Talk:Screw/Archive 1

Editting this article
I (davefoc) have been editing this article significantly over the last few days. I am new to the culture of wikipedia editing (although I am a long time reader) and I both don't want to step on anybody's toes or do things in non-standard wiki-ways. I request that anybody that sees me do something incorrectly please let me know. It is my intention to continue to edit this article over the next few weeks. I have added descriptions of the changes that I have in mind below.

Metropolitan90reinserted description of screw at the beginning of this article
I saw that Metropolitan reverted a general description of a screw in the screw article. I moved that information to the screw disambiguation page, so now it is in both places. The reason I put it there is that the Screw article is now about shafted threaded fasteners (screws and bolts). I didn't make this decision. It was underway before I started editing the page. I have tried to get hold of Metropolitan90 to discuss this issue.

It is my intention to undo Metropolitans revert, but I won't do it for several days or until I've heard from Metropolitan.

Editting the discussion page
I intend to mark issues that seem closed to me as closed with an explanation as to why they are closed and then move them to the bottom of the discussion section.

Renaming this article
I propose to rename the this article to "Screws and Bolts". The article is no longer about screw devices in general as it was when it began. I have moved several remnants of the original article that are no longer relevant to this article to other places.

Some reorganization
I have already modified the organization a bit, responding to some of the discussions about the article. The organization I propose is as follows: 1. Introduction (list of other fastener types will be moved to this section) 2. Bolt and screw Differentiation 3. Bolt and screw types 4. Head shapes 5. Drive types 5.1 Tamper resistant fasteners 6. Thread Standards 7. Tensil strength and mechanical analysis 8. Tools 9. Screw installation techniques 10. History 11 See also 12. References 13. External links

Delete legal issues section
The government document that attempts to establish a criteria for differentiating screws and bolts is referenced in the bolt and screw section. I think this is enough.

Addition of a discussion of traditional wood screw versus modern wood screws
I think this is an important topic and that it should be covered in this article. I think maybe a subtopic of Bolt and Screw types might be the place to put it.

Bolt v's Screw (closed)
Bolt seems to lead here. I have always been lead to believe that bolts and screws are different in the way that a bolt has a portion of un-threaded shank starting from directly under the head, and a screw is threaded along the whole length of its shank? Can anyone confirm this? 62.173.124.82 15:40, 18 October 2007 (UTC)


 * See the main thread below. — ¾-10 03:40, 24 January 2008 (UTC)

Closed - This issue is now discussed in differentiation between bolt and screw section. Davefoc (talk) 19:53, 27 January 2008 (UTC)

Suggestions

 * Kudos, what a great page! I'm not sure if tensile strength ratings and failures would be suitable here. Just a suggestion --Artyboats 23:16, 19 April 2007 (UTC)


 * The american quarter is not really appropriate for en.wikipedia. An english penny would be better


 * It would be good to include information on 5-lobe/point Torx screws, ie. "Tamper-resistant TORX PLUS". It's not straightforward to Google up information on these. User5910 19:34, 11 June 2007 (UTC)


 * A table of standard gage sizes? There's one for metric but not UNC/UNF.


 * Under the subheading,"Shapes of screw head," the pan head is described with a having a chamfer; actually that would describe a binding head. Pan heads are virtually flat on the bottom of the head.
 * They are chamfered on the top, however. -- Sakurambo 桜ん坊  17:16, 29 July 2007 (UTC)

Cones and cylinders (closed)
Page says that screws are threaded cones and bolts threaded cylinders, but machine screws (like the computer screw image) are threaded cylinders. 192.150.5.150 17:57, 7 September 2006 (UTC)

Closed - Error seems to have been corrected. Davefoc (talk) 19:51, 27 January 2008 (UTC)

Motion and Dual screws
I'm not an native English speaker, so I might be off with this one (i.e. you may be calling these something else, not screws), but I'm an engineer so I couldn't avoid noticing there are a few pieces of information missing from this article:

1. There is no mention about "motion screws", as we call them over here, screws which are designed for movement rather than blockage -- e.g. the one in a manual press;


 * These are called lead screws.

2. There is no mention of dual screws, both left-handed and right-handed -- these are used for applications where there is no room for the screw head, such as for mill "teeth". I don't know what the proper term is, but the idea is that both the mill and its "teeth" are precision pieces, pretty expensive to build, so its "teeth" are made separately out of tougher materials in order to allow changing them. Since there is no room on either side of the tooth for neither the screw head nor the nut, they're fastened to the mill by the means of a special, dual screw, which simply screws in both the mill and the tooth with no end visible on either side. And they do get fastened exactly because half of the screw is left-handed and half is right-handed, so turning it in one direction screws/unscrews it into/out of both pieces.

-- Gutza 0:34 14 Jul 2003 (UTC)

Would reference 1. also be called a 'shoulder screw'? LorenzoB 18:14, 27 October 2007 (UTC)

Is there a difference between lead screws and worm gears? (closed)
''Is there a difference between lead screws and worm gears ? Neither one are "fasteners", but both (along with Archimedes's screw) are included in the idea of the simple machine screw''


 * My understanding is that a lead screw is meant to turn the rotary motion of the lead screw into the linear translation of the block on it, whereas a worm gear turns the rotary motion of the worm (the long shaft with grooves) into the rotary motion of the worm gear (probably a spur gear). I don't know if you can back drive a lead screw or not, but I know you generally cannot back drive a worm gear.  Dachande 18:01, 24 July 2007 (UTC)

Closed. - The article is now about threaded fasteners and this issue isn't relevant to the article. Davefoc (talk) 19:52, 27 January 2008 (UTC)

Screws can be taken apart and replaced (closed)

 * Screws are more versatile than nails: they can be taken apart and replaced.

I do not understand what is intended by that sentence. I do know that it is incorrect. I have never seen a screw successfully taken apart and reassembled. I suspect a pronoun reference problem. --KQ 09:54 Aug 18, 2002 (PDT)


 * What that means is this: take 2 pieces of wood held together by nails, and take out the nails. The nail holes can't be reused to put them back together again. Do the same with screws, and (with decent wood, wel-drilled holes etc) the screws can be replaced. -- Tarquin

Ok, thanks. --KQ

Closed. - The ambiguity of the article on this point seems to have been eliminated.Davefoc (talk) 19:57, 27 January 2008 (UTC)

Phillips screws
Phillips screws were invented in the 1930s by Henry Phillips, and the patent has long since expired. These are "cross heads", so I fail to see why these have been listed separately. Eclecticology 21:24 Aug 18, 2002 (PDT)


 * The main reasons for mentioning Phillips screws are
 * Everyone has heard of them and despite the patent, which didn't expire, but was taken away from Phillips, they are still manufactured according to his design;
 * The design was intended to cam out, which makes them totally inappropriate for most of the uses to which they are put.
 * I will combine the cross-head and Phillips entries under Phillips.

