vibration causing fatigue cracking, two diameters plus of thread length is for one nut and a lock nut. Anything threaded the entire or nearly the entire length is a screw, tapered or not. This means some short bolts could be called screws, but look at the thickness of the shank. A good bolt MUST have a washer to support the nut because the thread top is level with the shank, nuts would grind into the surface metal. The same applies to coach bolts (putting a washer under the head defeats the purpose of the head, and omitting the large washers means the nut just pulls into the wood) Lag bolts are a slight variant but the same principle, the (usually)screw end replaces the threaded end to both put tension in the bolt and open the lag shields to anchor them in the concrete. The not-threaded /not-screw length can of course be any length. Machine screws are just that, essentially fully threaded constant diameter fasteners, not intended to be used with nuts but threaded holes. Spaghettij ( talk) 16:27, 8 April 2013 (UTC)
205.243.112.50 changed the opening section so as to directly quote ASME B18.12 as to what the difference between a screw and a bolt is. The previous version quoted the distinction listed in the Machinery's handbook which I believe was derived from ASME B18.12. That seems to be an improvement in that a primary instead of a secondary source is quoted.
However I reverted his change overall, because:
I thought that ideas as to possible changes to the section had some merit. Perhaps the paragraph should start out with the ASME B18.12 distinction. It should then follow that up with a sentence that explains that not all fasteners can be unambiguously determined to be a bolt or a screw using the ASME B18.12 distinction. Davefoc ( talk) 05:35, 13 October 2009 (UTC)
Reverting this change was a mistake. The language maybe should have been cleaned up but this edit actually provided the real, verifiable, source appropriate definition of the differences between a screw and a bolt. There are standards organizations throughout the world that are composed of industry experts. ANSI is the nationially accepted standards organziation in the USA. They are the definitive authority on such things as fastener standardization. ANSI, simplistically, farms the standardization of fasteners out to ASME. ASME is the clear authority when it comes to defining the difference between bolts and screws. All relative fastener organizations (ASME B18, ASTM F16, ISO TC/2, etc...) agree on the ASME B18.12 definition. There is not a single reference in any fastener technical publication anywhere to Machinery's Handbook. It is not an authority on the subject and is frequently representative of out of date information. I am willing to clean this up if it isn't going to be changed right back to inferior references like the Machinery's Handbook. (chwillia1) — Preceding unsigned comment added by Chwillia1 ( talk • contribs) 21:56, 28 November 2012 (UTC)
In general, I oppose the removal of material solely because it is "obvious" -- see WP:OBVIOUS. I also even more strongly oppose deleting references to relevant standards organizations because of writing issues such as "The wording might be improved" or "It fails to provide a lead in". Such writing issues are relatively easy to fix once the information is in the article. All too many Wikipedia articles lack good references -- which seems to indicate that a lack of references is relatively difficult to fix. -- DavidCary ( talk) 01:56, 21 July 2013 (UTC)
I came here looking for a Woodscrew Size Conversion Chart, between metric and screw number sizes. Please can anyone add a chart or a link to one ? Many thanks ! Darkman101 ( talk) 19:32, 7 August 2013 (UTC)
I think the order of sections in this article is a bit odd. I would have expected history to be first, followed by types of screws. It seems strange to me to have "differentiation of screws and bolts" as the first section. I don't think the majority of people come to this page looking to learn about the differences between screws and bolts; I'd imagine that history of screws and screw types are the most frequently sought after sections. — Preceding unsigned comment added by Blelbach ( talk • contribs) 05:34, 19 October 2013 (UTC)
I am finding this page confusing or at least not confidence-inspiring because differences between various national or international standards are not made clear. For example, wood screw gauge is a number in the US and the UK. But is it the same number? Are US inches even the same as UK inches? The page doesn't say, and it refers to gauges without saying which system they come from. Hence, my lack of confidence in the information in this page ... yes, yes, I should add this info myself. But it's not my area of competence, which is why I came here in the first place. 87.113.51.124 ( talk) 10:29, 18 March 2014 (UTC)
What does everyone think of converting the types of screws section into a table format, like the one at wrench, so that images can be included with the descriptions? I think its a cleaner layout as well. Wizard191 ( talk) 16:05, 31 December 2010 (UTC)
The definitions under Cap Screw are incorrect (albeit very minor): "A socket cap screw, also known as a socket head capscrew, socket screw, "set screw" or Allen bolt, is a type of cap screw with a cylindrical head and hexagonal drive hole."
