general query

[padmarsh]

I have just joined here after browsing for a little while and I am hoping some one can help me with identifying the attached instrument and also what it does. It is in a battered but fitted case and it was in a tool auction with some tools I wanted. I will probably sell it eventually unless it is useful to me in what I do.
Regards, Peter.

[mklotz]

I'm guessing it's a mechanical tachometer.

Does the pyramidal point rotate and is it connected to a worm inside the body of the instrument that rotates with it ?

If that's true, it probably works as follows...

Place the pyramidal point against the center of some rotating body. Then squeezing the handles causes the gear toothed wheel with the calibrations to rotate. Let the instrument rotate for a measured period of time. Reading the dials will then show the number of revolutions that occurred in that period of time - exactly what a tachometer is meant to measure.

The smaller dial counts full rotations of the large dial.

[padmarsh]

Many thanks for this, Marv, yes the central pivot does rotate.At least I have a starting point to go on . I will try it out in the shed.
Regards, Peter.

[mklotz]

Many thanks for this, Marv, yes the central pivot does rotate.At least I have a starting point to go on . I will try it out in the shed.
Regards, Peter.

Please report on the outcome of your trial; I'm curious to see if I guessed correctly.

[padmarsh]

Sorry for the late reply, I probably won't get to it until the weekend. Any ideas about age? I haven't found anything like it on the internet yet. Looks at least vintage , with the fitted ,velvet lined case , but no makers name or other markings.
Regards, Peter.

[mklotz]

Sorry for the late reply, I probably won't get to it until the weekend. Any ideas about age? I haven't found anything like it on the internet yet. Looks at least vintage , with the fitted ,velvet lined case , but no makers name or other markings.

I did a search-by-image on Google images, hoping for something similar but only got pictures of wrist watches and references to this thread. The more common Starrett style mechanical tach is a very old design so, if this predates that, it's either very early or else a design meant to skate around patented designs, which I presume the Starrett is.

[Frank S]

I did a search-by-image on Google images, hoping for something similar but only got pictures of wrist watches and references to this thread. The more common Starrett style mechanical tach is a very old design so, if this predates that, it's either very early or else a design meant to skate around patented designs, which I presume the Starrett is.

I was doing a search as well because I used to have the Starrett tach as you mentioned the Starrett design dates back to 1897. I did find other designs of the mechanical rpm speed indicator or tachometer but none exactly like the one in the OP.
form my money I would not attempt to use it, but rather build a nice velvet lined wooden enclosure for it with a glass view window and put it up somewhere I'm betting that it is quite rare

[padmarsh]

Not sure what to do now. I might leave using it atm until I research a bit more . There are some overseas auction houses [ I am in Australia and there is not too much here] that specialise in engineering tools etc who may be able to help with age etc. It is currently in a velvet lined wooden fitted case with the outer covering a bit battered but otherwise good condition. Will report back when I know more. I agree with Marv about what it is, but it gives me a starting point for further enquiries . It may be a bit too old and rare to muck around with too much.
Regards, Peter.