David and Kees,
I purposely kept my hammering fairly light. If you look at the pictures I took of the back side of the test specimen of 1095 I posted on Woodwork Forums you can see quite clearly that the surface wasn't dented. However the distortion did extend all of the way through the plate, I wanted to show that and that's why I photographed the back side of the test sample. Heavier impact is a future study.