This month's items are caulking chisels. Plumbers use them to pack oakum between pipes, which is why the edge is curved (and not sharp). The flat end of the tool is placed between two attached pipes. To pack the oakum, simply tap on the blunt end of the tool. Numbers 1 and 2 (left) are used to pack pipes that might be awkward to reach (overhead, for example). To see how they're used, click here.