HomelessjOe
Sperm Oil Is found in a reservoir located in the head of the Sperm whale.
In past ceturies it was the prefered fuel for oil lamps.[By the way,I was of the understanding that the Sperm Whale was a protected species!!].
Sperm Oil is an excellent oil for quenching screw heads/pins during the tempering process. Because Sperm Oil dose not contain the rust inhibitors found in most modern oils the bright purples & blue oxides seen during the tempering process are retained after quenching.
The resulting bright blues and purples seen on the pins and screws of best British Guns are a result of Quenching in oil free from rust inhibitors.
