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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[edit]

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[edit]

Please add something about crankshaft runout. According to 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)


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)


I removed this; Al-Jazari's mechanism was a wheel that set several [[crank pin]]s into motion, with the wheel's motion being circular and the pins moving back-and-forth in a straight line.<ref>{{citation|title=Islam and Science, Medicine, and Technology|last=Sally Ganchy|first=Sarah Gancher|publisher=The Rosen Publishing Group|year=2009|isbn=1435850661|page=47}}</ref> 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[edit]

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[edit]

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

Orphaned references in Crankshaft[edit]

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":

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.[edit]

"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)