The ornamental design for a face for a timepiece, as shown and described.
FIG. 1 is a front view of the timepiece face indicating a time, showing our new design; and,
FIG. 2 is a front view of a timepiece face incorporated in a wrist watch case, showing the environment in which the design is used, and showing a time.
The broken line showing of a watch is for illustrative purposes only and forms no part of the claimed design.
The face for a timepiece is flat with rear edges being plain and unornamented.