Tap Drill Chart

What size holes to draw for fasteners.

Body/clearance: draw .006"/.15mm (minimum) to .015"/.4mm (generous) over nominal diameter fastener clearance for Q3 holes

Tap pilot holes: see the waterjet column in the chart - a compromise btw. 50-70% thread factoring waterjet taper. In general raw waterjet holes are acceptable as tap pilot holes for fasteners #8 or M4 or larger. For smaller fasteners, tap pilot holes should be waterjet cut .01" undersize and drilled to size.

For thread-forming / chipless taps, in general don't use raw waterjet-cut holes - these taps require a more precise pilot hole, and besides are ordinarily used only in CNC machining where the holes are drilled as needed in the same setup.

Work in progress: chart