Democratic Sentinel, Volume 16, Number 18, Rensselaer, Jasper County, 20 May 1892 — To Harden Tools. [ARTICLE]

To Harden Tools.

It is said that engravers in Germany harden their tools in sealing wax. The tool is heated to whiteness and plunged into the wax, withdrawn after an instant, and plunged in again, the process being repeated until the steel is toe cold to enter the wax. The steel is said to become after this process almost as hard as the diamond.