First, welding began to replace riveting in ship-and plane-building (TIME. Dec. 15). Now cast steel is replacing forged steel, and in tanks it is replacing both riveted and welded armor plate.

In this video, the process of forging a katana sword from an engine gear wheel is showcased. The timeline of events includes: ...

This is the longest sword I have made; forging alone took about a week. It was one of my hardest projects. Dimensions - ...