Just a short safety reminder to all...... On tools, chisels, etc. that are meant to be used as hand tools and struck with a hammer...... Only the end that is in contact with the work is hardened. That is why the end you strike with a hammer has softer metal split and over time, will bend back down the shaft, needing grinding to remove and dress up the hammer end from time to time.
Conversely, tool heads that are designed to be inserted in pneumatic tools such as hammer drills and jackhammers are hardened on both ends. DO NOT STRIKE THESE PNEUMATIC HAMMER HEADS WITH A HAMMER! Hammer heads are hardened, as well. When you hit a hardened surface with another hardened surface, shards of hardened steel can come off one or the other.
I had this happen once and had to have an eye doctor pull a steel sliver out of my left eye the following day. It was only 1/4" long, but it felt like a boulder. My hand chisel was old and the striking surface had been ground down and shortened over many years of use. So much so that the striking surface had gotten down to the hardened metal for the tip.
This same thing happened to a journeyman pipefitter I apprenticed for back in the late '60s. We were working on the 23rd floor of a 55 story building going up in downtown Houston. No walls, just bare concrete floors with holes for pipe chases, stairs and elevators yet to be installed. 22 degree cold air blowing through about 30 MPH. Typical winter work day for us.
He had several layers of clothes on. The metal shard went through them all and he couldn't pull it out with gloves on, so he called me over and told me to pull it out with my channel lock pliers. He pulled his coat and shirt back and I pulled it out...... There was just enough sticking out of his belly to get my pliers on. It turned out to be 3/4" long after I got it out and it punctured his stomach. So I drove him to the hospital for a tetanus shot and to be checked out. He healed up OK. And so did I.
Safety first,
Harry
