OK, its not strictly a woodworking questio.
But, from time to time I read comments form some "Engineering types" who might have the answer.
Now, wiseacres, I know turning to the right tightens screws and nuts and so for and turning counter-clockwise/Left, loosens/unscrews/etc.
But why? Is there some practical consideration, some engineering principle involved in the decision to make screws and nuts and such in this manner? Or, like a toilet flush, is it done just teh opposite in China? ;)
My guess is that most people are right-handed, and it is easier to twist your right hand clockwise than counterclockwise. (At least for me it is.)
That said, there are cases where the design calls for "opposite" threads to keep things from becoming unscrewed through normal use. Left-side bicycle pedals screw onto the cranks lefty-tighty, for instance.
Chris
clockwise is the direction that a right handed person has the most twisting strength. beyond that, it's kind of one of those traditional things whose origins are lost in time.
On Nov 18, 12:48 am, Hoosierpopi wrote: Or, like a toilet flush, is it done just teh opposite in
actually...Chinese toilets don't flush in the opposite direction....not even in Australia.
They don't swirl at all here in Oz. Toilets on this end of the planet in the UK and at least some of the countries in Europe don't have as much standing water in them as I have seen in North America. The first time I went to a bathroom stall in the US, I saw the water level and I thought it was broken. Flushing is not done by a whirlpool effect but through the gravity feed of the water in the tank.
Just part of the rich tapestry of life I suppose.
Mekon
Roger Woehl has brought this to us :
(snip)
Wiki disagrees and proposes that the Coriolis effect is too small to make any difference to swirling of water in a toilet.
Then all those garbonzos that put the bread-bag ties on backwards on Maier's bread are left handed, huh? Just one of life's little annoyances that crop up, especially before the morning caffeine kicks in... :)
From a triple digit channel on cable TV, there was this program:
A long time ago during the Greek civilization (500BC??) this guy invents a bilge pump for ships at sea. (you know, the ships that has all them slaves pulling on oar's.) It is a one man crank type of thing that looked like a screw set inside a hollow wood tube (auger.) The edges of the inner screw shaft was water tight against the outer tube. The bottom tip was at the bottom of the ship and as the sailor (slave?) turned the crank the water was lifted up and out of the many ship. This was the first cylindar wedge. Later, the ship board propellor, and aircraft propellor would take on the same shape as a section of the cylindar wedge. Telephone pole post hole diggers (augers) use the same shape and rotation today.
Archimedes Screw pump:
Looking at the model they built for the TV show crosswise, and you see the shape of a screw (auger.) The acient version of this was also turned in a right hand clock wise manner. IIRC, they had an ancient drawing of the bilge pump showing the 'righty-tighty' (as in tidy clean up, or ship-shape) turning of the cylindar wedged shaped bilge pump.
Related to today's screw threading? Your guess as good as mine. But the treading of a screw does go back to before Roman Empire time. The problem is, there is only a small handful still here this NG that remember so long ago.
Phil
?Ton yhw
Had one of the Semitic nations perfected the screw, might be another matter.
about which you know absolutely nothing. It is not an authoritative source for much of anything except maybe wiki itself. There's a reason that many colleges and high schools do not accept wiki as a reference on term papers.
Never realized that Archimedes developed that pump originally as a bilge pump. Clever fellows those old Greeks.
FWIW Greek and Roman warships did not use slaves for rowers--that didn't come until the Middle Ages and the advent of gunpowder, which changed tactics from "ram and board" to "standoff and shoot". Merchant ships were not in general powered by oars at all.
A colleague of mine actually tested this by watching water swirl down drains in the northern hemisphere, near the equator, and the southern hemisphere during various travels over a year or so. The results:
So based on his observations, the effect is weak, but it is there.
Kevin
No kidding. That piece of crap operation has information which is only as good as the most recent edit. In 30 seconds it can be trashed--subtley or precipitously--rendering it utterly worthless. An "information resource" which is potentially worthless is essentially, practically worthless.
So it would be harder to loosen than to tighten. ;~)
Becauuuuuuuuse, Righty Tighty Lefty Loosey was the official national standard developed before the direction of the screw was decided upon. Screw direction was anticipated as being a problem and therefore the "easy to remember" safety reminder was created before the direction of the screw was determined. I'm quite sure that the government was put in charge of developing this standard and the tax burden on its citizens was enormous, resulting in a debt that is still nagging us to this day. ;~)
I wouldn't call it "utterly worthless". It's very handy for answering questions like "Who is this Paris Hilton person that everybody is on about" or "What in the H-E-double-toothpicks is a bunyip". Not the basis for a scholarly paper, but tells enough to satisfy idle curiosity and let me determine whether I want to delve deeper.
Having done the same experiments myself, and using coriolis and geostrophic winds in air navigation,
On Nov 18, 8:16 am, "J. Clarke" wrote: >
Mekon wrote: > > Roger Woehl has brought this to us : ". The coriolis effect goes in the other direction in the Southern Hemisphere."
Is it possible to detect the Earth's rotation in a draining sink?
Yes WIKI is not necessarily "the authority,"but it does comport with the other reliable sources in this instance, Moreover, given the history of the effect and its original application, the "determined by the force of the water entering the commode" approach makes sense. Indee, why would the water in a vessel NOT ROTATE even absent an open drain if this effect applied at the macro level?
But we digress from the question inspiring this dialog, no?
the ancient Greeks tidied up their ships in English?
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