Why You Should Never Quench a Knife in Used Motor Oil (Blacksmith Warning !)

Описание: A Little Wisdom Helps You Become Smarter !

In the video, an elderly blacksmith quenches a freshly forged steel kitchen knife—still glowing red—into a bucket of used motor oil, sending steam and smoke into the air. This traditional hardening method, common in small workshops, aims to cool the blade rapidly for durability.

Key risks: Used oil releases toxic fumes when heated, risks fires (oil ignites at 200°C), and creates uneven cooling, leading to a brittle or soft blade.

Better method: Heat the blade to bright orange (800-850°C), quench in water (for high-carbon steel) or commercial quenching oil, then temper in an oven at 150-300°C. Always work outdoors with gloves, goggles, and fire safety gear.