The head diameter was perfect and the head is THICK. It was so thick that I am able to tighten a screw into place with the existing slot, mark the indexed location, cut a new slot and then dress it down to the action. If you are worried about cutting the slot I used a Vermont American 32 tooth/inch copeing saw blade. The thickness is perfect and the blade is about .250 tall and stiff. Does a perfect job, of the correct width, for a small investment. I use watch makers files for tiny screws but the copeing saw is great for a lot of mid sized screw slots.
bill
