Singer 451k45 - TO SET CHECK-SPRING (Contd)

10. TO SET CHECK-SPRING (Cont'd)
Make certain that feed dog is below top surface of
throat plate and that presser foot is resting on throat
plate. Place complete assembly in machine so that
check-spring loop (at rest) is in "2 o'clock" position,
about 1/4 inch above thread pull-off V as shown in
Fig. 44.
HEIGHT VARIATIONS (FOR REVERSE FEED MACHINES)
Under certain conditions of tacking it may be nec
essary to set check-spring higher than it is otherwise
normally set.
TENSION
Tension of check-spring should be set so that when
machine is sewing 16 stitches per inch at 5000 R.P.M.,
spring will overthrow beyond the "5 o'clock" position
but not beyond the "6 o'clock" position. (See Fig. 44.)
To adjust tension, loosen screw Y, Fig. 45 and re
move entire assembly. Loosen set screw N, Fig. 43,
page 15 and, while holding regulator X, Fig. 43, turn
stud over slightly toward left to increase tension or
toward right to decrease tension. Tighten screw N,
Fig. 43, and replace assembly in machine with spring
at "2 o'clock" as shown in Fig. 44.
TENSION VARIATIONS
The required tension on check-spring may vary, de
pending upon the thread and material used. Heavier
thread and bulkier material require more tension to
ensure correct thread control.
TO REMOVE AND REPLACE FACE PLATE
REMOVAL
1. Remove the two screws Z2, Fig. 30, page 13 and
take-up guard N2, Fig. 30.
2. Remove two screws 02 and rotary take-up
V2, Fig. 45.
3. Loosen screw Y, Fig. 45 and remove needle thread
tension assembly.
4. Remove nine screws F, Fig. 45 and remove thread
guide I, tension threading guide M and face
plate P2, Fig. 45.
REPLACEMENT
1. Install face plate P2, guide M and guide I as
shown in Fig. 45, fastening them to machine cast
ing with nine screws F, Fig. 45.
2.
3.
4.
Replace take-up V2 and two screws Q2, Fig. 45.
Replace needle thread tension assembly and se
curely tighten set screw Y, Fig. 45.
Inspect check-spring setting as instructed on
page 15 and above.
5. Replace take-up guard N2, Fig. 30, page 13 and
securely tighten two screws Z2, Fig. 30.
16
Q2
2 o'clockI
^^>^5 O'CLOCKJ
u
6 0 CLOCK
^30938
Fig. 44. Setting the Check-Spring
P2
Fig. 45. Removing Face Plate
From the library of: Superior Sewing Machine & Supply LLC