Talk:Screw/Archive 2

Expired patents

Patents are only valid for at most 20 years (normally 17 years for design patents in the US, 20 years in the UK), so I've removed a few statements that implied that the Pozidriv is still covered by a patent. The name itself is a trademark, and trademarks can be protected and licensed indefinitely, but the design of the screw is only protected for a limited time, and for designs that date at least from the 1960s, the patents are long gone (which means that anyone can make and use the screws, as long as he doesn't call them Pozidriv). Trifast or GBK or whoever may still license trademarks for use with these screws, but they can't license patents that have expired. Citations needed if patents are mentioned, I think. Agateller (talk) 13:37, 8 March 2009 (UTC)

Threaded inserts

Under the Other fastening methods section there's a sentence about threaded inserts as another fastening method. I don't think that threaded inserts are applicable because the inserts, in and of themselves, don't fasten two objects together; they just allow a screw/bolt to attach to something that it normally wouldn't be able to (for instance: plastic). I think that the sentence about threaded inserts should be removed and a link to threaded inserts added to the see also section. --Wizard191 (talk) 14:12, 12 March 2008 (UTC)

Done. Wizard191 (talk) 13:59, 22 November 2008 (UTC)

Robertson vs. square drive

I recommend the text below be modified. Based on examinations of modern square drive screws and screwdrivers made in and for the United States' market the description of the square-drive head is not accurate.

1. Robertson head, invented in 1908 by P.L. Robertson, has a square hole and is driven by a special power-tool bit or screwdriver. The screw is designed to maximize torque transferred from the driver, and will not slip, or cam out. It is possible to hold a Robertson screw on a driver bit horizontally or even pendant, due to a slight wedge fit. Commonly found in Canada in carpentry and woodworking applications and in Canadian-manufactured electrical wiring items such as receptacles and switch boxes.
2. Square-drive head is an American clone of the Robertson that has a square hole without taper. Due to the lack of taper, the hole must be oversize relative to the screwdriver, and is much more likely to strip than the Robertson.

I suggest the text as follows: Robertson head, invented in 1908 by P.L. Robertson, has a square hole and is driven by a special power-tool bit or screwdriver. In the United States it is referred to as Square Drive. The screw is designed to maximize torque transferred from the driver, and will not slip, or cam out. It is possible to hold a Robertson screw on a driver bit horizontally or even pendant, due to a slight wedge fit. Commonly found in Canada in carpentry and woodworking applications and in Canadian-manufactured electrical wiring items such as receptacles and switch boxes. It is increasingly used in the United States for woodworking applications. Square-drive head is an American clone of the Robertson that has a square hole without taper. Due to the lack of taper, the hole must be oversize relative to the screwdriver, and is much more likely to strip than the Robertson.

This 2007 talk supports the same argument:

The information about Robertson being different from 'American' square drive in terms of its taper is totally false. This shows up from time to time in woodworking magazines, and I looked into it by speaking by phone with James Ray, owner of McFeely's Square Drive Screws in Virginia (www.mcfeelys.com). He told me that the reason the screws are called square drive in the US is the trademark issue and licensing fees over the use of the name many years ago. Robertson is said to be viewed as something of a Thomas Edison in Canada, and I get the impression from several letters to the editor that I have read over the years is that the Canadians and others have used this issue to express their anti-Americanism. I saw one such letter in a British woodworking magazine by a man who had lived in Canada for a period. He was extolling the virtues of the screw, and then went on a rant about how they are called square drive in the US because Americans don't want to acknowledge anything that didn't come from the US.

The Robertson name is used here and there in the US for either the fasteners or the bits that drive them, though square or square drive is more common because of the history of the name mentioned above. —The preceding unsigned comment was added by 68.160.185.160 (talk) 14:03:26, August 19, 2007 (UTC)

Thank you, SchreiberBike--SchreiberBike (talk) 04:20, 16 July 2008 (UTC)

Changes made as proposed above without objection. Thank you, SchreiberBike SchreiberBike (talk) 04:37, 20 August 2008 (UTC)

Socket Head Cap Screws

"Because of higher stress from the small head diameter, socket screws are best used with a washer when possible."

If one examines the underside of a hex capscrew's head, one will see the same diameter bearing area as on a socket screw of the same size. The above statement is incorrect.

Bigdumbdinosaur (talk) 19:05, 19 September 2008 (UTC)

Bolt screw, Differentiation

I don't want to make things more complicated, but I'd like to re-open this discussion I'm not satisfied as to how it now stands regarding the differentiation of bolts and screws. I'm restraining myself to a few {{fact}} tags for now. It does seem to me that a more meaningful definition would be that usually screws are self taping, and bolts thread into a pre-threaded thing, nut or otherwise. Importantly and, adding much confusion, not all subclasses of screws and bolts conform to this naming convention. As such a "Lag Bolt" is in fact a type of screw. [[1]] agrees. I don't know where or how size plays into it. Oxford Advanced Learners Dictionary (It's close at hand) defines screw as "a thin pointed piece of metal like a nail with a raised SPIRAL line (called a THREAD) along it and a line or cross cut into its head. Screws are turned and pressed into wood, metal, etc. with a SCREWDRIVER in order to fasten two things together." And Bolt as "a piece of metal like a screw without a point which is used with a circular piece of metal (= a NUT) to fasten things together". While these are simple and don't entirely prove my point they point in the same direction as me. --Keithonearth (talk) 05:18, 21 November 2008 (UTC)

