Years ago while working as a stonemason I taught myself how to forge and temper my chisels keeping them in top condition for the job. When I retired I got interested in making knives for the kitchen and for hunting.
Using my wood burning stove I managed to make some of these knives below but have recently built a proper forge using propane which really speeds up the heating process.
This knife above started out as an old leaf spring
this one below also started as a leaf spring...
These knives above started as old files and C clamps