The minimum length of thread engagement should be equal to twice
the diameter of the screw. The hole diameter, to ensure optimum performance,
should provide for 65% to 75% thread engagement.
Screw
Size
Hole
Diameter as
Cast Std. Taper
F
Hole
Dia.
as
Drilled
L
Length
of Thread
Engage-
ment
H
Boss
Dia.
Max.
J
Distance
to Edge
for no
Measurable
Distortion - Min.