Forge a knife blade from a car spring
I helped my friend to change springs on his car, so I kept the broken spring as forging material.
The carbon content of spring steel is aroundd 0.6 to 0.8% which works well for hardening - so lets forge a knife!
I cut out a ~10cm long piece from the car spring.
I use the induction heater to straight it out and flatten it a little.
It is not possible to heat too thin goods with the induction heater. This was how far I got until it did not heat up enough.
So I fired up the gas forge and continued there.
Now it is even thinner.
I forged the tang and began shaping the blade. Now I'm done with forging, the rest is more of an exercise in grinding...
Shape the knife with the belt grinder.
Use a jig to grind the edge with a ~8 degrees angle.
Polish the grinded surface.
The result
What remains is to normalize the steel before quenching it in oil followed by tempering to reduce the brittleness a bit. I'll wait on these steps until I have a few more knife blades to do at the same time. I'm also a little afraid that I ground the tip too thin so that it will crack during curing. We'll see.
This was my first attempt and I was probably more eager to test than actually get it right. For the next knife blade, I will have a clearer heel on the blade and possibly a completely different blade shape.
It was fun and now I know I have a method for all the necessary steps I need to make knives.
