(a) The pattern number of every casting in plain figures of larger size
than the dimension figures.
(b) The material of which the parts are made, using symbols as follows:
C.I.--Cast iron. W.I.--Wrought iron. M.S.--Machinery steel.
H.S.--Hammered steel. Bs.--Brass. Bbt.--Babbitt. Bz.--Bronze.
C.R.S.--Cold rolled steel.
Other materials write full name.
(c) Finished surfaces will be indicated by “f” written on the line or
surface to be finished. When not so marked it is understood that the
part is to be left black or rough. In cases where finish might be
presumed but not required, follow the figured dimensions by the word
“cast,” if a casting, and “rough,” if a forging.