EE was assisting in the installation of a new foot shaft on a CM.He was using a pry bar to hold the shaft in place while another EE was triyng to drive the shaft in using a hammer.A piece of metal broke off from the hammer or the shaft and struck the injured in the left forearm. (After seeing a surgeon the decision was made to leave the metal in his arm-Misc Mail 7/1/08 #3)