Gun Port Drill Jig directions (Cont'd):

"The hole is central to the clamp's width, and 9/32" (.281") from the heel end." In use, a port lid is placed in the slot with the ears and hinges in the recessed slots in the bottom of the main slot. The nylon clamp is placed into the slot, the screw is inserted into the clamp and secured.

The block is now placed on one side and an ear drilled.

The block is now inverted and the other ear drilled."