: Using a magnet is a standard DIY tool; once the steel stops being attracted to the magnet, it is at roughly 1,414°F. You should then heat it slightly further to reach the required quenching temperature for your specific steel.
: For many high-carbon steels like 1095 or O1, holding the blade at temperature ("soaking") for 10 to 30 minutes ensures uniform heating through the entire cross-section. Quenching Oil Temperature : Using a magnet is a standard DIY
The oil itself must be preheated to work effectively. Cold oil is more viscous and may cool the metal too slowly or unevenly. Heat Treating Knives : 7 Steps - Instructables it is at roughly 1