The ornamental design for a tappingscrew, as shown and described.
FIG. 1 is a top plan view of the tapping screw;
FIG. 2 is a front elevation thereof;
FIG. 3 is a bottom plan view;
FIG. 4 is a right-side elevation thereof;
FIG. 5 is a rear elevation thereof;
FIG. 6 is a left-side elevation thereof;
FIG. 7 is a cross section taken along the line 7-7 in FIG. 1; and,
FIG. 8 is a perspective partially magnified reference view of the threaded portion of the screw. The portion is shown enlarged for ease of illustration.