Your thinking is entirely valid. I would only add that there is no resolution at the end of the rainbow by trying to reason through it, because the reason that the usage is inconsistent has to do with the nature of natural language and of the history of technology (which necessarily spurs changes to nomenclature, e.g., through retronymy). The only way for there to be a clear, consistent differentiation between the meanings of the words "bolt" and "screw" is for that differentiation to be defined and enforced via legislation, regulation, or standardization—i.e., via some form of controlled vocabulary. It can't exist as a feature of wild language, because that's not how wild language works. Any fastener with screw threads on it will end up being called a "screw" by some percentage of laypeople, regardless of a distinction about whether the threads engage the substrate or pass through it via a clearance hole to engage a nut on the other side. I think that the reason why this topic exasperates so many people is that they're looking for something that isn't there, which is a unitary mechanism of control that would be governing natural language vocabulary. Some mechanism that involves systems engineering, memos from God, irreducible objective logic, or some combination of those. In the case of some languages (e.g., French, Spanish), there are organizations that have some claim to authority of being that mechanism that controls the vocabulary and orthography, although their control has its epistemological and practical limitations (Académie française, Real Academia Española). In the case of the English language, there isn't any such mechanism. But we grow up thinking that there must be. You can detect this flawed epistemology when people talk about consulting "the" dictionary—as if there is only one; as if that "one" has ultimate answers that resolve traceably back to the very fabric of space-time; as if "a" dictionary isn't just one group's idea of how English does work or should work. So the epistemology of language is fundamental to this topic, but it's a level of abstraction that many people are unfamiliar with. The other thing going on is the relationship of nomenclature and retronymy to the changing of technology over time. Rod-shaped fasteners that (a) passed through clearance holes in the substrate to be fastened on the other side in some way (clinching, swaging, forge welding, cotter-pinning, wedging, etc), and (b) were called bolts, (c) were in use since many centuries before screw threads were practical and affordable for widespread use on fasteners. I.e., centuries before the slide-rest-and-leadscrew-equipped screw-cutting lathe and centuries before the screw machine. What concept unites the many senses of the word bolt in English? At heart, it is the concept of a rod—a thin cylinder. And that is the only irreducible heart of the word's meaning. In the 19th century there was an era during which people would say "screw bolt" referring to a bolt whose end fastening was via screw threads. This stood in contradistinction to a term such as "clinch bolt", whose end fastening was via clinching. Since then threaded fasteners have become so ubiquitous that "screw bolt" sounds redundant. It made perfect sense back then, in that context, at that moment in the history of technology. Today, I think it's all well and good to try to marshal the mob into following the rules of a controlled vocabulary whereby you consistently use one word to refer to one object type (a fastener that passes through the substrate via clearance hole to be fastened on the other side) and another, different word to refer to another object type (a fastener that threads directly into the substrate). But we all need to understand that currently in natural language there are conventional exceptions to that rule (e.g., "cylinder head bolt", "lag bolt"), and that the only authority that exists to change that fact is the authority of style guides, the authority of standards organizations (e.g., DIN, ANSI, ISO), the authority of dictionaries (note well the plural), the authority of lawyers, legislatures, and judges. Memos from God are not involved; the exact linkages between the daughters of earth and the sons of heaven are based on local-context logic that gets defied by context scaling. We all need to understand that natural language evolves in response to technological change. We all need to understand that natural language evolves in multiple localized contexts (geographical, temporal, historical, technological) and that universal context and/or context-independence are not features of natural language. That's why, as the article currently says, "A universally accepted distinction between a screw and a bolt does not exist." — ¾-10 20:21, 22 November 2008 (UTC)

Thank you for your well thought out and extremely thorough response. While I agree with you overall, I do think that the current wording of the article over emphasizes the ambiguity, and is not as useful as it could be. Just because ultimately there is no absolute definition of "bolt" or "screw", that doesn't mean we can't get a better one than we have now. After all the same argument could be extended to any word, and yet we are still able to communicate. I can go into a hardware store and ask for a bolt or a screw and they will know what I mean. I don't think the "A universally accepted distinction between a screw and a bolt does not exist" line needs to be removed, but I do think the differentiation should be made more clear. Particularly confusing for me is that size is mentioned before self-taping/not-self-taping as a defining characteristic. I'm not sure but this seems to be an attempt to find a pattern in the use of screw/bolt in the names of the subclasses, as such is not useful (if it is that could make it OR, but anyways has no reference). Thanks again.--Keithonearth (talk) 22:40, 23 November 2008 (UTC)

I've added a few references, and attempted to clarify things a bit. If no citations are added for size as being a defining characteristic of screws/bolts I'm going to remove the statements as I can't find any backing for it, nor does it correspond with my experience.--Keithonearth (talk) 08:35, 4 December 2008 (UTC)

Hi Keithonearth and Three-quarter-ten, I thoroughly enjoyed the discussion above. I found the information about the early use of the term screw bolt very interesting. As the originator of the "A universally accepted distinction between a screw and a bolt does not exist." line I was happy to see that it stayed. But I was equally happy to see the excellent changes that were made to the overall section. I had contemplated doing some work to add some references but I'm glad I didn't after I saw what a nice job Keithonearth did on updating the section. A small comment on the issue of size and whether it is part of the definition of screw: From my point of view it absolutely is. Have you ever heard of a watch bolt? And yet almost all watch screws are designed to mate with a tapped hole. In general usage most people don't call small threaded fastening devices "bolts". Some people would like to change that because the terms screw and bolt are ambiguous and don't quite make sense as they are generally used. Unfortunately for the people that would like to formalize the word "bolt" to mean a threaded fastener designed to mate with a tapped hole, other people have formalized a definition of machine screw which conflicts with that. Davefoc (talk) 10:04, 5 January 2009 (UTC)

I had a few thoughts since I read this discussion last night. 1. Lug bolts is another very common term for a threaded fastener designed to mate with a tapped hole instead of a nut. Its function is very similar to what a watch screw does. The main distinction between the two is that lug bolts are big and watch screws are small. Similarly the threaded fasteners that hold the vessel together that houses a large steam turbine are going to be called bolts by the people working with them. The thought to call them screws because they are not intended to mate with a nut probably doesn't occur to anybody working on it. In popular usage screws are small and bolts are big.

2. Three-quarter-ten's comments about the early use of the terms bolt and screw are interesting enough that it might be nice if they made it into the main article someplace. It seems like the seeds of ambiguity for the two terms were planted early. I had never realized that the term bolt was applied to an unthreaded fastener that probably would be called a rivet today.

3. It might be nice to add the term "lug bolt" to the list of bolt types. Davefoc (talk) 20:31, 5 January 2009 (UTC)

Hi Davefoc! Glad you found the discussion interesting. I remember all the work you did on improving the article a while back. Re-reading my comments, they seem to sound a little cranky, but rest assured everyone that I was not "cranking," just wrestling with a hard-to-explain topic. I think Keithonearth has done a great job as well. I agree completely with Davefoc that there is a mostly unspoken force behind the natural-language usage that can be explicitly spoken as "bolts are big, screws are small." I think the main reason we call cylinder head bolts "bolts" is that "they're too big to call screws." Of course, it's more of a connotation thing than a denotation thing. And of course, it has nothing to do with the logic of the official controlled vocabulary (ANSI, ISO, etc). Nevertheless I do agree that it is a fact of the natural-language usage. I think there must be a succinct way to say this in the article. Maybe one of us will get time to incorporate it soon. To all, happy new year. — ¾-10 03:15, 6 January 2009 (UTC)

I have reread the differentiation article. I did not realize that all reference to size with respect to the use of the words, "screw" and "bolt" had been removed. This is just wrong unless Wikipedia is designed to represent what somebody would like rather than what is. Even in the article there is a picture of a "Combination flanged-hex/Phillips-head screw used in computers" that is designed to mate with a tapped hole. Although for the most part, Keithonearth's edits made the section more clear and better documented as it stands now the article fails to identify what is either the most common or the second most common differentiation in most English speaker's minds about what is a screw and what is a bolt. Is there anyplace that the threaded fastener in the image I referenced would be called a bolt as standard practice? I'm not aware of that place if it exists. Has anybody gone into a hardware store lately and found where they stock the 6-32 bolts? Davefoc (talk) 04:48, 6 January 2009 (UTC)

I certainly wouldn't put up something that I didn't feel to be true, out of wishful thinking, or any other reasons. I honestly have never heard sized used as a determining factor, or read it in print. I think it's really important to be careful about objectifying one's opinions, and it seems to me we are disagreeing about what is, not what either of us want to be. It also seems my interpretation of the facts was dismissed by suggesting that it's wishful thinking. I sure wouldn't accuse either of you of wanting small treadled fasteners to be screws. (as silly as that sounds) I also think it is important to differentiate between connotation, and definition. I don't know if that means not including it as a determining characteristic or mentioning it as a connotation. Of course if there's some reference I'd have no choice to accept it.

