The ornamental design for a hammer implement head, substantially as shown and described.
FIG. 1 is a side elevation view of a hammer implement head showing my new
design, it being understood that the opposite side is a mirror image
thereof;
FIG. 2 is an elevation view as seen from the left of FIG. 1;
FIG. 3 is a top plan view of FIG. 1, it being understood that the bottom is
a mirror image of the top shown; and
FIG. 4 is an elevation view as seen from the right of FIG. 1.