The ornamental design for a tip for a grindingwheel, as shown and described.
FIG. 1 is the prespective view of the tip for a grinding wheel of the invention;
FIG. 2 is a front view thereof (the rear view thereof is a mirror image of this);
FIG. 3 is a left side view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a front view of the invention attached to the shank of a grinding wheel. All of the grinding tips except one are rendered in broken lines, as well as all parts of the shank of the grinding wheel.
The broken line showing of environmental structure, directional placement, and replications of the claimed design are for illustrative purposes only and form no part of the claimed design.