The ornamental design for machine gripping finger, as shown and described.
FIG. 1 is a perspective view of the machine gripping finger embodying the new design;
FIG. 2 is a top view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a front view thereof; and,
FIG. 6 is a rear view thereof.
FIGS. 1-6 show features of a machine gripping finger in phantom lines. These features are shown for environmental purposes and do not form any part of the claimed design. Further, the phantom lines immediately adjacent the solid-line portions of the design form the boundary of the design, with the phantom lines forming no part of the claimed design.