Building a Heat-Treating Furnace by John Benjamin (DVD)
John Benjamin has been building firearms for many years. Some of the nation's most successful benchrest rifle barrels have been built by him.
Part of his secret is the fantastic heat-treating furnace he built. He shows and describes how it is built, and how it is used.
Barrels are heated in a vertical position, and gently brought to a stage of stillness evenly throughout their entire length. His furnace has been used over 300 times without any evidence of wear.