Disconnect the spark plug wire or remove the battery
Drain the fuel or tip the mower only as recommended by the manufacturer
Wear heavy gloves and safety glasses
Mark the blade’s orientation before removal
Remove the blade with the correct wrench or socket
Secure the blade in a vise
Clean off grass, dirt, and rust
Inspect the blade for cracks, bends, or heavy damage
Replace the blade if it is cracked or badly worn
Use a file, bench grinder, or angle grinder to sharpen the cutting edge
Keep the original bevel angle
Sharpen both ends evenly
Remove only a small amount of metal
Check that both sides are balanced
Reinstall the blade in the correct direction
Tighten the bolt to the manufacturer’s torque specification
Reconnect the spark plug wire or battery
Test the mower briefly for smooth operation