Singer 281-21 - MACHINE TIMING AND HOOK CLEARANCE; Timing the Sewing Hook; Setting Needle-Hook Clearance

TIMING THE MACHINE
Timing the machine consists of first adjusting the
radial position of sewing hook with relation to move
ment of
needle bar and needle thread take-up lever, to
make certain that loop of thread formed by needle will
be correctly taken by point of hook at proper time.
The check spring and feed
are then timed to syn
chronize their motions with needle and hook movement.
TIMING THE SEWING HOOK
Remove slide plate, throat plate, presser foot and
feed dog.
Turn machine pulley over toward operator until
needle bar reaches its lowest point and rises to posi
tion where LOWER TIMING MARK on needle bar is
level with bottom of lower needle bar bushing, as shown
in Fig. 23.
At
this position, point of sewing hook should be at
center of needle, as shown in inset, in Fig. 23.
Loosen two hook body screws shown and turn hook
on shaft as required to bring point of hook to center of
needle. See Fig. 24.
Make certain that hub of hook is against oil re
taining collar and tighten hook body screws.
Check clearance between needle and hook point,
in accordance with the following instructions.
SETTING THE CLEARANCE BETWEEN
NEEDLE AND HOOK POINT
Check to see that needle is properly seated in
needle bar and time sewing hook as previously in
structed.
Point of sewing hook should pass needle as closely
as possible without striking or deflecting needle.
A clearance of about the thickness of a piece of note
paper (approximately .005 inch), as shown in Fig. 25,
is sufficient.
EYE
HOOK
POINT
CLEARANCE
ABOVE EYE
HOOK POINT AT
CENTER OF
NEEDLE
LOWER TIMING
MARK LEVEL
WITH BOTTOM
OF LOWER
^ NEEDLE BAR
BUSHING
Fig. 23. Hook Point at Center of Needle
HOOK
BODY
SCREWS
Fig. 24. Hook Body Screws
OIL
RETAINING
COLLAR
NOTE-PAPER
FLAT OF
HOOK POINT
Fig. 25. Clearance Between Needle and Hook
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From the library of: Superior Sewing Machine & Supply LLC