Ortolan88 21:39 Aug 18, 2002 (PDT) Sorry, I hadn't realized it had been taken away, but even without that the basic design would have fallen into the public domain. I think that the concept of "cam out" may need to be explained somewhere. Eclecticology


 * Article says "ride out, or cam out, under strain". Everyone who has ever tried to use a Phillips will recognize what is meant, but add wording if you can improve.  Ortolan88

Okay, why were Phillips head screws "intentionally made so the driver will ride out, or cam out, under strain?" Slrubenstein


 * To hazard a guess, so that the power screwdriver doesn't rip the head to shreds / sit there immobile straining the motor when the screw gets as far in as it will go. --Brion

Uh, weren't these screws in use before power 'drivers?
 * According to the article, they were designed specifically for "use with mechanical screwing machines". Maybe not the 'lectric we know and love today, but it sounds like something that won't necessarily know when to stop turning. --Brion

I haven't looked at this in depth, but I can see another advantage to having the screwdriver ride out. It could function on the same principle as a torque wrench to prevent any damage caused by tightening screws too much. Eclecticology 01:49 Aug 25, 2002 (PDT)


 * You are right, according to this article on the web: http://www.americanheritage.com/it/2001/02/objlessons.shtml --user:Heron

This link no longer works --Bruce: user


 * There used to be an article on the Philips web site explaining why the thing was designed to cam out. It had to do with not overtightening in automotive bodywork applications.  But this document : (http://scholar.lib.vt.edu/theses/available/etd-42698-205111/unrestricted/chapter_2.pdf) suggests the matteris much more complex. -- Brunnian 02:16, 30 April 2007 (UTC)

The Phillips recess is described in the book 'One Good Turn', which has a Wikipedia article, although I haven't checked it. The book is a good read though. —The preceding unsigned comment was added by Special:Contributions/ (talk)

Threaded Fastener (closed)
Isn't a "Threaded Fastener" a category of screw? If so it should not be in a section by itself. Wake 02:15, 11 Nov 2003 (UTC)

Closed - The article has largely been reorganized to make this issue moot. See Renaming section above for more discussion.

Bolt (closed)
Bolt seems to redirect here. This could perhaps be replaced with a disambiguation page mentioning lightning bolts, crossbow bolts (ie quarrels, and quite especially the type of locking device. --blades 00:41, May 16, 2004 (UTC)


 * You are absolutely right. I have created a new disambiguation page. -- Wapcaplet 05:13, 16 May 2004 (UTC)

Closed - The issue was corrected. Davefoc (talk) 06:40, 28 January 2008 (UTC)

Threaded Fasteners
The arrangement of the page makes it difficult to define the types and uses of bolts (Hex-head, Square-head, Flange, Carriage, Plow, Stove, U-bolt, Internal drive(hex, torx) and nuts (Hex, Square, Locking (all-metal, inserted), Slotted, Castle). I would propose renaming the page Threaded_fasteners and organizing it as similar to below.

Subject: Threaded fastener

Table of contents:

1 Mechanical Analysis

2 Tensile Strength

3 Screws 3.1 Types of Screws 3.2 Shapes of Screw Head 3.3 Types of Screw Drive 3.4 Tools Used

4 Bolts 4.1 Types of Bolts 4.2 Shapes of Bolt Head 4.3 Types of Bolt Drive 4.4 Tools Used

5 Nuts 5.1 Types of Nuts 5.2 Tools Used

6 Threaded Fastener Measurements 6.1 Metric 6.2 SAE 6.3 Other &mdash; dmc 12 Aug 2004

Washers
As one of the ancient parents of this article (and former hardware-store clerk and construction worker), I concur that this organization would be much better and would accommodate all the accretions in an efficient and useful form. I wonder if there shouldn't also be a section on washers:


 * x Washers
 * x.1 Flat washers
 * x.2 Lock washers
 * x.2.1 spring-loaded lock washers
 * x.2.2 star washers

Washers are a definite part of the nut-bolt system, essential in spreading the load, preventing damage to the underlying surface, and, in the case of lock washers, holding it all together. Ortolan88 16:52, 11 Aug 2004 (UTC)


 * Washers are a good idea. It's been a week and no other input so I'll probably move the page in the next couple of days. Unless you want to. Never did find my old password. I'll go ahead and leave this page as it is until the other looks presentable. Someone with more knowledge than I and better composition skills will need to look it over. &mdash; dmc, 19 Aug 2004

I'll take a look at it after you move it. Good on you for taking this on. Ortolan88 17:15, 19 Aug 2004 (UTC)


 * I started a washer page and a belleville washer page. Am planning to merge the belleville into the washer page as I work more on it.

Bolted joint
I think there is enough information (much of it not already in screw) to start a new page on bolted joints. It could concentrate on the joint design and cover;
 * capscrews and machine screw types, ratings and markings
 * thread strength and calculations
 * nut and washer selection
 * pre-load design
 * locking mechanisms
 * Torquing tools, calculations and measuring devices
 * Torque indicating washers for structural applications

Pud 23:16, 21 Aug 2004 (UTC)


 * I'm glad I checked the discussion before moving the page. Are you suggestiong leaving the Screw page as it is and adding another page for Nuts & Bolts? Sounds appropriate and more thorough than what I was thinking. I still think, however, the Screw should be the page for the Screw as a Simple_machine and that the Screw as a threaded fastener should be elsewhere. Maybe a Threaded_fastener page could still be created describing the types and general uses of threaded fasteners with links to the various kinds. Maybe the naming conventions could be stabilized somewhat too. Nuts exist under Nut_(hardware), Washers under Washer_(mechanical), and Screw under just plain Screw. &mdash;Dmc6006 19:33, 22 Aug 2004 (UTC)


 * With a good set of cross-references, any organization will work, but Threaded fastener seems to include all the other categories. Ortolan88 20:21, 22 Aug 2004 (UTC)


 * I agree that using the threaded fastener topic would be better since it is usually used as the encompassing term for both screws and bolts. The organization proposed by dmc above seems good to me as well. --Lloydd 06:32, 22 Dec 2004 (UTC)


