They are not over hardened, but either not tempered or under tempered.
First it would be fully hardened to convert as much of the steel as possible to Martensite, tempered is very brittle, then the tempering decreases the size of the shard like Martensite structures to make it both softer and tougher. The temperature, number and duration of temper cycle or cycles will determine final hardness and toughness
Not so much a language purist, just want people to understand metal heat treatment
In any event, I will not bee ordering any reamers from them after the ops horror story. I have discovered that when I have a pleasant experience dealing with a company's employee everything will work out well. When I deal with an angry employee it is usually the sign that things are not well at that company and there will be more problems than anything else.
