Right hand threads

This topic has 47 replies, 27 voices, and was last updated 31 October 2017 at 19:19 by Mike.

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29 October 2017 at 19:47 #25597
vintagengineer
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@vintagengineer
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29 October 2017 at 19:47 #324337
vintagengineer
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@vintagengineer
Who decided right hand threads would be the norm?
29 October 2017 at 19:53 #324340
HOWARDT
Participant
@howardt
Probably the same person who decided which way was clockwise.
29 October 2017 at 19:53 #324341
Michael Gilligan
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@michaelgilligan61133
I don't know … but I'm sure there's nothing sinister involved

MichaelG.
29 October 2017 at 19:56 #324344
Tractor man
Participant
@tractorman
Can’t imagine any other reason than it just happened that way. I know some will say there must be more to it than that but if you reverse every single system left hand threads would be the norm.
29 October 2017 at 19:59 #324345
Samsaranda
Participant
@samsaranda
Maybe it has something to do with the predominance of individuals who are right handed. Dave
29 October 2017 at 20:02 #324347
speelwerk
Participant
@speelwerk
Most likely someone from the European continent, if threads was a British invention left handed would have been the norm. Niko.
29 October 2017 at 20:04 #324349
Robbo
Participant
@robbo
Posted by Michael Gilligan on 29/10/2017 19:53:20:

I don't know … but I'm sure there's nothing sinister involved

MichaelG.

Nice one Michael!
29 October 2017 at 20:13 #324350
Ed Duffner
Participant
@edduffner79357
Leonardo Da Vinci perhaps?

Ed.
29 October 2017 at 20:21 #324351
SillyOldDuffer
Moderator
@sillyoldduffer
I reckon it's to do with right handers and they way threads were first cut in wood. Threads were marked on a wooden pole by wrapping a chalked cord around it. Then the thread was chiselled out using the chalked spiral as a guide. Right handed people are in the majority and they naturally wrap the cord to create a right-handed thread. It's quite awkward for right-handers to wind left-handed (and vice versa).

I've no idea why being right-handed is more common than being left-handed. I would have expected us to split 50-50. Where's a biologist when you need one?

Dave

PS Just seen Ed's suggestion about Leonardo da Vinci. As he was a leftie, I may be in trouble!

Edited By SillyOldDuffer on 29/10/2017 20:24:13
29 October 2017 at 20:34 #324356
Speedy Builder5
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@speedybuilder5
Its strange that the French adopted RH threads when everything else seems to be opposite !
BobH
29 October 2017 at 20:44 #324359
Martin Whittle
Participant
@martinwhittle67411
Despite (or is it indeed because of?) being a southpaw, I find that screwing clockwise is the natural way to drive a screw.

I was still surprised yesterday, replacing our oven fan motor. I saw and fully understood from the interweb that the fan retaining nut was left-handed, but which way did I "REALLY WANT TO" and still try to turn it to no avail? But successful repair job in the end .

Martin
29 October 2017 at 20:45 #324361
HOWARDT
Participant
@howardt
Archimedes? But then everything is Greek to some all the time, and only most of the time to engineers until they ask the question here.
29 October 2017 at 20:46 #324362
HOWARDT
Participant
@howardt
Go on, tell me he wasn't Greek.
29 October 2017 at 20:56 #324364
vintagengineer
Participant
@vintagengineer
Archimedes screws are left hand threads normally.

Posted by HOWARDT on 29/10/2017 20:45:35:

Archimedes? But then everything is Greek to some all the time, and only most of the time to engineers until they ask the question here.
29 October 2017 at 22:29 #324373
Mick B1
Participant
@mickb1
They were following the sun, which appears to rotate clockwise through the sky. Hence anticlockwise or left hand threads are 'widdershins' – against the sun.
29 October 2017 at 23:05 #324378
Hopper
Participant
@hopper
Maybe so that cutting forces in the lathe when screwcutting are against the hefty headstock bearings, not against the more flimsy tailstock, and in those days fixed centre, when cutting a LH thread? (Remembering that in those days lathes were not easily reversible at the flick of a switch so screwcutting was most easily done in the normal forward rotation mode.)

Edited By Hopper on 29/10/2017 23:06:56
29 October 2017 at 23:15 #324380
Mike Poole
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@mikepoole82104
Posted by Michael Gilligan on 29/10/2017 19:53:20:

I don't know … but I'm sure there's nothing sinister involved

MichaelG.

