Classic cars forum & vehicle restoration.

[john-saab]

I have several gauges sitting around and i would like to know what they are for.
1st is this clock..it's 12v and very 1930's looking. It has no identifying marks but has a hand changer at the 8 o'clock position and a small narrow window (so it can be illuminated?) from 11-5 o'clock, the dial is a creamy off white colour..


No 2 is a pressure gauge made by A.I.R.C of Morden Surrey..it gauges pressure from -10 lb/IN2 to + 10 lb/IN2


3rd isn't really a gauge..it's mor a measuring instrument made by Sutra Paris..it's called a "Dead Beat" and i'm guessing it's a type of Tachograph but it measures 8V and 120V..it has R:230 and R:3550 also on the face..

4th is a clip on ammeter..clip the hook onto the king lead and it measures the charge amps..made by A.C.Withnell Ltd Ashford Middx..i would like to know more about the company.


Last is not automotive at all..unless early cars had them fitted...it's a gradient meter and it's dated patent number 21517 1910..made by Tapley & Co, Totton, Southampton. i think that the gradients are too shallow for it to be for an aeroplane..It's very heavy..another reason i don't think it's for an aeroplane, could it be for a train?


Again ideas and suggestions much appreciated.
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Rust Junky & oil addict.

[john-saab]

And as if by magic i have found a link to the gradient meter..apparently they were fitted to a pre-war Rolls Royce according to THIS auction house..can anyone confirm?
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Rust Junky & oil addict.

[MVPeters]

Interesting collection.

No. 3 is a voltmeter - I have an almost identical one (somewhere!) - red case & I don't know the manufacturer - if I ever find it again I'll let you know.

Put one 'spike' on a + terminal & the flying lead to earth - it assumes a negative earth but works either way.
I'm guessing the R: numbers are internal resistance values to get the range into either 8V or 120V. (I think mine reads up to 6V or 24V).
Probably from a mainland European country - 6volt car or 120volt mains electric.

Maybe "Dead Beat" is a poor translation of "Dead Battery" !

No. 4 - I'm no electrician, but I thought clip-on (inductive?) ammeters only worked on AC circuits. I'd like to know otherwise because I'd like to use one to measure motor current draw on a 600V DC-powered trollley car/tram. I haven't been able to borrow one to test this.

I'm also no aeronaut, but No. 2 could be a "Manifold Pressure Gauge" from an aircraft.
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Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[MVPeters]

and, of course, after just a few minutes research, I discovered that (some) clip-on ammeters DO work on DC circuits! So ignore my last comment.

I was told quite definitely that they don't by a 'licensed' electrician, which just goes to show that you shouldn't take every authoritative statement unquestioned.
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Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[Phil - Nottingham]

I have couple of modern clip on ammeters I use for testing on cars
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Rover P2
Rover P4
Rover P5 & P5B
Land Rover S2 & S3
Morris Mini Traveller Mk2

[mikeC]

The Gradient Meter was, indeed, a bolt-on accessory for early cars. Yours looks to be mid 1920s. They were a typical gimmicky accessory on pre First War cars, and obviously they tended to feature on the more expensive motors, like Rolls Royce.
Tapley produced a light-weight one in the the 1950s, similar to their Brake Meter - my father had both fitted to his Lagonda just for fun

[Jim.Walker]

For some reason, perhaps better known to the Gremlins (or perhaps a computer anorak) the pictures are not available to me.
I have used clip on ammeters specially made for automotive fault finding. I gave up though, when I found out any magnetism, which is what they sense to work, picked up from other nearby electrical circuits or permanent magnet electric motors etc. could give wildly wrong readings. Don't rely on them too much.
Of course permanent magnet motors on motor vehicles are a relatively new thing. Permanent magnets of twenty years ago have no comparison with the magnetic power of modern Neo magnets.
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Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[exbmc]

Like MVP, I also have one of the little voltmeters, and I don't know where it is! My late father in law gave it to me, many years ago. It has a reddish-brown case, and is bakelite I think. The lead and probes are the same, but I can't recall the scales.
If the pressure gauge is aircraft, it will be early aviation. Manf pressure gauges, are usually marked in Hg and go up to about 35.