The Collaborative International Dictionary
Grozing iron
Grozing iron \Gro"zing i"ron\
A tool with a hardened steel point, formerly used instead of a diamond for cutting glass.
(Plumbing) A tool for smoothing the solder joints of lead pipe.
--Knight.
Wiktionary
grozing iron
n. 1 a plumber's tool for soldering lead pipes 2 a tool used in making stained glass windows