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[Scalyback]

[center]






Maybe they are also known as clocks, because Smith's biggest business was producing clocks!

[Leon Novello]

I would call it a clock; chronometers are usually used to determine longitude at sea, or for very accurate time keeping. Verbum sapienti satis est, a word to the wise. Get somebody to hold the camera, I was getting nauseous watching that video.

[simon]

Acme of instrumentation IMHO. Smiths bought the patent from Jaeger in the 1920s? and produced an excellent quality product until the costs of manufacture became prohibitive in the 1960's. They are an exquisite piece of work inside and are not to be pulled down by anyone without suitable horological expertise. A friend has a very early Jaeger version from the First War era on his shelf and it still works perfectly.

[Scalyback]

Great, I did my best. I am on my own here until the 25th!



and they are incredibly accurate devices.

[1950s Bulleteer]

Did you have the bike on rollers to shoot this video?

[Scalyback]

er, no...



it was on the centre stand, with the back end in space over a downwards ramp!



I don't intend to do it again, just a one off!

[wilf]

That sure is a nice steady reading. Does anyone know if either of our hosts MPH speedos are as steady/accurate. (Part nos. 92576 and 92546)

[Scalyback]

They are very steady. Copied this from another site...

"The chronometric instrument was developed in France for aircraft use during the first world war. The rationale for using such a complex design lies in its ability to produce an absolutely precise speed indication. This accuracy (which the early day instruments couldn't match) made it a prime favorite for aircraft and racing cars where the RPM range is vital for performance and safety."



They did RPM as well as MPH/KPH.

Link to article TICKY-TOCKY LITTLE BOXES

[simon]

No sorry Wilf the modern equivalent its only a skin deep copy. The mechanism inside is a common but rather crude magnetic movement which gives an a reading that can vary hugely according to the age, cleanliness and quality of the manufacture. Better than nothing and reasonably accurate at one point but nothing like a crono. When I was a lad we had old Riley 9's and they had the Jaeger versions. Nothing like watching the gauges click round. I've got a metric one on the shelf for a project yet to be conceived and run one on the 350 Bitsa. They were relatively cheap secondhand for a while but the news has got out there and prices have spiralled.

[Adrian]

Simon,



check ebay UK, someone has a 1938 chronometric speedo up for £300.00 shock horror! Hope nobody bites at that price.



An alternative - though again very pricey - is to go for one of the digital Smiths replicas (both magnetic and chronometric instruments) offered by an off-shoot of the original company.



http://www.puca.co/news.html



The digital odometers might not look quite right to some, but the chronometric replicas can be set to copy the jerky movement of the originals!



Here's one of their grey-face rev counters sort of paired to an Electra-X type speedo for my next proj, I may have to get one of their speedos to match.







A.