That said it is hard to know what's right, because there are lots of people who use words in ambiguous ways, or non-conventional ways. For example some people will say tire when the mean wheel. That's non-conventional enough to be conventionally considered "wrong". When is it non-conventional and when is it a variant meaning? There is no absolute way to draw the line, I know, but I still think that doesn't mean we shouldn't try to differentiate things from each other.

Oh, by the way when I took out size as a determining characteristic I did document it in the summery field as I wanted it to be clear what I was doing. And I hope I'm not sounding confrontational here, I'm just doing my best to sort this out too.

It's kind of funny that I use the expression "nuts and bolts" pretty often to mean, very concreate non-abstract things. Now I'm getting into a debate that's pretty abstract about bolts and screws. Maybe I should start saying "threaded fastener and bolts" --Keithonearth (talk) 05:59, 6 January 2009 (UTC)

Thank you for your response Keithonearth,

1. Results of the review of the first two pages of a google search of 6-32 screws (474,000 hits)
7 hits where the use of screw without a modifier referred to a fastener with threads designed to mate with a nut or tapped hole
5 hits where the term "machine screw" referred to a fastener with threads designed to mate with a nut or tapped hole
1 hit where the term "cap screw" referred to a fastener with an allen head type drive that was designed to mate with a nut or tapped hole

2. Results of the review of the first two pages of a google search of 6-32 bolts (162,000 hits)
3 hits where the use of bolt referred to a fastener with threads designed to mate with a nut or tapped hole
This is three more than I expected. In my experience, small threaded fasteners with machine type threads are either referred to as "screws", "machine screws" or on occasion "cap screws" where the fastener has an allen head.

3. Wikipedia not only has the picture of a threaded fastener in this article where the caption refers to a device with machine screw threads as a "screw", this article appears in Wikipedia: http://en.wikipedia.org/wiki/Computer_case_screws. The computer case screws the article is about have machine screw threads.

4. When was the last time somebody bought a "bolt" to repair their eyeglasses with? How many places on the web are selling "watch bolts"?

FWIW, I would be fine with terminology where the terms, "bolt" and "screw" were mutually exclusive. But they aren't in standard usage. Common usage often follows the idea that screws are small and bolts are big. Standard bodies have added confusion to the issue with terms like "machine screws", "lag bolts" and "cap screws". I think your revisions of the screw/bolt differentiation section ignores the reality of the way most English speakers use the terms. While I think you might have a case for this approach if there was a widespread standard that had been adopted by the fastener industry or fastener engineers for appropriate usage of the terms that doesn't seem to be the case. What is the case is that various groups or individuals get an idea of what should be and promote that idea with a standard or an article. But so far the natural language (to use your term) hasn't responded. And maybe reasonably so, when a standards body tries to push a questionable idea like that a bolt changes to a screw when it is used in a tapped hole. Davefoc (talk) 16:33, 6 January 2009 (UTC)

Summery of my points so far:

Definitions:

• Bolt: a threaded fastener that threads into a pre-threaded materrial, e.g. a nut.
• Screw: a threaded fastener that self taps, usually has a tapered shaft

Important detail: sub-classes of screws and bolts do not follow this rule. i.e. machine screw is a sub-class of bolt, "computer case screw" is a sub-class of bolt.

Size:not a determining characteristic of the terms "bolt" or "Screw" in the unmodified sense. A pattern of the use of the terms screw/bolt relating to size may be evedent in the names of the sub-classes, this does not reflect on the use of the words unmodified.

I'm not denying that this is a messy system, or saying the terms are allways mutually exclusive, and particular examples do exist that are not clear as to what category they fit in. There are also other confusing things about the terminology (one "screws" both screw and bolts) But it it is the best system we got. And it's far better than saying there's no difference.

Thank you for your answer too, but it seems like a good part of your argument is based on the fact that the sub-classes are so confusingly labled. It would be easier if machine screws were called bolts because they are little bolts, but that's the messiness of natural language. (Or how I see natural language in this case)

I don't think 7 hits on google where the use of screw without a modifier referred to a fastener with threads designed to mate with a nut or tapped hole counts as a reference, of course one of them individually may, if it's good enough to be used as one. —Preceding unsigned comment added by Keithonearth (talk • contribs) 19:31, 6 January 2009 (UTC)

I realize I'm sort of jumping in the middle here, but I'm not following your logic whatsoever Keithonearth. You are defining "screw" and "bolt" per what you believe they mean and then going on to say that, well specific examples don't fit into this system. Then you go on to say that despite the fact that they don't fit into your system, they also aren't defined by the "size is a relevant characteristic" system. However, Davefoc has shown that that's exactly why those specific types don't fit into your system.

Personally, I like how its laid out right now: a screw can be defined either by its size or by what it mates with. I don't see why that's so bad, because that's exactly how it works in the real world. We are here trying to explain the real world (with the aid of references), not push original research. Per the refs in the article right now, both of these definition systems are documented. Wizard191 (talk) 20:04, 6 January 2009 (UTC)

Hi to all, Comments on Three-quarter-ten's recent edits: For the most party I liked them but I quibble with this line: "Although this connotative linguistic force is not at all incorporated into the prevailing controlled vocabularies, it does explain why in natural usage machine screws are so often not called bolts even when they are used in clearance-hole applications and secured with nuts" I believe the term "machine screw" is actually incorporated into the relevant ASTM specification and I think that machine screw sizes up to .25 inches are defined. ASTM compliant machine screws, I believe, are threaded all the way to the head.

Comment on Wizard191's and Keithonearth's prior comment I think I understand what Keithonearth's point is a bit. The idea is that anytime the word screw is used to denote a fastener designed to mate with a nut or tapped hole it is combined with some kind of modifier. There is something to that because terms like machine screw, cap screw, set screw, and perhaps even watch screw don't perforce mean that fastener specified is a screw. However, I think he is failing to recognize that the term screw is often used as part of a term that is made up on the spot to denote a small threaded fastener. For instance eye glass screw, model airplane screw, etc. People don't use the word bolt in these contexts because in people's mind is the idea that bolts are big and the fasteners they are talking about are small. The second thing he is missing, I think, is that the wide spread stand alone usage of the word "screw" to denote either type of small fastener is evidence that standard English does not abide by the distinction between bolts and screws that he favors. I would be glad to provide him with links to the seven sites that I looked at that used the term exactly like that. For some reason, he doesn't think that those seven sites are relevant to the issue. I don't understand that since we are discussing the definition of a word and how the word is used is exactly the kind of information that dictionary writers look at when deciding on the definition of a word. The last problem that I have with Keithonearth's view is that I don't know what standard body's are promoting his definition. I think I know what the ASTM standard has to say on this and it isn't the definition favored by Keithonearth. So what is the authority for his view?

