In article ,
notbob wrote:

On 2010-11-05, wrote:

In a european or american (ISO/ANSI) set, a 12mm might also be
missing, as it is only used in JIS standard. American (ANSI/ISO) sets
don't need a 17mm or a 19mm either.

I don't know what reference library fantasyland YOU are living in, but
having used metric sized wrench sets professionally for about 35 yrs,
I can certainly attest to the fact that 9, 12, and 17mm fasterners do
indeed exist and are found on real actual mechanical devices requiring
said wrench sizes.

nb

Clare is a Canadian mechanic. The Craftsman metric socket set I bought
from Sears 37 years ago includes 9, 10, 12, 13, 14, 15, 17, and 19. They
all have grease in them, so I guess I've used them all.