A template for use with an instrument for penetrating an uncut irregular surface through a hole in said uncut irregular surface, said hole being located at a desired location on said uncut irregular surface, said template comprising:a body including a custom surface shaped as a negative impression of the uncut irregular surface to conform to the uncut irregular surface, the body having a receiving section；a removable portion configured to be arranged in the receiving section；a removable guideway arranged at the removable portion and having a first end positioned to open onto said desired location when said body is placed in conforming contact with said uncut irregular surface, wherein the removable guideway comprises an inner piece and an outer piece, and wherein the outer piece includes an outer surface configured to engage an inner surface of the removable portion；means for securing said removable portion to said body； andthe inner piece configured as a stop for limiting a depth of penetration of said instrument into said hole.