 * I think the Screw page is very good and wouldn't want to mess it up. It has a very nice combination of brevity, clarity and range of detail. And there is still room for growth without the page becoming unwieldy.
 * (User:Dmc6006) Yes, I would leave the Screw page as it is. I was thinking more engineering as opposed to hardware (Bolted_joint vs. Nuts & Bolts)
 * (User:Dmc6006) ...simple machine vs. threaded fastener... I think two pages, one for fastener and one for machine is viable. Screw_(simple machine) could cover worm gears, linear actuators, augars, etc...
 * (User:Ortolan88) ...cross-references..., we could use a hardware category.
 * Pud 00:36, 23 Aug 2004 (UTC)


 * I agree that the article is good one for the hardware screw and expanding it to include other fasteners could reduce its clarity. The screw page started life as a stub for the simple machine. It seems to have evolved rather rapidly into an article about the screw as a threaded fastener. Screw is used interchangeably for both meanings on this page and I don't know a good way to clear up the confusion. Also, the bolt is only briefly mentioned and much of the information applies to both bolts and screws. While both bolts and screws are applications of the screw design, they have different lineages. Anyway, that's my theory for renaming the page threaded fastener, expanding it to include all threaded fasteners, and returning this page to reference only the basic screw. &mdash;Dmc6006 14:51, 23 Aug 2004 (UTC)

Threadforms
I was under the impression that BSW (British Standard Whitworth) and BSF (British Standard Fine) were only related in that they both hail from Britain. Martin Rudat(T|@|C) 13:57, 17 February 2006 (UTC)

I think that it would be useful to mention that pipe threads are specified with a taper, so that it is possible to have the clearance between the male and female thread needed to easily screw pipe together, whilst also allowing a seal without needing to use sealant. Martin Rudat(T|@|C) 13:57, 17 February 2006 (UTC)

From what I've read in a copy of the "Engineer's Handbook" (an old edition, about as thick as a telephone directory), threadforms could easily be expanded upon to justify a seprate article. Martin Rudat(T|@|C) 13:57, 17 February 2006 (UTC)

Duplicate External Link
Lara Specialty Tools has a more extensive guide to 24 screw head types.

Removed from body of text.

Pitch vs Depth
"'The diameter of a metric screw is the outer diameter of the thread. The tapped hole (or nut) into which the screw fits, has an internal diameter which is the size of the screw minus the pitch of the thread. Thus, an M6 screw, which has a pitch of 1 mm, is made by threading a 6 mm shaft, and the nut or threaded hole is made by tapping threads in a 5 mm hole.'"

This doesn't make sense to me - isn't the pitch measured across the length of a bolt (peak to peak like a wavelength)? Shouldn't it be ''which is the size of the screw minus the depth of the thread. Thus, an M6 screw, which has a depth of 1 mm...''?

Strictly speaking you are right, but the approximate equivalance of pitch and thread depth comes from the 60 deg angle of ISO metric and UNF/C threads (ignoring the finer points about the precise tops and bottoms of the threads). --Pcrawford 11:22, 25 November 2006 (UTC).

Mechanics of use
I spent some time researching for mention of this subject. User:Rhodescus contains the references I managed to find on the web. I'm unsure how to list those references for this article in any useful way.

The rational for the entry, the proper use of screws, is deemed an important subject amongst tradesmen, technicians and other types who routinely service and maintain equipment which utilize screws (including computers!). The main principle behind the use of screws is alignment of the screw. I don't think enough attention was paid to this principle, in this article.

Also, I think my edit invalidate the statement in the second paragraph, "Screws can normally be removed and reinserted without reducing their effectiveness." A properly trained tradesman or technician who has been shown how to use screws can repeatedly remove or reinsert screws without reducing their effectiveness. Of course, that's harder to verify (but eminently true,) and depends on both the material and the screw (also true but I can't verify it.)

But is verifiable, and well known among tradesmen and technicians, that there is only one way to effectively reuse a screw in the same hole, and that the effective method is apparently counter-intuitive to most. I hope this is a useful contribution to this article, and I hope someone can show me how my references can be cited for the article, as they verify my edit.

Rhodescus 07:17, 24 September 2006 (UTC)

Why do we still get slotted screws?
This design seems to be akin to the square wheel to me? However I'm no engineer, so would really love to know an experts opinion!

Probably a combination of tradition and cheapness. Philips/Pozidrive are much more convenient for power drivers, and work very well as long as you use the correct matching tool! --Pcrawford 11:26, 25 November 2006 (UTC)

One advantage is non-magnetic slotted screws can be held flush with a special screwdriver.

- I believe the reason we have slotted screws is that everyone has a slotted screwdriver. Of all the fastener recesses, slotted is by far the worst in almost any technical performance respect - camout, stripping, off-axis drive capability, torque capacity, etc. It just sucks. The only good feature other than one that just mentioned is that you can sometimes turn a slotted fastener with a bit that doesn't quite fit, or with something that isn't a bit at all, like a coin. Many of the modern fastener recesses are quite unforgiving if you lack the exact bit for the specific recess.

I don't think cost is that much of a factor, especially for fastener recess types whose patents have expired. It's all about convenience.

I'm not sure what the comment about 'flush with a special screwdriver' means. —The preceding unsigned comment was added by Special:Contributions/ (talk)

Screws infbox
I have created Screws infbox to replace the large captioned image. Please comment and improve. Also, this might be a good time to create articles on other screw drive types. Shinhan 20:37, 27 November 2006 (UTC)

This looks like a good idea to me. I tried to add more screw head types to the screw head type image. Unfortunately it's a single image. I modified it but it is not clear to me how to modify a drawing and I didn't want to just replace it as I thought the replacement should give credit to the original creator. I think I'm going to look into what you did here to for the screw head types. Davefoc (talk) 16:54, 25 January 2008 (UTC)

Wheel stud
A new stub article wheel stud has appeared. I wondered whether it shouldn't be redirect here. What do you think? --Edcolins 13:57, 17 December 2006 (UTC)

What is a JCBC Screw?
I can't find any information on what "JCBC" stands for in this context, though Google turns up a number of places selling them. Anybody know about these? &mdash;Długosz 22:02, 27 December 2006 (UTC)
 * http://www.titanhardware.com/pdf/CS_SCREWS.pdf lists other forms in the 'JC' series - I always understood that the JC referred to 'joint connector' -- Brunnian 02:02, 30 April 2007 (UTC)

Do we need a security/tamper-proof screw page?
There are many screws designed to be "Tamper-proof". Do we need to make a page for it? --Af648 02:33, 9 January 2007 (UTC)

Capscrew photo
I added a capscrew photo because I couldn't find out here in Wiki what a capscrew is. I found out by going to the hardware store. I thought I'd save the next person the trip. --SueHay 20:33, 13 March 2007 (UTC)

captive screws
There are articles that refer to captive screws, like Mac Pro, but I don't believe Wikipedia ever actually explains what captive screws are. Herorev 05:34, 17 April 2007 (UTC)

- Captive screws are designed not to fall out once installed. —The preceding unsigned comment was added by Special:Contributions/ (talk)

Bolts versus screws (closed)
I've always be told that the difference between a screw and a bolt is that a bolt is used with a nut whereas a screw isn't. In this article it says that some screws are used with nuts. 'Cap screws may, or may not be used with nuts.'