It makes it easier for dexterous people to tighten them.

Mike
30 October 2017 at 07:35 #324392
martin perman 1
Participant
@martinperman1
Posted by SillyOldDuffer on 29/10/2017 20:21:48:

I've no idea why being right-handed is more common than being left-handed. I would have expected us to split 50-50. Where's a biologist when you need one?

Dave

PS Just seen Ed's suggestion about Leonardo da Vinci. As he was a leftie, I may be in trouble!

Edited By SillyOldDuffer on 29/10/2017 20:24:13

I've always found that being left handed makes us the clever ones

Martin P
30 October 2017 at 08:00 #324393
Perko7
Participant
@perko7
I suppose it also aligns with common phrases like 'right-hand man' which assign the position of power or authority to the right hand. In many cultures the right hand is used for all the important things like eating, drinking, and social interaction, whereas the left hand is reserved for less appealing duties.
30 October 2017 at 08:07 #324394
not done it yet
Participant
@notdoneityet
Ever since there were armies (and possibly before that) 'everyone' had to be right handed – couldn't tolerate lefties, with arms on the 'wrong' side.

Even down to about a hundred years sgo, those that were left handed were cajoled into using things right handed. Most machines, by then were only easily operated that way. I doubt if left handed scissors were made that long ago, for instance! (anyone know for sure?).

I put handedness down to mothers feeding babies (after breast feeding). Sat on knee, fed with right hand and baby will try to hold the spoon with the right hand. Possibly goes back to stronger heart beat on the left side (ventricle v atrium) and the way babies were carried.

As for screws, I have no idea except that most screws were tightened once and never removed, which meant it was just the easiest way for a right handed person to use them.

Edited to add that perhaps it goes deeper than hands (and feet). One eye is nearly always the master eye. That may even have arisen from mothers feeding babies thatvway round. Might just be chicken and egg – which came first?

Edited By not done it yet on 30/10/2017 08:12:06
30 October 2017 at 08:33 #324396
Clive Brown 1
Participant
@clivebrown1
"Archimedes screws are left hand threads normally."

I was with my grand-son in an adventure play-ground last week.

There were two hand-operated archimedian screws lifting water from a stream several metres to the sand-pit. Both were right-handed, ie clockwise rotation at the top to lift water. All the children that I saw seemed to turn them the correct way without much thought about it.

Edited By Clive Brown 1 on 30/10/2017 08:34:41
30 October 2017 at 08:57 #324397
martin perman 1
Participant
@martinperman1
Posted by not done it yet on 30/10/2017 08:07:56:

Even down to about a hundred years sgo, those that were left handed were cajoled into using things right handed. Most machines, by then were only easily operated that way. I doubt if left handed scissors were made that long ago, for instance! (anyone know for sure?).

I put handedness down to mothers feeding babies (after breast feeding). Sat on knee, fed with right hand and baby will try to hold the spoon with the right hand. Possibly goes back to stronger heart beat on the left side (ventricle v atrium) and the way babies were carried.

According to my mother I was left handed from day one, my parents made no attempt to try and make me use my right hand but the school did, unsuccessfully, but certain school equipment, desk calculators etc were difficult to use but it made me adapt and now I use both hands just as well with one exception, if you put a knife in my right hand I become incapable of any control.

Martin P
30 October 2017 at 09:08 #324398
Ian S C
Participant
@iansc
Handedness is controlled by the brain, a RH person uses the LH brain to control the RH side if the body and a LH person uses the RH brain. About 10% are left handed, but not all people who appear LH are, some of you will have heard of the Kiwi left hand golfer Bob Charles, He's RH, but when he was a kid the only golf clubs around belonged to another member of the family(aunt, mother, can't remember) who was LH.

Ian S C
30 October 2017 at 09:35 #324400
vintagengineer
Participant
@vintagengineer
To draw the water up they have a left hand thread so when turned clockwise the water is drawn up.

Posted by Clive Brown 1 on 30/10/2017 08:33:34:

"Archimedes screws are left hand threads normally."

I was with my grand-son in an adventure play-ground last week.

There were two hand-operated archimedian screws lifting water from a stream several metres to the sand-pit. Both were right-handed, ie clockwise rotation at the top to lift water. All the children that I saw seemed to turn them the correct way without much thought about it.

Edited By Clive Brown 1 on 30/10/2017 08:34:41
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