The ornamental design for a serratedcuttingedge for a knife, as shown and described.
FIG. 1 is a perspective view of the serrated cutting edge for a knife, showing our new design;
FIG. 2 is a right side elevation view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a bottom view thereof.
The broken lines depict environmental structure (e.g., the rest of a knife and blade that the serrated cutting edge design would be applied to) and do not form a part of the claim.