2. GRINDING, HARDENING & TEMPERING

After forging, the focus turns to grinding and sharpening the edge. The rest of the axe head is left just as it is. After coarse grinding, the edge is hardened by heating it to 820°C and then rapidly cooling it in water. The hardening makes the steel much harder, but also rather brittle.

To remove the stresses in the steel caused by the forging and hardening, the steel needs to be tempered, which involves keeping the axe heads in an oven at 195°C for 60 minutes. The hardness of the steel depends chiefly on its carbon content, but also on the tempering temperature.

Oil or lead can be used as an alternative to water for cooling. However, Gränsfors Bruk only use water since that is the most eco-friendly option.