At least use an old hacksaw blade for a nicker. Most are only hard on the teeth edge,but they still have better wear resistance than ordinary mild steel. You can get all hard ones,but they'd have to be special ordered. Then,there is the problem of drilling a hole. You'd have to have a carbide bit,and know how to keep from popping the blade in half.
Hardened nail is o.k.,but are they only surface hardened? Keep a hardened surface for the cutting edge.