The definition I've found for bolts is 'a long metal pin with a head that screws into a nut, used to fasten things together' and the one for a screw is 'a thin, sharp-pointed metal pin with a raised spiral thread running around it and a slotted head, used to join things together by being rotated in under pressure.'.--Jcvamp 20:34, 27 May 2007 (UTC)


 * The treatment of bolts on Wikipedia is inconsistent and unsatisfactory at present. If you try to get info on bolts on Wikipedia you are led from Bolt diasmbig page to this article which doesn't mention bolts at first, then says "A screw, by definition, is not a bolt" and directs you to this: "See also: Bolt manufacturing process" which isn't about bolts per se, there isn't an article on them. Then later the articles starts to treat bolts and screws together. It's illogical, Captain! Rexparry sydney 04:12, 31 July 2007 (UTC)

I think the description of the difference between a screw and a bolt is not as clear cut as the present article suggests. And the present article is somewhat ambiguous. I believe the situation is as follows:

The distinction between a bolt and a screw is not clearcut and usage of the terms varies. The definitions given below represent common usage. There are various other definitions that will conflict with these definitions and with each other.

Screw: A fastener that is generally driven directly into the attachment substrate or into an un-threaded hole. These fasteners are tapered and are often pointed. Wood screws and sheet metal screws are examples. Less commonly, the term, "screw" can be used to refer to all fasteners with threaded shafts.

Lag bolt )lag screw): This fastener is similar to a screw, in that it has a tapered shaft and in that is generally driven into an un-threaded hole, but it is generally larger than 1/4 inch in diameter and it generally has a hex head.

Machine screw: A fastener with un-tapered threads and a recessed drive socket (phillips, slotted, etc). These fasteners are usually less than 1/4 inch in diameter.

Cap Screw: The term "cap screw" can be used interchangeably with bolt, however the term is often associated with hexagonal socket (allen) head drive screws. The term, "socket cap screw" is a more precise term for a fastener with a hexagonal socket head drive.

Bolt: This fastener is similar to a machine screw, except that it is generally 1/4 inch or larger in diameter and it most often has a hex head, however hexagonal socket head drive bolts are common.

Tap Bolt: This fastener is a bolt that has a completely threaded shaft.

Bolt definition issues.

Distinctions between bolts, and cap screws have been made based on the length of the threaded area with cap screws being threaded almost to the head and bolts being threaded only partially up the the shaft.

Distinctions between bolts and screws have been made based on the whether the fastener was intended to be attached with a nut or not. Since it is normally the case that a particular fastener can be used in both applications this kind of definition leads to ambiguity as to whether a particular device is a screw or a bolt until it is installed.

A document that attempts to make a formal distinction between a screw and a bolt has been generated by the US government because different tariffs apply to the two kinds of fasteners. The document is linked to in the article under legal issues Davefoc (talk) 04:49, 23 January 2008 (UTC)

...and "hurricane" and "typhoon" are two words for a tropical cyclone

 * Thanks for the link. It's interesting and unsurprising that a government tried to make a formal distinction between a screw and a bolt in response to the wording of a tariff law. But etically speaking, I think that the usage overlaps too much to say that there is a formal difference. I know that people make various distinctions, e.g. whether the shaft's threads engage both mating parts, but the linguistic reality is that it amounts to one person or group's technical distinction versus another's, with the other 98% of the population meanwhile not even trying to differentiate. I think that the people who carry this differentiation to silly extremes are usually monolingual. It's a bit like saying that a hurricane is "different" from a typhoon because it happens in the Atlantic instead of in the Pacific. They're both tropical cyclones. But it is the monolinguist's instinctual urge to think that because both words exist, there simply must be two different meanings to be differentiated by the "proper" speaker. Now, in cases such as "acronym" versus "initialism", I am absolutely in favor of maintaining a clear and simple distinction for the sake of easy precision. But in the case of "bolt" versus "screw", I think it's impractical to try to enforce a nomenclature distinction, because there are a dozen wordy versions of what exactly the difference is supposed to be that most people won't remember clearly even if they ever heard it in the first place. My 2¢! — ¾-10 03:36, 24 January 2008 (UTC)

Thanks for the response Three-quarter-ten, I didn't want to update the section on screw versus bolt without some feed back. I think it should be updated and I agree with your comments. I thought that the differentiation between bolt and screw section should be changed so as to describe the ambiguity of the issue, plus a brief discussion on attempts to formally divide them. I just realized there is already another section on types of screws and bolts. So I withdraw my comment about needing an additional section Davefoc (talk) 20:24, 24 January 2008 (UTC)

I don't know if you read that official screw/bolt discussion but it almost worked as a joke about the excesses of government bureaucracies. What was even funnier is that the guy that wrote it seemed to have been confused on the meaning of coarse and fine with regard to screws. He seemed to see coarse and fine as defining the precision of the fastener and as such it served to help differentiate screws from bolts. Davefoc (talk) 22:41, 24 January 2008 (UTC)


 * Ha! The mighty government setting us all straight! :-)


 * Today I was thinking about the various senses of "bolt" (door bolts, rifle bolts, crossbow bolts), and how prior to the 19th century there were probably plenty of smithy-forged bolts (in the fastener sense) that had no threads, holding wooden things (such as carriages and trunks) together. I imagine them being held on in various non-threaded ways, such as clinching, "nuts" that were cold-swaged on or shrink-fitted on, or whatever (I don't know much about smithing), rather than threaded. Then once screw threads became cheaply practical, bolts probably started having screw threads on them a lot more often. And I thought about old rivets in girders from the 1800s through the 1940s, which are kind of the all-metal-construction analog. (And electric welding largely replaced riveting kind of like threaded bolts replaced non-threaded ones.) I suspect that this technological backstory explains the idea of "bolts" being differentiated from "screws" by their passing through the substrate without threading into it, then only threading into a nut. But if so, it seems pointless to try and continue the distinction today, because of all the well-blended usage (e.g., threaded lag screws being called lag "bolts"). Oh well, I am basically just thinking aloud. Anyway, good discussion! — ¾-10 03:48, 25 January 2008 (UTC)

I have been musing along similar lines. There is definitely some historical basis for cap screw/bolt distinctions. I found an old book on line that talked about SAE and USS screw standards making the distinction. But not one screw company that I looked at made a similar distinction today. Some companies used the term cap screw and some companies used the term bolt but no company used bolt to describe one thing and cap screw to describe another.

