I am completing a magneto tester similar to the St Louis Electrical Works and that described by Tom Carnegie. Doing the background search on magneto output I found the following from 1916 American Chauffeur. The text describes a pre 1914 518 inch magneto producing 3 to 5 AAC and a post 1914 314 inch magneto producing 5.5 to 8 AAC. Any suggestions, opinions, or comments about what a 518 or 314 inch magneto may be?
518 is probably 5/8" and 314 probably is 3/4", reffering to the magnet thickness.
Ken think you are correct. The type setter for the 1916 American Chauffeur miss read the fractions. The hand written quotient was interpreted to be a 1 and not /. Thanks