I have one of these and it's lots older than 1960. Have the instructions as well, but at the moment its location eludes me. As soon as found will scan and send.
As far as can remember set all the dials to zero by loosening centre screw slightly. Hold it against centre of item, e.g. item in chuck as the chuck is spinning. As it starts to spin the dials will rotate and the count will increment. Stop after say 15 seconds, read the value of the dials, multiply by four to get rpm.
Colin
Colin