Had this givin to me yesterday. Anyone seen one of these? A real old Steward Warner tach in x hundreds. about 3 inches across. Thinking of putting it in my 28 rpu even if it doesn't work. Cool looking. Anybody have a clue what it was used in?
That isn't a tach from a car. It is a hand-held tool used for checking machinery. That's why it has two scales, so that it can read rotating in either direction. It should have a conical rubber tip that you hold against a rotating shaft.
I realy didn't think it was from a car. Checking machinery? It does have the rubber tip on on it. Do you know what era?
Does it work? You could keep it in the glove box and use it to check the speed of your fan belt, etc.. Amaze your friends!
They can also be used with a rubber wheel of a calculated size to measure surface speed, then shaft speed can be determined if the shaft end is not accessible.