We are choosing some screws for metal door use, and would like to find the mark's means. Thanks in advance. — Preceding unsigned comment added by 183.26.40.117 ( talk) 01:06, 7 December 2013 (UTC)
73.185.194.135, you're mixing some things together in your mind, some of which are true trends and some of which are scary extrapolations of those trends into frightful ghosts. To start, you're conflating (1) the total variety of what existed on earth 40 years ago versus (2) which subset of it that you saw at that time, based on the particular books and periodicals you were looking at (a subset of what existed). You say "The H for head was never used", and yet I just showed you scanned copies, scanned directly from printed books and magazines from 1910 and from 1970, of people using it. Your idea that "it didn't exist at that time" is wrong, which is verified using printed books and magazines from that time (despite your fear that all such printed works are equally lost). Please understand that I'm not picking on you, either. I am just duly defending the valid info that is collected here and pointing out the aspects of what you're crusading about that are misextrapolated. You should breathe easier knowing that the misinformation that the ignorant kids share online today is often more falsifiable than your fears suggest. The stuff that's wrong (as in counterfactual) is quite often exposed sooner or later. As for what's "wrong" as in "things people do that you wish they didn't"—rest assured that that's been going on since long before the internet. It is certain that many American machinists and hardware dealers were using 'H' for 'head' in the 20th century (which the 1910 book gives evidence of, and which I encountered personally in the 1990s). This article covers the terms that machinists and hardware dealers use just as much as it covers the recommended nomenclature of engineering societies. You've taken a legitimate general concern about how experts interact with amateurs since the advent of the Web (these damn kids mostly don't even look at printed works anymore) and extrapolated it in your mind into a bit more of a monster than it is (fortunately, there are [literally] millions of printed works at everyone's fingertips at http://books.google.com/advanced_book_search and https://books.google.com/ngrams/—people may not get engineering books out of the library much these days, but OCRd scans of millions of those books are available online for falsifying wrong ideas). Nothing in this article contradicts reality, either of today or decades past. If there's a piece of reality missing, feel free to add it. But your idea "The H for head was never used 40 years ago" isn't reality. It would have to be modified to "no standardized engineering nomenclature used 'H' for 'head' 40 years ago" in order to be a piece of reality. And you could probably point to multiple MIL standards, ASTM standards, SAE standards, and British Standards that don't use the 'H' in their nomenclature. As for the idea that "standards don't exist anymore", that's actually completely wrong—there are a shitload of standards that manufacturers currently have to comply with (ASTM, SAE, NAS/AS/AIA, the many active MIL standards, ISO, FDA, and many others). The boobs chatting on Yahoo aren't consulting them, but people in the manufacturing industries are damn sure consulting them every day, at sites like this, where they pay through the wazoo for copyright-protected PDFs of them (although a lot of sharing of copies on the down-low happens, too). Your idea (paraphrased) that "nothing that was printed back then is ever looked at now" is a misextrapolation; although that is often true, the links above are some of the instances when it is not. You may have a belief that "the best engineers didn't use the H", but that is different from "it didn't exist." Regarding "We have no rockets to fly to space because standards are lost and the ability to produce such a rocket is gone"—Although it is well publicized that a lot of institutional memory from the Saturn V era is lost thanks to people getting older and passing away, paper files being discarded or crumbling away, the damn kids and their video games, and so on, the idea that the news media drums into our heads—about some planet of the apes type of loss of technology—is something that they do on purpose to rile people up into a worried, angry froth. Much of it is clickbait, but some of the people churning it out believe it, too, because many of them have little accurate understanding of the topic. Here is a news story closer to the truth of what is happening in terms of future space tech. It's not all just a bunch of apes clambering over the half-buried Statue of Liberty. To sum up, don't let the media scare you into believing an evil-clown caricature of what really is happening. Yes, good information gets lost or siloed. But the aerospace, defense, and medical device industries are still cranking out high-tech stuff. And if the people who hold the purse strings ever decide to build a new Saturn-type rocket, you better believe that Boeing and Lockheed and their legions of suppliers will reinvent one that works, for enough billions of dollars. Of course, we'd better tend to the economic underpinning of that, though, if we want any billions to exist. So squashing the middle class (and thus cratering our economy) is not in the MIC's own interests, and hopefully they will realize it eventually. — ¾-10 23:22, 26 August 2014 (UTC)
This article currently defines "shank" with a good reference. Great!
