What is it?

[GordTopps]

Anyone any idea what this is?
I inherited it from my dad many years ago, guess I take after him inasmuch as I collect things (hate to throw anything away lol)

I think its some kind of early tachometer.
The end is a three sided taper, looks as though its meant to fit into a shallow centre drill hole. it came with two or three adaptors, rubber ended, one was a disc, so knowing the dia or circumference you could calculate the rpm.

I am supposing you set the two dots (zero the instrument) and then (depending on how fast the thing you you are measuring the rpm of) measure the set time (say 10 secs, 30 secs or 1 minute etc,) and then look at the indicator to see how many marks it has moved ( 0- 100 on the outer scale. If it has moved 80 divisions and you timed it over 1 minute it would be turning at 80 rpm.
Wonder if its worth anything on ebay?

Regards
Gordon

 

[Krown Kustoms]

That is exactly what it is.
I would keep it.
-B-
http://www.goantiques.com/detail,starrett-107-speed,602802.html

 

[cfellows]

It's a revolution counter which can be used as a tachometer. You set the counter to zero, place the pointed end into the center of a rotating shaft and then let it rotat for a measured amount of time. You can then calculate the RPM based on the number of turns and the amount of time you let it spin.

Chuck

 

[Richard1]

Chuck is right I have one exactly the same, it is still in working order and I use it more often than I every expected to. It seems to be quite accurate.

 

[Tin Falcon]

Now that you know what it is ,clean it up oil put it in your tool bock use as needed.
Tin