Well, I hope I didn't piss anybody off, but I reworked the screw type section quite a bit today, with an eye towards incorporating what we've been talking about. I divided it into tapered and non-tapered fasteners, and talked just a little bit about the bolt/screw issue there. I think I'm going to rework the bolt/screw differentiation section tomorrow and discuss in a little more detail some of the distinctions that have been made and how common usage varies from them. This is almost the first time I've edited an article on wikipedia and I don't want to violate any generally accepted practices. Davefoc (talk) 09:04, 25 January 2008 (UTC)

Consensus resolution (Closed)
I updated the bolt/screw differentiation section to describe what I believe the situation is. I would appreciate any feedback or disagreements with the approach. Below is a list of of links to some of the information that I looked at before writing that section: http://books.google.com/books?id=NRXnXmFRjWYC&pg=PT1021&dq=ASME+B18.2.1&ei=cnubR-GzMZb4tgPMg5GoCg&sig=d_-06UqzCt5yCehD3kWwVnqO-Cw#PPT1021,M1 http://www.cbp.gov/linkhandler/cgov/toolbox/legal/informed_compliance_pubs/icp013.ctt/icp013.pdf http://www.usenet.com/newsgroups/sci.engr.mech/msg00958.html http://euler9.tripod.com/bolt-database/boltdef.html http://books.google.com/books?id=BtYbqYNbg0QC&pg=PA701&dq=bolt+screw+sae+uss&ei=jp6bR-WTJKiwtAOcgLmoCg&ie=ISO-8859-1

I believe this section should be included inside the screw type discussion and intend to move it there unless somebody objects.

Dave

Davefoc (talk) 22:03, 26 January 2008 (UTC)


 * Wow! Fantastic job, Dave. I really believe that the section you have written well describes the reality of current usage. I was pleasantly surprised to see you mention head bolts because I had also thought about that very example. So, IMO, great job. Re the move, sounds good to me. — ¾-10 22:55, 26 January 2008 (UTC)

Thank you for the kind words Three-quarter-ten. I believe this is now a closed issue and I am marking it as such.

Closed - consensus view was incorporated into the article.Davefoc (talk) 06:49, 28 January 2008 (UTC)

While I can see the sense of renaming the page to incorporate both screws and bolts, isn't the capitalization as it currently stands (Screw/Bolt) a bit out of place? Seems to me that per the usual standards, it should be screw/bolt, which doesn't even exist as a redirect yet. --J. Randall Owens | (talk) 05:49, 12 February 2008 (UTC)

3-2 screws
I have a 3-2x5mm machine screw (for circuit boards). What kind of sizing is 3-2? I don't see any notation like it under ISO metric screw threads, Whitworth, BA, or Unified Thread Standard.

Tri-wing?
Actually it's widely used in aviation. I believe it was originated from Lockheed aircraft L-1011 TriStar era, also used on other aircraft like MD-11 (welp, are those tri-engined aircrafts also mean tri-shaped fastener? :D).

The idea was that it would cam out easily when tightening, to prevent overtightening, but grip hard when loosening. So it was not intended for the tamper-proof purpose, and as for tamper-proof purpose, I think it was choosen because of the screw can be made very small sized than other type (gameboy screw? =D).

In the real aviation use, these screws are very nasty, as the flute is shallower than positive drive it can get damaged easily if one doesn't apply enough pressure or maintain a straight angle when loosening. Comparable to Airbus' Torq-Set but slightly different reason, the Torq-Set's flute is set as if the tightening grip is more than loosening grip, so one can easily overtorque it and became very very difficult to remove as the loosening grip is lower, it will just slip/cam out, damaging the screwhead in the further process. The best method is by always using a torque gauge when tightening a screw (as in the maintenance rule) but in the real world, that's very tedious work limiting it only used in the critical parts of the aircraft.

221.126.136.80 13:51, 27 June 2007 (UTC) Katt

Great info, there is a page about Tri-Wing screws, maybe you would like to contribute to it but you need a source/reference Af  648  07:56, 23 July 2007 (UTC)

Misc. comments
Tri-Wing, Torq-Set, and Pozidriv are all designs and trademarks of the Phillips Screw Company: http://www.phillips-screw.com/. Another recent product of theirs is Mor-Torq. Yes, these are all primarily aviation or aerospace fasteners, but are sometimes used as security screws because the recesses are relatively uncommon. However, given that you can now buy comprehensive sets of 'security' bits anywhere, including Sears, I would not want to use them as security fasteners.

Because they are aerospace fasteners, they have design objectives for specific applications. For instance, the torque to remove a fastener often far exceeds that to install it because the fastener becomes frozen. Hence the fastener recess may be designed so as to withstand the larger removal torque.

Phillips also developed the ACR (Anti Camout Ridges) on the Phillips recess, which helps to hold the bit is the screw. Note that by design, Phillips will camount under excessive torque.

The list of fastener recesses is incmplete and out of date. For example, I don't see Torx-Plus listed. Like Torx, it is a product of Camcar Textron, but the patent on Torx-Plus is still running, which has limited its adoption. I also don't see the Recex/Quadrex/square-Phillips combo recess. There are many other on the market these days that are not listed here, e.g. ASSY, XZN (commmonly called triple-square to advoid trademark issues) and found in some cars. There ia also an interesting variant on the familiar hex (Allen, a trademark) recess.

