Major HIT-21 Instructions page 3

The HIT-21 is used to
locate and accurately drill
the inside cylinder hole for
a mortise lock when
retrofitting a single cylinder
to a double cylinder lock.
First remove the lock
faceplate and loosen the
cylinder retaining screw.
Next remove the outside
mortise cylinder and
replace with the HIT-21
drill guide.
Copyright 2016—Major Manufacturing