Looks like part of a clock escapement, or the large circular part with the peg in it could locate into the teeth to change the drive direction 90 degrees. Paul
From experience during my study I saw similar tools which were used for regrinding seats of valves in the chemical industry. But they can be used for water taps as well it is a matter of having the proper diameters. As with many things today people buy a new tap or valve. Repairing is only for us the old guys.