Old timer told me I was grinding too hot and he was right

I had a guy in his 70s watch me work a knife blank at a hammer-in last month. He just said "you're burning the steel, son" and walked off. I was grinding with a fresh 36 grit belt and pushing hard to shape it fast. After I cooled it off I could see the blue oxidation lines running down the edge. That steel was toast. I backed down to a 60 grit and started dipping in water every 3 seconds. The finish came out cleaner and I didn't lose any temper. Has anyone else had to slow down their grinding to get better results?

2 comments

2 Comments

morgan31620d ago

Read somewhere that Japanese sword makers dip their blades in water constantly while grinding, sometimes after every pass. Seems like the old timers figured that out a long time ago.

rowan_butler9320d ago

Yeah but come on @morgan316, I mean dipping it after every single pass? That seems a bit much. I get that heat buildup is a concern when you're grinding hardened steel (it can mess with the temper if you're not careful), but I've seen guys just use a slow wheel speed and light pressure and they do fine. Plus those old Japanese smiths were working with much simpler steels than what we have now, so maybe they had to be extra cautious. Not saying they didn't know what they were doing, but I bet there's a bit of romanticizing going on there too.