Although transfer punches are commonly used to mark the locations of holes, they are not effective when used on rough surfaces, such as concrete floors and concrete-block walls. For those situations, I use punches made from HSS drill blanks, which are available from industrial supply companies. After creating the rough shape of the punch’s taper with a bench grinder, I chuck the blank in a drill. With both the drill and the grinder running, I place the blank on the grinder’s tool rest while grinding the final smooth taper and centered point, as shown in the drawing shown. Drill blanks are available in all drill sizes, and I have made several of these punches to match the clearance holes of the bolts I commonly use. Besides concrete, I have used these punches on wood and most metals and have found that they need only infrequent sharpening.
Elliot Eisenberg, Conyngham, PA