I needed to make a 6" hole through a poured concrete foundation in my basement. I got a nice new makita hammer drill masonary bit for my drill and found out how ugly it could be. Forget that. A real masonary drill costs too much and I didn't want to rent one so I thought what about my hand held air chisel. It is a cheap HF job I used a few times for cutting panels or drum tops off . Thats about all I thought it was good for. Then I tried it on the 15 year old cement. Wow does it cut. Of course it is still a 6 pack job and one hell of a mess but its a lot easier to use than a drill. Strangely it doesn't even dull the Chinese cheapo tips at all. What's best is that there is no need to lean hard on the gun and it doesn't take a monster air compressor either. Just put a little pressure on it and let the spring do the work. I bet I paid a whole $15 for the thing. Incredible. The only thing I wish I had was a longer set of Ajax chisels.