For my next installment in the beginners series I decided to do the fast and loose approach to heat treating 5160 & SUP9 (which are the same thing).
This method will be suitable for people who ALREADY have an Oxy/LP Oxy/Acetylene rig. This will work for smaller knives with the Bunnings brand Bernzomatic torches. It is far cheaper to buy the parts for a gas forge that will do a much better job of your heat treating than it ywould be to go out and buy a $400 cutting torch set and rent an Oxygen bottle. This is by no means a definitive guide to the heat treating of spring steel for knives... just a place to start.

Heat past non magnetic (Ideally 830 Celcius) and hold for 2-5minutes

Quench blade first into oil (conola, vegetable but not motor oil)

When cooled to room temperature grind surface back to expose bright steel

Test bright steel at edge, if hardened correctly it should be "glassy" a regular file should have a hard time marking it

Put in kitchen oven on 205 Degrees Celcius for 2 hours, then let cool outside of the oven to room temperature. Then repeat. Steel must be tempered twice.

This should result in a blade that has a degree of toughness and hardness suitable for use as a knife.

Steel = SUP9 x 6mm x 70mm x 1200mm
https://www.artisansupplies.com.au/product/sup9-high-chromium-spring-steel-6-x-70-x-1200-mm/

Tongs: Wayne Saunders Knife makers tongs
https://www.artisansupplies.com.au/product/21247/

Thermocouple reader : (ignore the photo it is different)
https://www.artisansupplies.com.au/product/digital-thermometers/

Thermocouple:
https://www.artisansupplies.com.au/product/high-temperature-stainless-steel-braided-thermocouple/