C A Mitchell

Chips and shards are real. They occur because forging steel turns it into a crystal, and all crystals (even diamonds) have faults, which are weak lines in the crystal matrix of iron and carbon molecules. (The most fault-free forging is supposed to be the jet engine compressor blades in fighter aircraft -- 24 inch long faultlessly-pure crystals of steel! That keeps them from fracturing and flying apart at 30,000 RPM.)

Since we can't afford $20,000 hammers, ours have some faults. So how can hitting together any two forged, hardened, tempered things ever be safe? It can't. That is why only the cutting edges of cold chisels and pin drifts and other striking tools are hardened and tempered. The haft (the head or top) of the struck tool is left soft to deform (mushroom) well below the cracking threshold of the striking tool.

The man shown striking a peening hammer is just using the wrong tools. He can use the flat face of a forged hammer to strike a round peening dolly (e.g., a Dagger CP560) or a convex dowel drift (either of which, of course, have soft hafts). For most of us, the best (cheapest) solution is to use our brass or bronze hammers (for peening, use an 18 to 24 oz head) to strike the ball peen hammer. Both the brass and peen hammers should be stored WITH your struck tools.

By the way, peening is a fitting operation, so the miter gauge must be peened while in the grove. The commentator who thinks this a problem is wrong.

Remember, using a bronze or brass hammer means that you won't damage struck tools, you won't create sparks and you won't have to worry about high-velocity steel shrapnel. Afterall, it's supposed to be a shop, not a war zone.