Talk:Crankshaft

The history section stops at about 1600 and the piece then jumps straight to the internal combustion engine. In the 18th C the steam engine was held back by patents on crank motions. Surely it should cover how these came about and what the use was. I've removed : "In the Wankel engine, the crankshaft and the chamber in which it rotates is shaped to provide a compression and expansion area allowing the forces caused by detonation of the fuel to act directly on the crankshaft."

I thinks it's unaccurate IMO there is no crankshaft in a Wankel. But I can be wrong this could a problem of slight difference in technical terms between French and English. But even if there's something taht can be called a crankshaft, I don't think the detonation can act directly on it. Ericd 18:03 Apr 12, 2003 (UTC)

"diametrically opposed five (five pistons with three set diagonally opposed to two)." This is joke ! Try to divide 5 pistons in 3 sets ? Ericd 22:10 Apr 12, 2003 (UTC)

To Ericd: The word "set" is meant as "placed" or "aligned" rather than as "a group." There are three cylinders placed opposite of the other two. Get it? Also, the crankshaft in a Wankel motor does, indeed, have the compression chamber incorporated into it. As the crankshaft rotates, the chamber comes around and lines up with it's other half in the block. I think you are splitting straws over the name of the part. The crankshaft in a motor drives the transmission which then drives the drive shaft. Whether or not there are pistons driving offset points on a shaft or a shaft is spinning around from diagonal forces placed directly upon it via explosions, it is still cranking around. [Alan Evil]


 * I don't thing that 5-cylinder have a flat crankshaft the most rational solution is to use a 72° angle. The engine will have good balance but even firing. However I have somewhat changed my mind about this. I was believing that all 3-cylinder had a 120° crankpin angle until I discovered that some version of the Laverda Straight-3 mortocycle have a flat crankshaft (120° crankpin angle). Thus I believe now that some constructor may have designed flat-plane straight-5. As of today with CAD, counterweigth and balance shafts an engineer can design a very imbalanced engine that don't explode. However in the absence of source I don't know how a straight-5 crankshaft is designed.

BTW the crankshaft in a Wankel is not a crankshaft but an eccentric shaft it does not have the compression chamber incorporated into it the compression chamber is the "rotating piston" (the rotor) Ericd 22:12, 23 August 2005 (UTC)

The original reason I visited this page is to find out what "crankshaft" is in sexual terms. I believe it has something to do with scatalogical (sp?) sex acts but I'd rather not visit the sites which pop up when the term is Googled. Gotta admit it creates some weird images. [Alan Evil]

Crankshaft throw
The article refers to the "crank throw" as synonymous with the "crank pin". Surely this is inaccurate. Strictly speaking the throw is a measurement (sometimes taken to be the distance from centre of crankshaft to centre of crank pin, sometimes twice that distance) and not an object. If it can be an object then surely it would be the crank arm, i.e. that part of the crankshaft that is at right-angles to the shaft axis and provides the crank-pin offset?

crankshaft runout
Please add something about crankshaft runout. According to www.thewarfields.com/HotRodBlogEngineAssy4.htm it has to do with the straightness of the crank, but I was hoping for more info than that. Thanks

I'm not sure if that level of detail is appropriate for this article, but I can give you some additional info, albeit a little late. Crankshaft runout tolerances are pretty tight and depend on the make of engine. I have seen runout as little .002 (.004 total) of an inch clamp the crankshaft in tightened main saddles to the point that it could not be rotated with a 2' long bar attached to the flange. Runout can be difficult to measure as spinning the crankshaft in v-blocks is only as accurate as the roundness of the main journals it's spun on. The only truly accurate way to measure runout would be to mount the crankshaft in some type of "centerless" system so that it can be adjusted to its own centerline, then spun to check runout. This is the system of mounting that many crankshaft grinding machines employ. The best way to check for the hobbyist or backyard mechanic would be to install only the front and rear main bearings (both halves, if applicable), coat them with assembly lube, install the crankshaft and tighten the saddles to specified torque ratings. A dial indicator can then be placed on the center or closest to center main journal to read runout as the crankshaft is rotated. Again, you are at the mercy of the roundness of the main journals for accuracy, but you will know what runout you have with the crankshaft in its future environment. A crankshaft with an acceptable amount (or none at all) of runout should spin easily by hand with all bearings installed and torqued, unless you're using a rope-type rear main seal. Those add a lot of resistance to rotation until they have been run a bit. Good Luck! MovingTargetB2 (talk) 21:01, 20 January 2009 (UTC)

Nomenclature
Who knows what the piece of a crankshaft between a crank pin and the center line of the crankshaft is it called? It is a web?

