Rotary controls. Direction of rotation?

[Station X]

Quoting from this thread:-

https://www.vintage-radio.net/forum/...ad.php?t=36228

Most water and gas valves turn clockwise to reduce the flow. Volume controls work the other way. Confusing? My late mother often turned a volume control the wrong way. We also say "wind up the wick" when we want it louder. Presumably by analogy with oil lamps. In this case the rotation is the same way.

Fluid valves open anti-clockwise. That's because they have right hand threads. They have right hand threads because early threads were cut on lathes. Lathes have the headstock on the left to suit a right handed person. Cuts are always made towards the headstock with the work rotating towards you. Hence a right hand thread results.

Plug cocks like those on my gas cooker also operate anti clockwise, so I guess the convention was continued. Why then do rotary electric controls increase clockwise?

[Peter.N.]

I suppose because turning it clockwise is 'advancing' as with time. You can always swap the ends of the pot round though.

[Station X]

You can always swap the ends of the pot round though.

Not with a log law pot you can't.

[Mike-repairman]

Hmm, because they always have I guess; but someone must have decided the first time a volume control was used.

Similar analogy with slider controls on a mixer desk, up for an increase in volume.
With one exception, the BBC spec is to have them increase when sliding down (off at the top) hence all BBC desks have them the 'wrong way'.

Mike.

P.S. Just saw Peter's reply (advancing with time) guess that could be the answer.

[Alan Stepney]

The rotary motion to fit with clocks and "clockwise", goes back to sundials and the normal rotation in the nothern hemisphere (where sundials originated).

Once one has become accustomed to that, it is but a short step to thinking that any rotary motion advances in the same way, as it has become intuitive.

[Station X]

In my house there is one exception to the clockwise rule. The room thermostat for the central heating is rotated anti-clockwise to increase the temperature. Why should that be?

[Skywave]

I just would like to say "thank you" to Graham for Post 1. I've always wondered about that - now I know.

Al. / Skywave.

[Nickthedentist]

Originally Posted by Station X

The room thermostat for the central heating is rotated anti-clockwise to increase the temperature. Why should that be?

I think that's universal too. The temperatures are marked in the usual sense, i.e. running from low to high as you read clockwise, but they're marked on the knob rather than the enclosure hence the need to to turn anticlockwise to increase the temperature.

Again, that may be due to the thread-cutting convention mentioned above, where mechanical stats are concerned. But the convention has now carried over to all-electronic room stats where the knob is coupled to a pot or rotary encoder.

Nick

[Nickthedentist]

Another convention is the cueing lever on turntables. Pushing it away from you always raises the arm... except on Duals

[russell_w_b]

Originally Posted by Station X

In my house there is one exception to the clockwise rule. The room thermostat for the central heating is rotated anti-clockwise to increase the temperature. Why should that be?

Because you're holding the tail and wagging the dog!

[Dave Moll]

Originally Posted by Nickthedentist

I think that's universal too.

This seems to confirm what I previously only suspected - that my central heating belongs to an alternative universe

(with apologies for the abominable quality of the image)

[BGmidsUK]

From the photo that thermostat looks identical to mine (a Switchmaster). The scale on mine is clockwise though




BG

[AC/HL]

A curiosity. On another thread
( https://www.vintage-radio.net/forum/...ad.php?t=36296)
there is a photo of an 1155.
The logging scale is clockwise as usual, but the set tunes anti-clockwise on all ranges. Did the designer think in wavelength

[wireful3]

Many years ago an article in an Electronics Magazine discussed the new control panels for ships. These were in effect "fly by wire " systems with rotary potentiometers on the panel controlling the final actuators. There was an interesting situation where users from an engine room environment tended to expect to turn the speed control anti-clockwise to increase speed. They saw it as a steam valve that operated this way. Others from a different background however saw it as a "volume control" and expected clockwise rotation to increasee speed.

[georgesgiralt]

Something funny :
My wife always go the wrong side when operating any control. So you often jump when she want to reduce the radio or HIFI volume ...
The oven knob goes "the wrong way" and she also fail. So I think there is no rule ;-) almost for ergonomics ....

[Andrew2]

Why do water taps go the opposite way to volume controls? Taps go clockwise to turn the water off, v/c's go anti-clockwise to reduce the volume to zero.
I've just been asked this question by a friend and told him it had been discussed here, but I couldn't recall the answer (if any).

[Radio Wrangler]

Classical taps designs go the way they do so they can be made with right-handed threads for which taps (the other sort!) and dies are more plentiful. They pre-date volume controls.

David

[Al (astral highway)]

Because of the screw pitch, Andy. Taps conventionally work by driving a screw into a threaded space (with or without some kind of piston) to reduce the cross sectional area available for the water to flow through, down to zero. The tighter the compression, the smaller the space.

This 'vintage' diagram illustrates it nicely.

Taps pre-date volume controls by a very long time indeed - they were very highly established technology - so there was no reason to redesign them to tally with the concept of going anticlockwise to turn something down.

[TonyDuell]

I remember a water drain tap (on a car engine 40 years ago -- sorry!) that had to be screwed in to open it. It was made with a left hand thread so it worked the same way the tap in the bathroom -- anticlockwise to open.

I believe there were a few radios made (American?) where you turned the volume control clockwise to reduce the volume and ultimately open the on/off switch.

[kalee20]

Electric cookers you turn the knobs clockwise to raise the heat; gas coolers you turn anticlockwise to raise the heat. I think different origins establish different conventions, which occasionally clash.