Hard Alloy
It is claimed that if an alloy is made from 4 copper, 7 zinc, and 1 tin, it will resist all attempts at turning; but if petroleum is used freely the alloy will yield at once to the tools. See BRASS; SPECULUM METAL.
Twelve hundred entries from the golden age of cast metal — how bells are founded, why brass is not bronze, what a cupola melts and a core withstands — by Simpson Bolland, the trade's great teacher.
It is claimed that if an alloy is made from 4 copper, 7 zinc, and 1 tin, it will resist all attempts at turning; but if petroleum is used freely the alloy will yield at once to the tools. See BRASS; SPECULUM METAL.