AdrianAbel (talk) 17:55, 17 February 2009 (UTC)

removed
I removed this; Al-Jazari's mechanism was a wheel that set several crank pins into motion, with the wheel's motion being circular and the pins moving back-and-forth in a straight line. as it does not describe a crankshaft (crank pins do move back and forth) nor does it describe the thing that Al-Jazari built, either the source is unreliable or it is not accurately transscribed.J8079s (talk) 23:35, 22 August 2009 (UTC)


 * I'm not sure what exactly you mean? The crank pins do move back and forth in a crankshaft. Jagged 85 (talk) 21:16, 3 October 2009 (UTC)

Earliest evidence for crank and connecting rod
I removed the inclusion of the alleged ancient Egyptian crank and connecting rod mechanism because it rests on erroneous interpretation of the cited reference and a lack of true understanding of the mechanism. In the context in which the crank and connecting rod mechanism appears, Robert Moores (p.146) does not speak of the ancient Egyptian saw, but of its "modern configuration as a slab-making machine". The entire absence of a crank and connecting rod mechanism in the ancient machine is corrobated by fig. 11 which shows the "operation of the 4th Dynasty drag saw". Gun Powder Ma (talk) 01:50, 4 October 2009 (UTC)


 * I don't have access to Moores' entire article, so I just left it as "may have" in this article. From what I have read, it appears it was in reference to the ancient Egyptian device. Could you maybe quote the whole thing to make it clearer? Regards, Jagged 85 (talk) 02:11, 4 October 2009 (UTC)



This type of saw, called a drag or frame saw, has been used to cut soft and hard stones for centuries, and is reported to date to at least 300 b.c. In its modern configuration as a slab -making machine, multiple blades are clamped in a frame and adjusted apart to the desired thickness of the finished slab. The frame hangs from four bars that connect its corners to an elevating (feed) mechanism above. According to Bowles, "as the frame moves back and forth, actuated by a crank and connecting rod (pittman), the cutting blades lift toward the end of each stroke. This permits sand to wash under them, and as they start back on the return stroke the blade bears on the sand which abrades the stone rapidly." Please note that the supposed Ganchy reference (p. 47) in Crankshaft does not support what you claim it says. Gun Powder Ma (talk) 02:30, 4 October 2009 (UTC)


 * The Ganchy reference does support what's written, but it's actually on page 41. I've just updated the reference in the article to the correct page. Regards, Jagged 85 (talk) 02:47, 4 October 2009 (UTC)

Andre Bahous
Andre Bahous is a Lebanese born Canadian. He is quite possibly Wikipedia's biggest fan. —Preceding unsigned comment added by 207.188.64.195 (talk) 19:19, 12 March 2010 (UTC)

Orphaned references in Crankshaft
I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of Crankshaft's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.

Reference named "Hill2": From Vacuum: Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64-69 (cf. Donald Routledge Hill, Mechanical Engineering) From Al-Jazari: Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64-9 (cf. Donald Routledge Hill, Mechanical Engineering) 

I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT ⚡ 17:25, 17 May 2010 (UTC)
 * This is now repaired. - Salamurai (talk) 20:27, 20 May 2010 (UTC)

Flying Arms.
"In some engine configurations, the crankshaft contains direct links between adjacent crankpins (without an intermediate main bearing, as is usually the case), thus half as many crankthrows as pistons are used." I don't think this is right. Could someone check this?Longinus876 (talk) 11:44, 23 June 2016 (UTC)

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undue weight
Do you think your over all article would be better suited if you removed piston stroke and engine configuration from it.Jkloop12 (talk) 06:01, 21 October 2017 (UTC)
 * No, because engine configuration has crucial effects on crankshafts. Crankshaft shape (relative twist) controls the firing order, inline six engines break crankshafts through harmonic resonances, unless damped.
 * The weakest section here is the vast dump on "Manufacturing". Andy Dingley (talk) 09:44, 21 October 2017 (UTC)

material redacted
An anon editor added this to the very top of the article:

And I removed it because, whatever it is, it doesn't belong before the lede. I archive it here in case it can/should be salvaged for use in the article (it is not ref'd tho). Herostratus (talk) 04:17, 10 August 2018 (UTC)

Crank and Connecting Rod in China
There is an issue in this article regarding the source from White which says:
 * '"Yet a student of the Chinese technology of the early twentieth century remarks that even a generation ago the Chinese had not 'reached that stage where continuous rotary motion is substituted for reciprocating motion in technical contrivances such as the drill, lathe, saw, etc. To take this step familiarity with the crank is necessary. The crank in its simple rudimentary form we find in the [modern] Chinese windlass, which use of the device, however, has apparently not given the impulse to change reciprocating into circular motion in other contrivances'."'

This is incorrect, the Chinese did "change reciprocating into circular motion in other contrivances". The evidence for this is overwhelming. This article list examples of the crank and connecting rod of other places, so I replaced the above wrong statement with examples of the crank and connecting rod from China. Why delete those examples when the source was already given?

Source title: International Symposium on History of Machines and Mechanisms, page 249

Publisher: Springer Science and Business Media

From the book, it says:
 * "From the above discussion, the crank and connecting-rod mechanism featured with eccentric lug was adopted for a long period of time in ancient Chinese blasting apparatus, textile machinery and agricultural machinery, and its appearance was no later than the Western Han Dynasty. It was first applied in manually operated quern and long, and the gradually evolved into different crank connecting-rod devices, used in the inter-conversion of rotary and reciprocating (rectilinear) motion in specific situations".