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 Special:Contributions/ (talk)

For those interested in the more technical aspects of fasteners, check out the fastener trade bimonthlies 'American Fastener Journal' and 'Fastener Technology International'. Also, check out the publications of the International Fastener Institute (IFI). —The preceding unsigned comment was added by Special:Contributions/ (talk)

Nettlefold's Patent No mention in the history of woodscrews of Nettlefold's patent - the tapered tip with the screwthread tapering to the tip. —Preceding unsigned comment added by Brunnian (talk • contribs) 21:17, 22 December 2007 (UTC)

Bristol
If I am able to obtain reference material, should I include the relatively obscure 'Bristol' drive ? LorenzoB 18:20, 27 October 2007 (UTC)
 * Please do. -- Sakurambo 桜ん坊  15:09, 29 October 2007 (UTC)

Here's a link to some information on the bristol head screws: http://www.newmantools.com/hand/splinekey.htm

This is a link to a drawing of the bristol head pattern similar to the drawings used for the head patterns of other drive types: http://www.newmantools.com/hand/spline.jpg —Preceding unsigned comment added by Davefoc (talk • contribs) 04:57, 23 January 2008 (UTC)

Early Metal Screws?
The article claims that "Metal screws used as fasteners did not appear in Europe until the 1400s," but provides no source for this claim. Nor does the article specify what year or place metal screws were first used, or for what purpose. Were the earliest metal screws used as instruments (thumbscrew) of torture? The article also makes no mention of how early screws were made. More information on the early history and use of metal screws would be desirable here. ThaddeusFrye 19:30, 8 November 2007 (UTC)

United Thread Standard
The United Thread Standard Section starts off saying "The US has its own system of thread designation" and then goes on to say that like 85% of the world uses it in almost everything. What the hell? it sounds like some one started POV and then some one else brought it back to the other POV and now it's really awkward. When I read it, it felt like it started with "The Crazy US uses it's own insane system" and then switched to "It's used by the entire f***ing world." So first we need documentation that most of the world does in fact use US threads, (VERIFY AND CITE THE CLAIM) and then assuming that we can prove that second statement true, we need to reword the opening to something that flows better, instead of pulling a POV u-turn on the reader. Am I completely nuts, or does this make sense to anyone else? Dachande (talk) 01:42, 21 January 2008 (UTC)
 * Also, if the United Thread standard is responsible for 85% of the world's fasteners, it should NOT be the 4th friggin' thread standard on the list. That makes it No.1 regardless of your opinion of ISO, SI/English units, 1/4"-20 vs M6, America/Europe, Lions/Tigers, Pandas/Koalas, Red wine/White Wine, Beer/Whisky or anything else. Dachande (talk) 01:45, 21 January 2008 (UTC)

Types of screw drives section
A note to this article-there's also a rare type of screwdrive (for a reason), whose shape is a triangle. it's called triangle recess, or TP3. 15:03, 28 January 2009 (UTC) —Preceding unsigned comment added by 212.150.245.250 (talk)

There is also a 12-point drive. Commonly used on 4x4 drive shafts. A 12-point socket/wrench fit them.

Carriage bolt, coach bolt and Brunnian's edits
Brunian has made several edits based at least partially on a particular definition of coach bolt.

I was not able to find an internet site that used the same definition as Brunian for coach bolt. The most similar term for what Brunian seems to have intended was coach screw that is defined in places as equivalent to lag screw (lag bolt). Brunian's definition of coach bolt seemed to be equivalent to lag screw (bolt). Unless a source can be found for Brunian's definition of coach bolt his edits with regard to coach bolt should either be removed or edited.

Internet search results with regard to the definition of Coach bolt

(coach bolts and carriage bolts are the same) http://www.buildeazy.com/glossary/bolt.html Coach/carriage bolts: are round headed bolts with square shoulders that resist rotation when located or driven into place. They can be called coach bolts or carriage bolts depending on which part of the world you live in. The head end of the bolt does not need a washer, but the other end of the bolt (the nut end) usually does.

(uses term coach bolt to describe what is a carriage bolt in the US) http://www.screwfix.com/prods/33264/Bolts/Coach-Bolts/Threaded-Coach-Bolts-A4-Stainless-Steel-M8-x-80mm-Pack-of-10 http://www.dealclick.co.uk/product/10908590/Unbranded-Zinc-Coach-Bolt-M12-X-90-With-Nut.php

(defines coach bolt as same as carriage bolt in UK) http://encarta.msn.com/dictionary_1861687848/coach_bolt.html U.K. Same as carriage bolt

(uses coach bolt as equivalent to carriage bolt, uses coach screw as equivalent to lag screw) http://www.fastfixdirect.co.uk/code/navigation.asp?fType=Fasteners&MainCategoryID=6 http://www.interiordezine.com/index.cfm/Interior_Design_Fittings_and_Fixtures/Fixings_2

Davefoc (talk) 16:52, 4 May 2009 (UTC)


 * Agreed - thanks for the research Davefoc. Wizard191 (talk) 18:26, 4 May 2009 (UTC)

I removed the reference to coach bolt from the screw/bolt differentiation section, I changed coach bolt to coach screw in the screw types section and I changed the definition so that it references the lag screw definition. I think this issue is closed unless Brunnian provides documentation for his edits with regard to this. Davefoc (talk) 17:39, 6 May 2009 (UTC)

Types / differentiation sections
I want to combine the "differentiations" section with the "types of screws and bolt" section. The differentiation section is talking about various types of screws and bolts, so it feel natural to me for it to flow into the various types. Plus the types section has and entry for "screw" and "bolt" that references the "differentiations" section. I think it should be pretty easy segue with something like: "In this article we are going to classify screws into two major categories based on...". Let me know what you think. Wizard191 (talk) 00:32, 23 May 2009 (UTC)


 * There is definitely duplication between the 2 sections currently. But I am having trouble envisioning how to merge them. I would say give it a shot if the inspiration strikes. Could hash it out on a subpage first. — ¾-10 02:37, 24 May 2009 (UTC)


 * I attempted it in my sandbox and it didn't go very well. It made sense in my head at the time. I think I'm just going to move the "types of screws and bolts" section under the "differentiation" section. Wizard191 (talk) 12:37, 25 May 2009 (UTC)

Explanation for reversion of good-faith EL change
One would think that the info would be "surely available through noncommercial sites", but I have actually looked into that and found that the best info on fasteners and tools tends to come from supply houses. I deduced that the reason for this is that the only people with the time and money to make these really great information resources (ie, thousands of pages of brief descriptions with great photos) are the ones whose livelihoods are tied to it. For example, the MSC, McMaster-Carr, and Enco catalogs are collections of information (especially the photos) that would be excellent to have for Wikicommons, but of course it cost them a lot of money to amass this resource and they only give it away to the extent that it leads people to buy from them, which is entirely understandable. Eventually we can get GFDL photos of every type of fastener and tool in the world, but it takes time, which equals money. Here's a toast to continuous improvement and pro bono moonlighting. — ¾-10 23:25, 29 May 2009 (UTC)