Unfortunately, this article currently uses "shaft" a few times without illustrating or defining the term.
I was on the verge of editing the article to say that "shaft" and "shank" are synonyms, as a result of the above " #What does shank mean?" discussion.
But then I came across one website [1] that seems to say that (paraphrasing): The shaft is the smooth, unthreaded section from the underside of the head to the start of the threaded section. The shaft is only a small part of the shank.
Can we get reliable sources defining "shaft"? -- DavidCary ( talk) 00:13, 13 February 2015 (UTC)
Is a worm screw another name for a set screw (aka a grub screw)? Should it be added? — Preceding unsigned comment added by 81.107.32.7 ( talk) 07:47, 17 February 2015 (UTC)
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From the opening section:
Some screws have an unthreaded portion of the shaft under the head, which is known as the shank.
In every other place the word shank is use it sounds like it means shaft. For instance:
Fasteners with a non-tapered shank are designed to mate with a nut or to be driven into a tapped hole.
The word shaft was replaced with the word shank throughout the article. That seemed to make sense if shank means shaft with regards to screws. Shank seems like a more specialized fastener type word. But if shank actually means the unthreaded part of the shaft then consideration might be given to modifying at least some of the sentences that use it to mean the whole shaft.
The nail article defines shank as:
the body the length of the nail between the head and the point; may be smooth, or may have rings or spirals for greater holding power
It seems like shank=shaft when it comes to screws. I would like to have confirmed that with a dictionary definition but the definitions I saw didn't cover this issue, at least not unambiguously. What is the source for the definition of shank provided in the opening paragraph? -- Davefoc ( talk) 10:19, 18 September 2009 (UTC)
D. Shank-the cylindrical part of a bolt that extends from the underside of the head to the point.
I cannot recall ever seeing 'shaft' used in this manner; 'shank' is the right term. —Preceding unsigned comment added by 72.72.20.207 ( talk) 17:43, 20 January 2010 (UTC)
From ISO 1891 Fasteners -- Terminology, it is clear that shank is the unthreaded part. It is synonymous with 'body'. Other reference: https://www.boltdepot.com/fastener-information/terminology.aspx — Preceding unsigned comment added by 84.196.104.49 ( talk) 14:41, 19 April 2015 (UTC)
A new editor, Glooop, made the following addition to the introduction, but not in the right place. Perhaps it can be worked into a scientific description:
Amandajm ( talk) 06:02, 31 March 2012 (UTC)
No, its not. this more closely defines a screw thread but not a screw. — Preceding unsigned comment added by 205.243.112.221 ( talk) 21:11, 28 November 2012 (UTC)
"A screw in its most general form is one of the Simple machines of Renaissance times, and when used as a fastener the concept of an inclined plane explains how relatively little force/ torque applied to a screwdriver may provide a fastening capable of withstanding high [[Stress (mechanics)|stresses]"
I also think it would be helpful to include some wording around this point to explain screws may have uniform (diameter & pitch) threads (e.g. grub screws) or have tapered threads (e.g. wood screws). Maitchy ( talk) 01:01, 9 February 2016 (UTC)
When was the wood screw developed? The nut-and-bolt? When did they become cheap enough for common use? Paul, in Saudi ( talk) 14:18, 1 November 2013 (UTC)
Actually the assertion that wood screw wer quite ancient is unsupported. The cited source states that screws as fasteners were first developed in Europe in the 15th century. The history section contains some imaginative misrepresentation of that cited source. 184.45.21.70 ( talk) 16:47, 25 March 2016 (UTC)
This article says that coach screw and coach bolt are synonymous but different from a carriage bolt and is in conflict with Carriage bolt where a carriage or coach bolt are synonymous and are retained by a nut as opposed to a coach screw. As I suggest it should be. Cinderella157 ( talk) 06:13, 31 January 2017 (UTC)