Just for reference, Burrard gives decimal equivalents for the following vulgar fractions:

16/1 - 0.669"

16 - 0.662"

17/1 - 0.655"

17 - 0.649"

Below would be the vulgar fraction data from the German proof tables with values in mm:

16/1- 16,99mm

16- 16,81mm

17/1- 16,64mm

17- 16,48mm

Cheers,

Raimey
rse