Do you remember whether the tool was for regulators as
well as points-n-plugs?




The second line on mine reads "Point aligning tool"; and after a few more
attempts at guessing numbers that were mostly worn away, I found the correct
patent number: 2283789.

You can look it up he

http://patft1.uspto.gov/netahtml/PTO/srchnum.htm

....where it's described as a "Distributor adjusting tool", patented in 1942.
After you search on the number, click on "images", you might have to refresh
the pages a few times, I always have trouble on that site with them not
fully loading.


Rob