FWIW, I think the distinction that Keithonearth favors is the most rational one as to what the distinction should be and I'd vote for it to replace the current usage of the terms. But that isn't going to happen in my lifetime and it may never happen. Davefoc (talk) 03:59, 7 January 2009 (UTC)

While with good intentions, I don't think that the last edits done by Three-quarter-ten reflected the consensus. Maybe we are dealing with national differences (me:canada), or maybe I'm just thinking of how trades-men (I tried to type trades-person, but it just didn't happen) would define (as have the couple I work with do when I asked).--Keithonearth (talk) 08:44, 8 January 2009 (UTC)

Hi Keithonearth, I was afraid that my comments might have been on the excessively strident side and I apologize for that. As to your last comment: Perhaps there is a regional difference. When I updated this section earlier, I came across at least one site that made the distinction between bolts and screws that you have advocated for. It would make sense to have words that unambiguously identified the main two types of threaded fasteners. But I don't think that is the way the language or the standards that I am aware of evolved. Most of the standards went in the direction of making things more confusing IMHO. A cap screw is a threaded fastener with a tighter tolerance than a bolt according to the ASTM standard. Or the old distinction that a cap screw was a bolt with threads all the way to the head. Or the nonsense about how a bolt can turn into a screw depending on the intended usage. I can see a historical path sort of that led to some of this, but unfortunately today it just adds to the confusion. The most important point is that the terms bolt and screw are ambiguous. And the natural language usage seems to have dealt with that by establishing two or three word terms that fairly unambiguously describe a particular fastener. e.g. dry wall screw, machine screw, head bolt, lag bolt, etc.Davefoc (talk) 18:56, 8 January 2009 (UTC)

I don't think you were excessively strident, but thanks for the apology. I'm sure you are just trying to make the article better, we just disagree on how. While I don't think that there's a need to expunge size reference entirely, I think it is receiving too much emphasis now, as it's something I've never heard of before. I'm a bicycle mechanic and we allways say "bolt" for the 5mm bolts that are common on bicycles. As we do for the 4mm, 3mm, and smaller that are less common. Second I recognize that there's no solid line, but think that shouldn't mean we say there's no line. Both in the case of division between bolt/screw, and between who is using the terms (for lack of a better term) "correctly" and who is using the terms "incorrectly". Nothing hard and fast here, nothing absolute, maybe "helpfully" "unhelpfully" would be a better ways to say it, but you get the idea. A comparison: My mom uses the term "download" to refer to putting files onto/taking off a USB drive, burning to cd, copying from cd, and in all sorts of other ways. And it's not just my mom who uses the term in this flexable way. The download article doesn't say anything about this usage, nor need it. We all know people do this, but more computer literate people perfer a definition that makes more sense, ie is more helpful. It seems to me that's how words in a natural language develop meaning. So: Size as a determining factor, never heard of it; screw used for things that go into a nut, sure I've heard it said, by people who don't know better, ie people who don't work in a trade, people who are not mechanically knowledgeable. --Keithonearth (talk) 18:34, 9 January 2009 (UTC)

Keithonearth, have you read the first reference in the section? It is from the Machinery's handbook edition 25. I have looked at what edition 23 and edition 26 have to say and I assume that they say what is in edition 25. Here is a quote from edition 26 Page 1492:

Differentiation between Bolt and Screw. - A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut.

A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread of being tightened or released by torquing the head.

An externally threaded fastener which is prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bot. (Example: round head bolts, track bolts, plow bolts.)

An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw. (Example: wood screws, tapping screws.)

This differentiation is the only one that is based on a formal specification that I am aware of. The one that you are advocating is one that is advocated by some people possibly because they are looking to create two unambiguous terms to unambiguously identify the main two types of threaded fasteners. This is a reasonable goal. There are two problems with it: It is neither compliant with formal specification nor standard usage. It would be reasonable for this article to make mention of it as there does seem to be some support for the idea. But it is not compliant with standard US English where small threaded fasteners are very rarely referred to as bolts in standard usage nor is it compliant with any formalized specifications that I am aware of. One last note: This situation is made even more confusing because "cap screws" and "bolts" have very similar specifications and can be used interchangeably. So is a cap screw a screw or a bolt? Probably a cap screw is a bolt. The Machinery's handbook refers to the parenthetically as "Finished Hex Bolts". And to add a little more confusion the term cap screw is sometimes used to describe what is formally identified as a "hexagon socket head cap screw" which is most commonly known as an allen head screw.

One last thing I would like to note: With the differentiation method described in the Machinery's handbook, things like watch screws are screws not because they are small but rather because they are designed to be screwed into a tapped hole that is part of the watch. The MH differentiation runs into conflict with common terms like lug bolt and head bolt and it runs into confusion with things like machine screws which are often used with nuts and which are often screwed into a tapped hole or an insert that is part of an assembly.

I would like to try to rewrite this section to incorporate what I believe the situation and the partial consensus is about this issue and post the rewrite here for review. Davefoc (talk) 08:06, 10 January 2009 (UTC)

davefoc's proposed bolt/screw section update

I have updated the differentiation with the update below. I realize that what I did might not have been completely consistent with what everybody wanted. I hope I captured enough of the consensus and the relevant facts that people are at least ok with what I did.

Although I was a little annoyed when "citation required" popped up all over the differentiation section that I was largely responsible for, the fact is that I allowed my ideas about what the situation was to unduly influence me. I didn't do adequate research to validate my ideas. It really wasn't until I was discussing the issues with Keithonearth that I came to realize that the general thrust of the original article was wrong. The fact is that there is something of a standard out there for what the words, screw and bolt mean and that is what the article needed to emphasize the most.

That the standard does not provide an unambiguous answer to the issue of what is a screw and what is a bolt and that common usage are somewhat at variance with the standard are secondary issues which are now discussed more appropriately farther down in the piece.

I think 3/4-10's historical insights bring home the idea that the terms are ambiguous and that's just what happens sometimes when technology changes in ways that make it so that older terminology doesn't fit the new technology as unambiguously as we might like. The various readings that I did on this subject made me more aware of how some of this terminology came to be and why it just isn't as neat as we might like. I was tempted to throw a little bit more of that into the article than I did. I felt that the section was already nearing overlong if it wasn't there already and I tried to constrain myself.

I'm going to erase the first cut at the new section from the talk pages tomorrow if nobody objects.

And of course, there's the possibility that somebody really objects to what I did in which case perhaps a revert is in order.