 * In page 245 the author shows a Chinese waterwheel operating a crank and connecting rod to blast air for a furnace.
 * In page 241 the author showed treadle spinning wheels (from the Nong Shu) that operated through a crank and connecting rod.
 * In page 239 it showed a water-driven flour-sifter driven by "a connecting rod and an eccentric lug" (from the shui ji mian luo).
 * In page 237 and 240 the author showed crank and connecting rods in a fascimile of a Han dynasty stone relief, as well as a Han dynasty model of a quern using the crank and connecting rod.

The author says in page 237:
 * "The eccentric lug is actually a crank, also a kind of crank-and connecting rod mechanism. So far as we know, the eccentric lug system of manually operated quern and long in the Han Dynasty was the earliest crank mechanism in China; it was also the earliest application of the crank and connecting rod in the world"

'--ArchimedesTheInventor (talk) 10:40, 2 April, 2020 (UTC)


 * White is aware of such examples as he himself cites the Han era bellow and the farmyard machine in his discussion (p. 104). Still, he arrives at the conclusion you want to remove, because the Chinese knew only these and very few more uses. Note that a single German technical book of the 16th century gives as much as 45 different machines that use cranks. So it is fair to say, as White does, that the potential of cranks wasn't fully realized in China. Gun Powder Ma (talk) 00:21, 3 April 2020 (UTC)


 * White is talking not about Chinese use of the crank (if we're talking just the crank, the Chinese used the crank multitudes more than just those listed above) but the "crank and connecting rod" which is more than just the crank. Not all cranks "convert reciprocal motion to rotary motion" or vice versa, ergo White was not just speaking of some generic crank. White is saying that the Chinese had limited use of the "crank and connecting rod", and the only example he gave is a quern operated by crank and connecting rod from the 15th century when quite clearly there are examples from much further back as far as 200 BC to 200 AD, as shown above. So clearly White was unaware of the other uses the Chinese had for the crank and connecting rod. The ancient Romans had only one example given for the crank and connecting rod, but that is listed in the article instead of "Romans didn't have it". I'm giving four examples of Chinese usage for the crank and connecting rod, again not some generic crank. So I see no reason why it's somehow justified to delete the list of usages the Chinese had for the crank and connecting rod, and replace it with a quote from White used in such a way that a casual reader would assume the Chinese didn't have the crank and connecting rod until the 20th century.
 * If we are just talking about crank, the list of Chinese usages would be many many times more than what I listed above, but the quoted section from White is not talking about some generic crank, but the "crank and connecting rod". At the very least, you should allow me to edit in the different usages the Chinese applied to the "crank and connecting rod" into the article, just like what's done for all the other states.

'--ArchimedesTheInventor (talk) 7:55, 2 April, 2020 (UTC)
 * Note that Gun Powder Ma has a specific vendetta in mind - to prove that x thing was invented in Europe first. See spat over Ottoman usage of arquebuses in History of gunpowder, arquebus, and List of Chinese inventions. All of which Gun Powder Ma has specifically edited with the purpose of proving x thing was done in Europe first. Qiushufang (talk) 06:48, 7 April 2020 (UTC)
 * For examples, see User:Gun Powder Ma's changes to the the "Middle East" and "Far East" sections post mass deletion restoration. Before: ], After: . Near complete removal of all content for China and Middle East whilst adding specifically disparaging material.Qiushufang (talk) 01:01, 8 April 2020 (UTC)

Al-Jazari and crankshaft
I am not able to verify several claims here. The claim " According to historian Donald Routledge Hill, Al-Jazari invented the crankshaft" is referenced to Hill p 23-24, but Hill only say "Two of these Models (80 and 85) contain an action which approximates to that of a crankshaft, anticipating by some five centuries the first known description of a crankshaft in Europe.33 The Banü Müsa's crank would not have allowed a full rotation, but only a small modification was required to convert it to a crankshaft." There is nothing about Al-Jazari inventing crankshaft.

Similarly I am not able to verify the claim "The author Sally Ganchy identified a crankshaft in his twin-cylinder pump mechanism,[31] including both the crank and shaft mechanisms". I search Islam and science, medicine, and technology for crankshaft word but found nothing, can somebody verify it? DMKR2005 (talk) 01:06, 21 April 2021 (UTC)

I am also not sure that Sally Ganchy is reliable source, as she is not historian of science. Searching for her, she appeared to write a few popular books on variety of unrelated things. DMKR2005 (talk) 01:14, 21 April 2021 (UTC)

This article needs a little work
Reading this reminds me of early Wikipedia articles. Within are conflicting writing styles, unfinished categories, some cut off sentences, and the general lack of references

The appropriate tag should be added 2605:A601:A13D:2600:F8E8:5C01:CF19:DD35 (talk) 03:46, 30 August 2022 (UTC)

History is duplicated from “crank” entry
I don’t see a compelling reason to include the whole history of “crank” here under “crankshaft.” I think we can start with the 1640 entry which first mentions the conversion of reciprocal motion to rotary motion or vice versa. 209.122.194.120 (talk) 13:47, 21 February 2023 (UTC)