Installation Guide

Drill and tap sizing chart

DRILL AND TAP SIZING CHART Table of drill and tap selections necessary to drill and tap holes for mounting holding block to strut or stern tube.
SCREW SIZE	TAP DRILL SIZE	TAP SIZE
5/16 X 18	17/64 or F or I – .257 – .272	5/16 X 18
3/8	5/16 or P – .312 – .323	3/8 X 16
STEP 1: Use regular starter tap. STEP 2: For shallow holes, use a bottoming tap to complete threads to bottom of drill hole.