Open stuff: There is still some additional references that might be added. I think the idea that the ambiguity of exactly what is a screw and what is a bolt is not a problem because where there is the potential for ambiguity people just use a more specific term possibly should be put back into the article some place. I tried to get a better feel for how other countries use the term screw and bolt, but I didn't find significant information on it. I did find a mention of the fact that the term, cap screw, in Britain in still used to refer to a fastener with threads up to the head. Please feel free to whack away if you think I've made mistakes.

Best Regards, Dave

Davefoc (talk) 02:25, 15 January 2009 (UTC)

3/4 -10 made an edit to the discussion version of the section as follows: The word screw is a very old word whose [davefoc had previously replaced whose with that's] basic meaning has long involved the idea of a helical screw thread.

Clearly davefoc's use of the word that's was wrong. My apologies. whose was correct. However, I changed the sentence in the actual article to this: The basic meaning of the word screw has long involved the idea of a helical screw thread.

Please feel free to change this again if you feel my change to your sentence wasn't correct.

I am going to eliminate the discussion section copy of the article now to eliminate the possibility of edits going on in two places.

Davefoc (talk) 04:30, 15 January 2009 (UTC)

notes

Some relevant web sites on the issue http://www.sizes.com/tools/bolts.htm
http://www.tpub.com/content/logistics/53/06/425/01-527-9849.htm
http://www.fcsuper.com/swblog/?p=104
http://www.boltscience.com/pages/faq.htm#14
http://www.ll.georgetown.edu/federal/judicial/fed/opinions/01opinions/01-1006.pdf Court case dealing with the issue of what is a screw and what is a bolt
http://euler9.tripod.com/bolt-database/boltdef.html site advocating keithonearth's view of the difference between a screw and a bolt
http://autorepair.about.com/library/glossary/bldef-900.htm reference for definition of lug bolt
http://www.autozone.com/az/cds/en_us/0900823d/80/04/9d/48/0900823d80049d48/repairInfoPages.htm reference for definition of a head bolt
http://books.google.com/books?id=WqI7AAAAMAAJ&pg=RA1-PA702&lpg=RA1-PA702&dq=sae+uss+screw+standard&source=web&ots=Q80gULeS1u&sig=Yhw1xg4bLK7PCxBP7vpMaEdyLzI&hl=en&sa=X&oi=book_result&resnum=2&ct=result#PRA1-PA701,M1 Reference for early USS and SAE hex bolt and cap screw differentiation
Davefoc (talk) 05:47, 12 January 2009 (UTC)

comments on davefoc's proposed update to the differentiation section

Are you proposing replacing the current text with the above? Or are you proposing something else? Wizard191 (talk) 15:43, 12 January 2009 (UTC)

I propose to replace the current section with this, except that some references would be added to it. Some of the statements are based on the results of web surveys where I tried to determine common usage. I wasn't quite sure how those should be referenced. I also wasn't sure whether to reference the individual who was advocating for the distinction that Keithonearth favored. He doesn't seem to be an authority and his ideas on this are not backed by reference to any standards, but besides keithonearth there was some web usage of the word, bolt, in the way he advocated.

OK. Keep in mind that web search results are not a legitimate source, see WP:GOOGLE. However, you can reference specific sites from the search that use the term in the way that you are advocating. As for that tripod website, I don't think that passes WP:RS because it's self-published without references. Wizard191 (talk) 18:41, 12 January 2009 (UTC)

Hi Wizard191, Thanks for your comments. The difficulty here is that at least some of what this section is about is how the terms are used. A single web site doesn't go to that question very well. What I did was try to review most of the sites that are selling screws and bolts and see how they are using the terms. I wasn't sure how to document that. I could reference a few of these sites and make a note that their terminology is representative. As to the tripod website: It is absolutely not useful as a reference to a particular fact other than that it exists which is what the basis for the reference would be. I intended to reference it and a site selling machine screws where they were referred to as bolts as evidence that keithonearth's idea about the distinction has some usage support.

To Keithonearth and ¾-10 , I very much hope to get your feedback as to what I have done. I am not a particularly sensitive individual and if you disagree with the approach completely I will not be offended. Thank you. Davefoc (talk) 21:15, 12 January 2009 (UTC)

I added some references to the proposed update and made numerous small changes to grammar or syntax. I propose to change the existing section to this one and make additional modifications to it there. There are still some references that I intend to add and I plan to validate the existing references more carefully, but I'd like to do that after the change is made.

A comment on ¾-10's idea about the order and whether the why or the what should go first. I thought the what should go first because this topic is probably already overlong for what the average readers cares about on this subject and the putting the what first allows the reader to get out easily without going thru a lot of verbiage to get to that which he might have been most interested in. I think you suggested something similar and I agree with that. Davefoc (talk) 05:00, 14 January 2009 (UTC)

¾-10's feedback

Nutshell answer: Davefoc's draft is a solid draft, and I am OK with using it, although I think I would want to tweak or augment it, that is, I would see it as a good start that we could still build on in certain ways. Maybe further developing the subsection "Discussion of the historical usage".

Explanation/further discussion: One of the things we need to accomplish here is not just to state that there are conflicting definitions, but to explain why there are conflicting definitions. To my brain, and I believe to some other brains, the why actually is more revealing—answers the question better—than the complicated list of details that are needed to tease out all the ways that the words are used. We could approach it details-first, why-second, or why-first, details-second, but either way, I feel that we should include both parts. To my kind of brain, a why-first, details-second approach is more easily digestible. But I guess for some types of brain, the why part seems digressive, and to lead off with it seems puzzling or irrelevant. Honestly, I think that when people ask this question about the differentiation between the two words' meanings, they are expecting to hear a one-paragraph answer. To my mind, as soon as they find out that it's not that simple, before they digest the long list of usage details, the very next thing they should learn is why it's not that simple. But maybe Davefoc's approach is good in this respect because he simply says up front, "...not completely resolved with Machinery's Handbook distinction, however, because of confounding terms, the ambiguous nature of some parts of the distinction, and usage variations." He gives a very succinct "why" without telling a long boring story. Then, for people who are interested or who can handle it, you would broach the "why" more completely later, under subsection "Discussion of the historical usage", because the thumbnail upfront "why" doesn't justify why people should respect "usage variations" as being epistemologically legitimate. That is, to a prescriptivist, "variant" means "incorrect," but no linguistic scientist—no one who properly understands how languages evolve—agrees with that equation.

Thinking aloud, aka feel free to stop reading at this point: Some mention of the idea of controlled vocabulary versus natural language needs to be kept, regardless of where exactly it segues in. People ask what the differentiation between the two words' meanings is, and you can't properly answer that question without mentioning the simplest basics of the epistemology of language. In other words, talking about the question, "Who decides what words mean?" To put it another way, most of the people who ask this particular question, and most of the people who (failingly) attempt to answer it, aren't even clearly aware of the existence of a difference between linguistic prescriptivism and descriptivism, let alone understanding how the two both influence the answer to the question. Speaking of poor attempts at answering this question, in the U.S. DHS pdf reference, I think it's hilarious reading a lawyer's flawed imagining of what "coarse" and "fine" refer to with respect to screw threads. It just goes to show that sometimes the people answering a question in published form don't actually know the whole story themselves.

Whew! Time for bed! — ¾-10 04:15, 13 January 2009 (UTC)

¾-10, I have reread and reread the section in that pdf that you referenced trying understand exactly what that section meant without success. Unfortunately this blather actually made it into a document that underlied government regulation. That paper seems to have been the basis for the case I linked to. I tried to understand the case a bit, but I might not have understood what was going on exactly. It seemed like there was some international agreement that said if different levies were going to be charged a mutually exclusive distinction between a screw and a bolt needed to exist. The government said that it had one in that paper and the defendant said that it wasn't consistence with normal usage. I would have added that the person who wrote the government's rules didn't understand what he was writing about. Regardless of all that, the defendant lost its case. Side note: Can you believe the government has actually wasted time trying to establish different tariffs on a screw and a bolt?

On your historic usage thought: one thing I came across when I reread the information on the old USS/SAE standards was that at an earlier time hex cap screws and hex bolts were manufactured differently. It sounded like cap screws were entirely machined out of a solid bar and bolts might have been partially forged which was the reason for the tolerance difference. It might have also been behind the idea that cap screws were designed for use in tapped holes and bolts were for use with nuts where looser tolerances might have been acceptable. All this is probably fairly obsolete today where modern manufacturing techniques easily make high tolerance bolts. It is inconvenient that a standards body hasn't moved to provide two terms to unambiguously refer to the two main types of threaded fasteners today, but as a practical matter I don't suppose it matters much since people that work with these things use terms that unambiguously describe what they mean. I doubt that the mechanic that is installing a head bolt ever stops to think or care that the ASME specifies that the head bolt he is installing is really a screw.

I think what I'd like to do is just paste the above section over the old one and work on it there if that was acceptable to you. Alternatively I think there's something like a sandbox around here and if that allowed this kind of thing we could work on it there. Davefoc (talk) 07:24, 13 January 2009 (UTC)

Yes, I would be fine with going live with it and working on it there. Cheers, — ¾-10 02:40, 15 January 2009 (UTC)

Now that the dust has settled, I say, "Good job everyone"

Looking at the settled-dust results of the most recent round of revision to this section, I would like to say that I think it has been an example of successful collaboration where everyone's input ended up being properly incorporated, even though no one person would have produced this end result on their own. I think the end result is better than if my contributions hadn't been tempered by others'. Also, in the end, no one's contribution was railroaded out of town; after all of the "Yes, that's true, but X also is involved," I don't see any important bits that got left behind. Maybe the part about "bolts aren't tiny," but I am willing to see that left on the cutting-room floor because it is only connotative and may be regional. I guess this satisfactory end result is a testament to the wiki model. Anyway, that is how things seem to me. Thanks all, — ¾-10 18:00, 1 February 2009 (UTC)

I agree. For me it was a significant learning experience. I had been too willing to rely on a general sense of what the situation was as opposed to documented facts. When some of what Keithonearth wrote was inconsistent with what I believed I realized that I didn't have a particularly strong basis for some of my notions or what I had written previously. I have done just a little bit of editing in Wikipedia since this effort and I have been much more careful to rely on facts that I could document than I had been previously. One of the things that came out of this is that I am somewhat more critical of some Wikipedia articles and the screw article in particular. I think I might work on some sections a bit in the future.--Davefoc (talk) 20:17, 1 February 2009 (UTC)

Screw (Types)

The section titled "Fasteners with a non-tapered shaft" mentions "Stove bolt: Similar to a carriage bolt, but usually used in metal. It requires a square hole in the metal being bolted to prevent the bolt from turning."

My recollection of stove bolts is that they are round headed, slot drive bolts (I would rather call then screws) that are fully threaded. The size I am most familiar with is 1/4 inch with coarse threads. They are usually used with square nuts. They do NOT require a square hole.

Also, there is a "Plow Bolt", that was used to fasten plow blades to plows. These resemble a large flat head screw without a slot to drive it. The head is square, and the shoulder is similar to a four sided pyramid. The head fits into a tapered square hole in the plow blade, that locks the head into the square hole somewhat like a carriage bolt. When installed, the plow bolt provides a flush surface so plowed soil doesn't build up on the bolt head. —Preceding unsigned comment added by 67.174.193.117 (talk) 19:39, 24 December 2008 (UTC)

I researched stove bolts and determined that you are correct. As such I updated the description and added the ref I found. I also added a plow bolt entry with refs. Thanks for catching that! Wizard191 (talk) 02:52, 26 December 2008 (UTC)

Deleted link

"This link does not provide any additional information (reason for deletion)," but that is not the sole criteria for external links. Wikipedia users do not want to sift through hours of information to receive the basics. There are many people who have used this link efficiently, which I know through 4Q survey information. This is a solid link that contributes to the wikipedia page by highlighting the most desired and important information in a short span. This creates a unique resource that is efficient and palpable for users. I will not put the link back up again myself, but I sincerely believe that the link should be reinstated due to the reasoning given above.

Thanks for your time, 12.170.211.135 (talk) 18:14, 5 July 2010 (UTC)Dane Lawless

The preceding is the message I posted to the current main editor of the "screw" page here on wikipedia (message slightly modified since). I was told to bring the issue of the deleted external link up on the screw talk page. So, I am not sure if I need to attempt to gain popular support here for reinstating the link or simply bring the issue up and hope the powers that be reinstate it. The external link had been listed for close to a year and was beneficial to many. I am perplexed that one respected editor does not agree with my assessment. Thanks for everyone's time in reading and considering this issue.

98.115.66.194 (talk)Dane Lawless

Here are the Wiki guidelines which support the reinstatement of deleted EL: www.hingedummy.info/screwinfopage2.htm Writing in brackets below has been added.

What to Link

There are several things that should be considered when adding an external link.

• Is the site content accessible to the reader? [Yes]
• Is the site content proper in the context of the article (useful, tasteful, informative, factual, etc.)? [Yes]
• Is the link functional and likely to remain functional? [Yes] —Preceding unsigned comment added by 98.115.66.194 (talk) 17:51, 8 July 2010 (UTC)

I contend point 2: I don't think the link is useful. All of the info is already present. You also forgot to judge the link by: "Each link should be considered on its merits, using the following guidelines. As the number of external links in an article grows longer, assessment should become stricter. When in doubt about the appropriateness of adding new links, make a suggestion on the article's talkpage and discuss with other editors." The amount of links that were here before, as enormous, so I cleaned house, and only left those which are still useful. This article has grown a lot since your link was here. Also, your link doesn't qualify for any of the points at WP:ELYES or WP:ELMAYBE. As such, the link should not be re-added. Wizard191 (talk) 19:29, 8 July 2010 (UTC)

I looked at the proposed link and I agree that it contains nothing that can't be duplicated here, or is not already here. Plus it's a web site selling screws, so it's spam. --Wtshymanski (talk) 02:34, 9 July 2010 (UTC)

TO WTSHYMANSKI: It is far from a website selling screws. It has one advertisement on the side bar of the page. You cannot buy screws from this website, nor does it sell anything else. If you consider spam any website with one advertisement on it, you would not be able to link to the majority of the web. Your statement is completely false, with the only shred of truth based on the fact that there is a small square single ad in the corner of a content filled page. —Preceding unsigned comment added by 98.115.66.194 (talk) 13:53, 9 July 2010 (UTC)

TO WIZARD191: You have been responsive and professional. I contend that the link does qualify with all of the above including WP:ELYES and WP:ELMAYBE due to the bold reasoning given above. However, I concede that I am in the minority and this will be my last post on the matter. Thank you.

