Heat treating a knife blade with a propane forge, a magnet and a can of canola oil
Normalize three times: heat to just past non-magnetic (test with a magnet on a stick), air cool to black each time. This refines grain.
Harden: heat evenly to non-magnetic plus a shade brighter, quench point-first in canola oil preheated to about 130°F (warm oil is thinner and quenches faster). 1084 and 1095 like fast oil; 5160 and 80CrV2 are forgiving in canola; O1 and A2 want slower oil or plate quench.
Test: a file should skate off the edge.
Temper immediately, twice, 2 hours each: 400°F in the kitchen oven gives a straw color and a hard edge for a kitchen knife; 450°F for a chopper you will beat on.
If it warps, straighten during the first temper cycle while warm, clamped to a flat bar. Do not try to straighten a hardened, untempered blade; it snaps.
#heat-treat#knife#quench#temper#1084#blacksmithing
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The embedded video is clearer than the official service manual, which is a little embarrassing for the manufacturer.
I did the same repair last month and your step 3 is where I got stuck. Wish I had this then.
Unplug it. Always. Takes two seconds and the worst case otherwise is a trip to the ER.
Followed along, got it done in about twice the time quoted, but it is done and it works.
Glad it helped.