 * I had a discussion with the reverting editor on his talk page and am in the process of trying to add the info to the article. I've just uploaded SVG versions of the head marking and just need to start on the table. But I have to agree with you that there's a lot of real good info out there at commercial websites (especially McMaster). I know I personally use it on a daily basis for design information at work. Wizard191 (talk) 23:43, 29 May 2009 (UTC)

What to do with bolted joint?
So I've been working on some of the mechanics of this article, but the sections still need a lot more work. Right now I'm apprehensive to make more drastic changes, because of the bolted joint article, which has some good information, but overlaps some of its content with this article. For instance, both articles have info on bolt strength, proper torquing, and property classes. Now I realize there's going to be a slight overlap on some information, but I think we need to figure out properly split the information. Right now this article is 70 kB, so it's pretty big, but I suppose one option is merging bolted joint into this article. However, right now I'm leaning more on taking the strictly screw information, like property class information, and moving that from bolted joint into this article, and then taking the information about torquing, etc., and moving that to bolted joint. However, I'm definitely open to other ideas. Wizard191 (talk) 01:02, 10 June 2009 (UTC)

129.97.36.75 's edits about computer controlled torquing
The revisions in question are these: Wizard191 version: Large volume users such as auto makers frequently use computer controlled nut drivers. With such machines the computer in effect plots a graph of the torque exerted. Once the torque ceases to rise (the point where the bolt begins to deform) the machine stops. Such machines are often used to fit wheelnuts and will normally tighten all the wheel nuts simultaneously.

129.97.36.75's version: Large volume users such as auto makers frequently use computer controlled nut drivers. With such machines the computer in effect plots a graph of the torque exerted. Once the torque reaches a set maximum torque chosen by the designer, the machine stops. Such machines are often used to fit wheelnuts and will normally tighten all the wheel nuts simultaneously

I believe that two different ideas have been confounded here. The use of computer controlled tightening machines to achieve the optimal torque by tightening until there is a drop in torque and the use of computer controlled tightening machines to automatically achieve a particular preset torque.

I suspect that lug bolts are torqued until a specific torque is reached and are not torqued to achieve the optimal torque for resistance to unwanted resistance to loosening. I am not sure though and neither editor has provided a citation for their edit.

I believe that some head bolts are torqued using the procedure that Wizard191 mentioned since there are some head bolts which are designed to be used only once.

Either way it seems like the paragraph as it now stands has problems because of a lack of citations and the possible confounding of concepts. --Davefoc (talk) 20:58, 16 June 2009 (UTC)


 * FWIW, I didn't write that paragraph, however I believe you are right DaveFoc. There are two different concepts/procedures being described and they are both probably right. As such, they should both be described. But I think a source needs to be found for each concept first. Wizard191 (talk) 21:38, 16 June 2009 (UTC)

Triangular slot?
I've seen screws with a triangular slot, similar to the Robertson head but having an equilateral triangular depression instead of a square hole. I've seen it primarily used in plastic kid's toys, e.g., the kind you get with a McDonald's Happy Meal. Any idea what this head type (or driver type) is called? — Loadmaster (talk) 17:56, 17 July 2009 (UTC)


 * See top of this talk page. Ortolan88 (talk) 15:33, 19 July 2009 (UTC)

Acme Thread
What about the Acme thread, a trapezoidal thread from used for feedscrews, high-torque and self-braking mechanisms? Does it deserve a bit more detail than being stuck with the obsolete threads? —Preceding unsigned comment added by Brunnian (talk • contribs) 21:22, 8 August 2009 (UTC)


 * Really there needs to be a small topical section created for leadscrews thread forms, which contains the acme thread form. Wizard191 (talk) 22:57, 9 August 2009 (UTC)

Acme thread are hardly obsolete. They are commonly found on bench vises and heavy-duty C-clamps.

"locate objects"?
All that comes to mind is a metal detector or something. That part should be rewritten. - Craig Pemberton 09:52, 12 November 2009 (UTC)


 * I think the poster is referring to this sentence in the first paragraph: "Their most common use is to hold objects together or locate objects." I agree with the comment.


 * It is not clear to me what locate objects is meant to mean.--Davefoc (talk) 16:09, 12 November 2009 (UTC)


 * Does this help: ? Wizard191 (talk) 17:47, 12 November 2009 (UTC)


 * Yes it's better and I thought that was what you meant. But I'm not sure it's useful to have "position objects" in the sentence at all.  The distinction between holding objects together and fixing an object into position seems very subtle to me.  One can attach a picture to the wall using screws or one can position a picture on the wall using screws.  It seems like it's just two different ways of saying the same thing.  Maybe I still don't get what you mean by position objects.--Davefoc (talk) 18:30, 12 November 2009 (UTC)


 * I'm really referring to things like jack screws, where the screw is used to set a position but it doesn't actually anchor anything. Wizard191 (talk) 18:40, 12 November 2009 (UTC)

maximal diameter?
The sizing section says: "The numbering system follows a roughly logarithmic series where an increase in each screw number size approximately doubles the tensile strength of the screw and the screw number is found by $$d=.060+(\# \times .013)$$, where "d" is the nominal diameter." However, I suspect that maximal diameter is meant instead of nominal? —Preceding unsigned comment added by 64.105.21.209 (talk) 04:06, 16 December 2009 (UTC)


 * Thanks for the heads up. I've fixed it in the Unified Thread Standard as I'm going to trim up the section here. Wizard191 (talk) 15:35, 16 December 2009 (UTC)

Unified thread standard
I'm having huge difficulty believing 'At least 85% of the world's fasteners are dimensioned to Unified thread dimensions'. It is certainly contrary to my experience, where ISO metric threads seem to dominate. I've tried to buy UNC fasteners on every continent to repair US made machines, and rarely succeeded immediately outside the USA. Even Canada seems to use more Metric than Unified threads. Brunnian (talk) 14:13, 15 July 2009 (UTC)


 * You are quite right. There's no such source as "The World Fastener Review". I think it's some really old sneaky vandalism. Wizard191 (talk) 14:45, 15 July 2009 (UTC)

Check with the Industrial Fastener Institute (IFI), a very real organization. Joe Greenslade is the director. —Preceding unsigned comment added by 72.72.20.207 (talk) 17:43, 20 January 2010 (UTC)

Darysys October 4, 2009 edits
Darsys, made a number of edits to the Fasteners with a tapered shank (self-threading screws) section: They provided interesting information, however I believe there are some issues with his edits.