TO WIZARD191: I was hoping my last post was the end of the matter. However, Wtshymanski has also removed my www.hingedummy.info link off of the wikipedia hinge page. This is due to me posting on his talk page with a complaint. He has a personal vendetta against me. The link on the hinge page is completely legitimate and it is nonsense to argue otherwise. The entire site is dedicated to hinges and provides a wealth of information that is not present on the page. The site has installation instructions for several different types, descriptions of hinge types, hinge anatomy illustrations, hinge glossary, hinge faq's, hinge history, hinge finishes listings, door and hinge removal instructions, etc. No site has even close to this kind of comprehensive coverage of the hinge. Please talk some sense into him. This is not professional wikipedia editor behavior. I have been nothing but professional and have followed wikipedia guidelines for suggesting an external link be included. Wtshymanski has taken to name calling and pettiness in this otherwise professional debate. —Preceding unsigned comment added by 98.115.66.194 (talk) 14:18, 9 July 2010 (UTC)

I'm sorry you feel there's a vendetta against you; for it to be personal, I'd have to associate edits with a person. I do edits, not vendettas. Please read Wikipedia:External links. We don't link websites because they are good websites, we link websites as a poor substitute for putting data into the article or for linking to materials that otherwise can't be cleared to use on Wikipedia. Parts catalogs are in my opinion generally not good links for an encyclopedia. --Wtshymanski (talk) 16:29, 9 July 2010 (UTC)

The website is not a parts catalog. You are not being truthful. I just listed the websites attributes in the last post. This is clearly a vendetta against me otherwise you would not have gone out of your way to delete the other external link. Please do not insult my intelligence and the rest of the Wiki communities'. The website surpasses all qualifications and should be included on the hinge page. And the website would be considered a "poor substitute" for not putting data in the article, as there is very little in the hinge article. I would like others to comment on this issue. —Preceding unsigned comment added by 98.115.66.194 (talk) 18:56, 9 July 2010 (UTC)

Keep out per WP:ELNO#1 - the information is redundant.

Keep out per WP:SPAM - the site is a promotional vehicle for a hardware store and was added against a WP:COI.

The burden is on the editor wishing to include the link. Best to give a very WP:CIVIL argument if you want you perspective to be considered.

Looks like sockpuppetry going on as well. --Ronz (talk) 20:40, 9 July 2010 (UTC)

I am the one being civil. I was called a link spammer and have been outright lied to a couple of times. How can I be a link spammer when I have only added one link to the screw page, and when it was removed I just requested that it be reinstated? I am trying to make an intelligent arguement. Will someone join me please? Sockpuppetry? I am not sure what you even mean by that. And I did not add the link on the hinge page, it was removed after I complained about the screw page link (which I did add) being removed. And if I was COI, that does not mean I cannot edit at all. I have not even done any editing, I am just requesting that someone elses editing be undone because it was a personal attack. —Preceding unsigned comment added by 98.115.66.194 (talk) 21:00, 9 July 2010 (UTC)

Responded on your talk page. Sorry I hadn't notified you prior. --Ronz (talk) 21:08, 9 July 2010 (UTC)

Yes, you should avoid or exercise great caution, not that you cannot comment at all upon certain edits. The link deleted was clearly a personal attack, by Wtshymanksi, when you look at the screw talk page. The link on the hinge page exceeds all expectations of a wikipedia link, and was believed to be a sufficient link by many other wikipedia editors for over a year. I believe Wtshymanski, now has a personal issue or COI in this dispute and his editing should be undone. —Preceding unsigned comment added by 98.115.66.194 (talk) 19:19, 12 July 2010 (UTC)

Ronz is right, it's a promotional site for a hardware store. It shouldn't be linked anywhere unless we had an article on the Lawless family. Dougweller (talk) 20:24, 12 July 2010 (UTC)

It's borderline. However, seeing how the site has had spam issues in the past and there is consensus above, I believe it is best to leave the site out of the article. I'm sure there are plenty of other better sites out there. Wizard191 (talk) 02:01, 13 July 2010 (UTC)

All this shows is that some Wiki editors are more concerned about "spam" than they are their readers (or "winning" a debate). Hingedummy is the most informative site about hinges on the entire internet! The Wiki community is better benefited as a whole including the hingedummy link, but you guys are so concerned about "spam" that you blindly ignore an objective look at the issue. Show me a better link, that is not a book, and I will concede. I would even contend that a book would not be better, as it is cumbersome to find the desired information.

Look at the EL's for the "chair" page on Wiki. This is outrageous. Can I delete the "chair" page links and then make them prove their worth? They have Google Ads featured on them so I'd say its "spam." According to these standards, I could delete almost every Wiki EL and they would never be reinstated. On a side note, the expansive use of the word "spam" here is quite entertaining.

Thanks for responding Wizard. I must inform you though that there is not a better site about hinges than hingedummy. This is just a simple statement of fact, no hyperbole. I believe you have been crippled by your peers, but I understand your reasoning. —Preceding unsigned comment added by 98.115.66.194 (talk) 16:58, 13 July 2010 (UTC)

So, anyone want to explain the "chair" page links to me? Policy must be consistent here at Wikipedia. Please explain why the "chair" page links are considered OK, but the hingedummy link on the hinge page is not. —Preceding unsigned comment added by 98.115.66.194 (talk) 16:45, 15 July 2010 (UTC)

There are loads of bad articles, bad links, etc. That's no excuse to sink to the least common denominator. No editor has any responsbility to do anything about another article because you are unhappy. Dougweller (talk) 18:41, 15 July 2010 (UTC)

I would not associate the most apropos site concerning hinges on the entire internet with the least common denominators on the "chair" page, but I digress. I guess I will help you guys out then and begin enforcing your EL policies. —Preceding unsigned comment added by 98.115.66.194 (talk) 19:15, 15 July 2010 (UTC)

wizard191 Vincent Yotti-concrete screw

please explain your revert. —Preceding unsigned comment added by Kilbert (talk • contribs) 20:28, 7 September 2010 (UTC)

"rmv dubious claim to an inventor using a primary reference; I couldn't find anything on the internet that supported the statement". Wizard191 (talk) 20:41, 7 September 2010 (UTC)

Peter Horn edits about wood screws

Peter Hom added the following to the wood screw description section:

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.

