Vintage "Electro-Cal" 10 millionths measuring device.

[.RC.]

I have had this here for awhile, thought I might share some pictures if anyone is interested.

It is a dial test indicator that can measure to the 10 millionths of an inch range. ( 0.000254 mm) It is an unused device, supposedly a person over here was wanting to become a dealer for the Taper Micrometer Corp and was sent various devices that manufacturer sold, but I guess it went no where. (you can find taper micrometers on ebay still and they sell for high $$, they are not electronic)  The instructions were mostly glued together to the device and box when I got it, but one diagram sheet has 1963 dated on it.

The indicator has a ruby tip and the bit of the instructions I can read indicate the main uses it was designed for was for checking tolerances of gauge blocks by using it as a comparator.  You would put the indicator in a special stand.   Put your known reference standard gauge block under the indicator.  Then slip the block being tested under the gauge and measure the variance from the standard.

It was powered by mercury batteries, I guess because they held up their voltage well as they were discharged.  I had powered it by 5V.

Unfortunately the dial which is essentially a 100 microamp dial did not work so I bodged in an external russian made 100uA meter I got off ebay.

I had dreams of converting it to a digital display, but whether that will happen I do not know.   My current skill set is not capable of doing that.