Why righthand threads?

[jaCK HobsonParticipant @jackhobson50760]

I vote the filing of rh threads.

As some might be getting fed up of me going on about it – there are no left handed files outside watchmaking (for use by right handers on a lathe).

[roy entwistleParticipant @royentwistle24699]

Has anyone noticed the number of medical people who are left handed ? Personally I can only wind anything, like a drill, or a fishing reel, left handed, a lot of things I can use either

[Mick B1Participant @mickb1]

I’d’ve thought it goes back to the movement of the the sun across the sky. If you’re forced to choose, you’d pick a familiar direction as the default, and move away from that by exception if there were a reason to do so.

Not sure why many British Imperial smallarms had barrels rifled with a left-hand twist, though.

[paul raynerParticipant @paulrayner36054]

Mick b1, perhaps they were for use in the southern hemisphere?

[Russell EberhardtParticipant @russelleberhardt48058]

Hmm…., perhaps it stems from something even older than Archimedian screws, DNA?  The most prevalent form of DNA has a right handed helix.

Russell

[jaCK Hobson]

On jaCK Hobson Said:

On not done it yet Said:

I used to occasionally invigilate at GCSE/GCE examinations.

Any particular subject?

Exams clearly come up as block entries.  All GCSE Maths would be separate from GCSE English.  GCE A levels might occasionally be mixed in.

One exam slot might be all science and the next slot all Geography, so each dealt with as separate entities.  One did not choose a specific subject to invigilate.

[BazyleParticipant @bazyle]

Interesting one about the files – normally don’t notice they have a twist.

[Grindstone CowboyParticipant @grindstonecowboy]

Thinking of how threads are cut on a lathe (wood or metal), it seems easier to work from right to left with a chisel if you are right-handed and naturally the workpiece would be revolving towards you resulting in a right-hand thread. Maybe the Archimedean screws were done like that?

But that could be a chicken and egg situation resulting from an earlier convention.

Rob

[Michael GilliganParticipant @michaelgilligan61133]

?

Do ambidextrous people prefer using rivets ?

MichaelG.

[Michael Gilligan]

On Michael Gilligan Said:

?

Do ambidextrous people prefer using rivets ?

MichaelG.

It depends if they like big hammers.

JA

[BOB BLACKSHAW 1Participant @bobblackshaw1]

Right and left hand threads on the bottom bracket on cycle frames and pedels

Bob

[Martin ConnellyParticipant @martinconnelly55370]

I wonder if anyone has ever done a survey of the wooden threads on things like an olive press or fruit press. These predate filing metal threads or thread cutting lathes so may have set a convention for threads long before these latter processes. It always amuses me how often cartoonists draw threads incorrectly, and I don’t just mean left handed instead of right handed. They draw a left handed thread and then show something being tightened in a way that actually requires a right hand thread.

Martin C

[John HaineParticipant @johnhaine32865]

Who knows when the righty-tighty became dominant but one trigger could have been Maudslay’s screw-cutting lathe.  As someone said earlier, a lathe most naturally cuts a RH thread.  Once accurate RH threads could be generated at will the preference could become dominant.

[Neil AParticipant @neila]

Did Maudslay’s screw-cutting lathe have a left hand thread lead-screw? Most of the screw-cutting lathes I have seen have a left hand thread on the lead-screw so that the saddle moves toward the chuck when the lead-screw is rotated clockwise.

From the photographic images of screw threads that I have seen that predate Maudslay, it would seem that the right hand thread had been in common use for a long time. That is not to say that left hand threads were not used, many of the woodcut images of presses show a left hand thread, but I could not guarantee the accuracy of these images.

Perhaps a visit to one of the science museums to view the exhibits might give a clue as to when screw threads came into common use and which hand they were.

Neil

[Neil AParticipant @neila]

I thought the following article might be interesting in the history of screw threads. I’m afraid that it does not answer the original question of right hand threads though.

Neil

https://exarc.net/issue-2024-2/ea/production-roman-metal-screw-threads-extended-version

[Neil A]

On Neil A Said:

…Perhaps a visit to one of the science museums to view the exhibits might give a clue as to when screw threads came into common use and which hand they were.

…

There is a photo of Maudslay’s lathe in E T Westbury’s Metal Turning Lathes at page 15, too small to determine the leadscrew hand but caption says it’s in the Science Museum.

ETW confirms the method of making an accurate screw by the tangential application of a tool to a soft rotating cylinder.

[Michael GilliganParticipant @michaelgilligan61133]

https://collection.sciencemuseumgroup.org.uk/objects/co8637173/model-of-henry-maudslays-screw-cutting-lathe

MichaelG.

.

P.S. …would anyone care to explain the caption on this:

https://collection.sciencemuseumgroup.org.uk/objects/co46546/machine-screw-thread-making-tool-by-henry-maudslay

[Michael GilliganParticipant @michaelgilligan61133]

[Michael Gilligan]

On Michael Gilligan Said:

…

.

P.S. …would anyone care to explain the caption on this:

https://collection.sciencemuseumgroup.org.uk/objects/co46546/machine-screw-thread-making-tool-by-henry-maudslay

MichaelG:

Is your point that the photo of the rotab-like exhibit is mis-captioned?

[JAParticipant @ja]

I found the photo of Maudslay’s original screw cutting lathe on the internet a few days ago (Graces Guide) and was intrigued by the head stock being on the right. I then realised that the print may be the wrong way round, a mistake commonly made by “non-literate” editors etc. I could have then gone back to earlier published photographs of the lathe but there are more important things in life.

JA

[ega]

On ega Said:

On Michael Gilligan Said:

…

.

P.S. …would anyone care to explain the caption on this:

https://collection.sciencemuseumgroup.org.uk/objects/co46546/machine-screw-thread-making-tool-by-henry-maudslay

MichaelG:

Is your point that the photo of the rotab-like exhibit is mis-captioned?

My point is that I was unable to reconcile the text with the image .. and yet [a little later] Google AI gave a broadly similar description.

At first sight the device looks like a compact version of Jesse Ramsden’s circular dividing engine, but the text states otherwise.

I am seeking enlightenment.

MichaelG.

[peak4Participant @peak4]

Does this Getty photo provide any assistance?
I’m not attempting to explain how it works
https://www.gettyimages.co.uk/detail/news-photo/tool-for-originating-screw-threads-this-tool-was-made-by-news-photo/90742045

It shows a nascent master screw thread poking out of the large hole.

Just found this old thread on here, showing the same photo

Linear division in early 20th century

This doesn’t provide an explanation , but I still found it interesting; Opera browser’s built in translator made it readable for me
https://stanki-expo.ru/novosti/tpost/pxzoib0eu1-stanok-dlya-promishlennoi-revolyutsii

Bill

[duncan webster 1Participant @duncanwebster1]

This explains how it works, scroll down to para 46

[Michael GilliganParticipant @michaelgilligan61133]

Thanks, Bill & Duncan

It’ s rather distressing to see how much has slipped  the memory these last few years.

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, as for writing from left to right, and assuming that right handedness was already a dominant feature, the practical reasons could have been that you can see plainly what you have already written, and you are less likely to smudge what you have already written, and more so when writing in ink was established. Even when writing vertical, it’s more practical to start at the top, for the very same reasons.

Regards Nick.

[Author]

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