Twinfast screw A type of wood screw with two threads (i.e. a lead of 2), so that it can be driven twice as fast.

There are some problems with these edits I think:

1. No citation for the definition of wood screw provided.
2. The definition is highly non-standard by today's usage. Many wood screws and almost all wood screws used in commercial or professional woodworking would not use a slotted head.
3. If a source for a current definition of wood screw can be found it should be used as the primary information for the section and the original sentence can be replace with it.
4. Today pan head screws are much more common than round head screws and round head screws are almost never used in any kind of commercial applications.
5. Are twinfast screws still available today? The reference is from a 1957 book. I found Twin fast being used as a trademark for self drilling screws on the internet. There might have been a market for a doubly threaded screw in 1957 when most wood screws were still driven by hand. I do not know of any usage today when almost all wood screws are power driven.

--Davefoc (talk) 06:45, 15 February 2011 (UTC)

With respect to the twinfast screws, I did some research about them recently and couldn't find any modern references to them. But I could have missed it, because I'm not familiar with them. Wizard191 (talk) 18:33, 15 February 2011 (UTC)

I also did some research and the situation seems confusing. It appears that Twin-fast may be a trademarked name which is applied to screws that don't necessarily have a lead of two. It also seems that twinfast is used generically also to describe a screw with a lead of two. It seems the term may be used often enough to justify some mention of it, but I'm still not quite sure what it is. Peter Hom has continued to make edits in a way that suggests he is not aware of this discussion of his edits. Perhaps something could be done to make him aware of this section? --Davefoc (talk) 02:39, 16 February 2011 (UTC)

I did a little more looking around: Double lead may be a generic term for what a twin-fast screw is. However double lead might apply to any screw fastener or device with a lead of two whereas twin-fast may be a more limited term. These are the most relevant sources I found:
http://www.deerwood.com/catalog/DeerwoodWoodFastenerGuide.pdf
http://books.google.com/books?id=HCEDAAAAMBAJ&pg=RA2-PA207&dq=twin-fast&hl=en&ei=2-pcTcPrAYG4sQOHjNniCg&sa=X&oi=book_result&ct=result&resnum=8&ved=0CEcQ6AEwBw#v=onepage&q=twin-fast&f=false
The second source is from a 1952 Popular Science magazine that says that the twin-fast screw is a new invention.
I never found the original source of the term twin fast although I believe it was at least originally a trademarked name. --Davefoc (talk) 09:25, 17 February 2011 (UTC)
I had begun to suspect that fine thread drywall screws were twinfast but this is confirmation:

Fine thread Drywall--Sharp point: A bugle head screw with twinfast thread, extra sharp point and black phosphate finish.
Fine thread Drywall--Drill point: A bugle head screw with twin lead spaced thread, self drilling point and black phosphate finish.

From: http://www.mutualscrew.com/media/refGuides/Stdrywallf.pdfDavefoc (talk) 10:06, 17 February 2011 (UTC)

This is good info, is there any way you can incorporate any of it? Wizard191 (talk) 02:43, 18 February 2011 (UTC)

Thank you, I am not sure exactly how to proceed. Some thoughts:
Wood screws issues

1. Wood screws only with slotted heads - this one is simple, if wood screws were ever defined as having slotted heads only this is certainly an obsolete definition now. But finding a good current documented wood screw definition may be difficult.
2. Wood screw problem in general - Rolled thread wood screws replaced all wood screws with cut threads quite awhile ago in construction and woodworking. The old fashioned screws have no usage at all I believe beyond their use for amateur repairs and perhaps some use by people trying to duplicate old furniture fasteners. The problem is finding sources that document this (assuming I'm right). Another issue is that screws used for fastening wood are evolving and there is a class of screws that are occasionally called construction screws that vary from manufacturer to manufacturer but I suspect that they are all much better than what has been available in the past. I just used some screws on a renovation project that I was doing that drove much easier than the screws I had been using and yet were significantly stronger and had enough corrosion resistance that they were rated for use with the new treated lumber. I am not sure what the manufacturer called them though(I'll look the next time I get a chance), but I don't think it was wood screws. The term construction screws doesn't seem to have been standardized on and I couldn't find a documented definition of that term.
   

Twin-Fast issues

1. The term Twin-Fast seems to have some usage as a brand name. I think, but I'm not sure, that Asian manufacturer(s) bought the rights to the name and use it as a name brand. This seems like it might be an example of that: http://www.allproducts.com/twfastener/changy/05.html
2. Even when it is used in a generic sense the term seems more like an adjective as in twin-fast wood screws or twin-fast drywall screws or twin-fast self drilling screws so just describing it under wood screws may not be entirely correct.
3. It's not clear how to spell it. twin fast, twinfast, twin-fast, and Twin-Fast are all present on the web.
4. Double thread and double lead are used occasionally as an alternative name for a twin-fast screw but I haven't found a formal definition or enough usage of those terms to verify that they are good equivalents for twin-fast.

I found a mention of a patent for twin-fast screws but I couldn't find a patent for them using any of the on-line patent search tools. I wouldn't be surprised if somebody applied for one and got shot down because of earlier art on double leaded screws.Davefoc (talk) 06:25, 18 February 2011 (UTC)

Dave, you might want to break up this discussion, because you are now talking about two topics, wood screws and twin fast screws. I was confused earlier and thought we were just talking about twin fast screws. From a search of trademarks in China and the US there are no active trademarks for "twin fast" or "twinfast". The only place that the trademark is active is in Great Britain; see [2], which shows that Trifast PLC owns it. Their website is http://www.trfastenings.com, but a search of their site shows that they don't produce it anymore. As such, it appears to have become a generic term for a wood screw with two starts. Wizard191 (talk) 16:03, 18 February 2011 (UTC)

Thanks Wizard191, I had also looked for twinfast trademarks and patents and I had found neither (except for it use as a trade mark for a diet supplement). That was some pretty good searching to find it in the UK. I am now convinced that it is a legitimate screw term that is used commonly enough that it should be included in the article. There is the remaining issue of how to treat the fact that it is more of a general adjective than just describing it in the wood screw section might imply. I would like to have found a quantitative description of its advantages and some specific information about its origin. I didn't find either. However, I am afraid that my various ramblings in this section have made it difficult to discuss anything here and I think you are right that new sections would be in order to break apart the issues.--Davefoc (talk) 17:49, 18 February 2011 (UTC)

Screw Dimensions

The correct method of specifying the dimensions of different types of bolts is summarised clearly here: http://www.hintsandthings.com/workshop/measuring_fasteners_screws.htm

This is particularly relevant to the length of CSK screws & bolts, which causes confusion if done incorrectly. I suggest adding this information in a separate paragraph. GilesW (talk) 00:06, 27 June 2011 (UTC)