I thought adding the ® was a good edit and a reasonable thing to do, so much so that when I put that item in the list I included it originally. Somebody came through and took it out without comment. I didn't know why. I thought if somebody thinks it should be removed again, they might stop by and explain why before they delete it again.
 * (Teks® screw)


 * Wizard191 deleted the trademark symbol. He said that it violated Wikipedia standards to use it. He seems to be right: MOS:TRADEMARKS--Davefoc (talk) 08:58, 4 October 2009 (UTC)

I thought this was useful information and probably should be retained. However these are not the bad old days of this article (of which I was a participant) when unsourced material was just added willy nilly. At least for new material, sources should be supplied otherwise we are going fall farther behind on proper sourcing for this article.
 * Addition of size information about Teks screws

I didn't know that particle board screws have asymmetrical threads and that is interesting, but I don't know what asymmetrical threads are. Perhaps a reference to where that is explained would be helpful. And the no source comment applies to this item also.
 * Asymmetrical threads on particle board screws

If you look at cross-section of an individual thread, it is often in the shape of an upside-down V with both sides symmetrical about an imaginary axis that runs from the tip of the thread to the bottom of the profile, like an isosceles triangle. Asymmetrical threads have been optimized for the material the screw is designed for. The cross-section of the threads are not symmetrical: one side is steeper than the other. This configuration may be to reduce installation torque or to maximize the pullout force required to rip the fastener out of the material (as opposed to unscrewing it). —Preceding unsigned comment added by 72.72.20.207 (talk) 17:43, 20 January 2010 (UTC)

Again good information. This is difficult to source because it includes a conclusion that most deck screws have this kind of tip. I'd settle for a couple of cites of prominent manufacturers of deck screws that have auger tips. Also, some link to a place where auger tips are described would be helpful. —Preceding unsigned comment added by Davefoc (talk • contribs) 02:40, 4 October 2009 (UTC)
 * Auger tip for decks screws

Auger point, also called Type 17 point, are indeed common in deck screws because they do not require predrilling. I don't think they are universal as there may be some other proprietary designs, but I can say that the auger point is the one feature that distinguishes deck screws from 'standard' flat-head wood screws (other than the corrosion-resistant coating). Note that there are many other screws that have an auger point. —Preceding unsigned comment added by 72.72.20.207 (talk) 17:43, 20 January 2010 (UTC)

One-way and Clutch are NOT the same, not even close
I am surprised to see this kind of error on Wikipedia, shown on the screw profiles at the right edge of the article. A one-way screw is as illustrated, a modified slotted recess with ramped edges that prevent removal without a special tool. It is a type of security or tamper-resistant/tamper-proof fastener. A clutch recess, sometimes called a butterfly screw, comes in two basic styles, A and G. Both are 'traditional' recesses in that they are symmetrically formed into the head; installation and removal are equally easy. It is uncommon but not really considered a security fastener. —Preceding unsigned comment added by 72.72.20.207 (talk) 17:43, 20 January 2010 (UTC)


 * Quite right; I've corrected the template. Wizard191 (talk) 18:42, 20 January 2010 (UTC)


 * That very topic had been bugging me for a while, but I couldn't decide how to address it, because I couldn't think of how to differentiate one-way from clutch within the constraints of the B&W (i.e., nongrayscale) stylized drawings, which is the illustration style used throughout that template. I had visions of a vector graphic with a gradient screen to stylistically represent the sloping contours of the one-way head (not sure if I described that very well—I know what I mean!), but my Adobe Illustrator skills are still too remedial to execute such a slick idea. Anyways, there's always tomorrow … — ¾-10 00:40, 22 January 2010 (UTC)

Flange bolts?
No mention is made of flange bolts in this article. This would be helpful information. Wakablogger2 (talk) 01:07, 1 March 2010 (UTC)


 * I've added a section about flanged heads. Thanks for the heads up. Wizard191 (talk) 16:15, 1 March 2010 (UTC)


 * Wow, very nice. Thank you :) Wakablogger2 (talk) 02:06, 2 March 2010 (UTC)

Taptite screws
User 86.181.159.85 added a description of Taptite screws to the "Fasteners with a tapered shank (self-threading screws)" section.

Taptite seems to be a particular brand of screws. Perhaps there is common usage of the word, taptite for a particular kind of screw, but based on a review of the company's web site it looks like they make a range of screws and the use of the word taptite for a particular kind of screw may not be appropriate here.

There is already an entry for "thread rolling screws" in the "Other threaded fasteners" section. The term, thread rolling screws, may be the generic name for the screws that were described by 86.181.159.85 as taptite. Perhaps the "thread rolling screws" entry should be moved to the "Fasteners with a tapered shank (self-threading screws)" section? The text for the section might be derived from the existing "thread rolling screws" text and the text created by 86.181.159.85.--Davefoc (talk) 18:01, 10 April 2010 (UTC)


 * Agreed. I've removed the taptite section and moved the thread rolling section up. Wizard191 (talk) 16:55, 13 April 2010 (UTC)

spanner head
Should be renamed to "snake eye" or "pin head", spanner implys a hexagon or square head. Try a google search for a "pin spanner" —Preceding unsigned comment added by 92.30.36.125 (talk) 20:15, 14 May 2010 (UTC)


 * The Wikipedia policy for inclusion is a reliable source; a google search is not a reliable source. If you can find a reliable source then feel free to add the other names in addition to "spanner". Wizard191 (talk) 21:30, 14 May 2010 (UTC)

Thread Rolling Diagram needed
The article needs a diagram to show how the dies are used to roll threads. There are two or three basic machine types. One rolls the thread between two flat dies (one stationary, one moves at right angles to the shank (back & forth). Another type of machine rolls the thread between two arc dies, one concave, one convex. One or more convex dies is mounted to an inner shaft which rotates. The concave die is fixed. The bolt/screw is rolled between the dies, being inserted on one side of the fixed die, and rolling off completed on the other side. A third type is used to create threaded bar stock (and to roll shot). This machine uses cylindrical dies, and both dies rotate.  The dies rotate in the same direction so that the bar stock rotates in place(the opposite direction) along its axis.  The rotational axes of the two dies are not parallel but are offset by a bit so that as they rotate, they pull the barstock through the machine.

Note also that the die rolling process can shape the shank of the bolt or screw. --71.214.233.109 (talk) 18:15, 14 July 2010 (UTC)


 * See thread rolling. Wizard191 (talk) 18:58, 14 July 2010 (UTC)