The ornamental design for a gatheringtoolhead, as shown and described.
FIG. 1 is a front view of the gathering tool head;
FIG. 2 is a left side view of the gathering tool head; and
FIG. 3 is a rear view of the gathering tool head;
FIG. 4 is a perspective view of the gathering tool head;
FIG. 5 is a right side view of the gathering tool head;
FIG. 6 is a top view of the gathering tool head; and,
FIG. 7 is a bottom view of the gathering tool head.
The broken line showing of structural lines is included for the purpose of illustrating non-claimed subject matter and forms no part of the claimed design.