The ornamental design for a cuttinginsert, as shown and described.
FIG. 1 is a perspective view of a cutting insert showing our new design;
FIG. 2 is a top plan view thereof; and,
FIG. 3 is a front elevational view thereof; a right side view being identical to the front elevational view; a left side view being identical to the front elevational view; and a rear elevational view being identical to the front elevational view.
The broken lines illustrate environmental subject matter only and form no part of the claimed design. Surface shading lines form no part of the claimed design.