Odd "dial key" on eBay. Looks kinda like a key but...

[timof5stars]

There's an odd item in the Collectibles|Locks & Keys group on eBay that resembles a key but is more likely some sort of dial caliper or similar tool:

http://tinyurl.com/dial-key

Anyone know what this was used for?

[Huw Eastwood]

It looks Indian circa 2005 to me- I don't believe that's an antique casting

[oldbiscuit]

That's a RPM guage. You zero it out and put the end on a rotating shaft and count the revolutions in one min. They were very common in the early 1900's. I still have one made by Starret that's probably not more than 15 years old that I still use on my old antique engines and belt driven equipment.

[wylk]

For long-term reference I'll add an image to this thread: