Allen screws in the hub of the hook and lift the
hook off the hook shaft. To remove the bobbin
case from the hook assembly, loosen the hook gib
screws, lift off the gib, and then lift out the bobbin
Removing the Arm Shaft
When the arm shaft connection belt is
disconnected for any reason, the machine will be
completely out of time. Therefore, the needle
should be removed before removing the belt to
prevent damage. To remove the belt, slide it off
the lower belt pulley, loosen the screws in the
machine pulley, and remove the pulley and ball
bearing, which come out through the end of the
Replace the belt by reversing this procedure.
Remove the end play from the shaft by lightly
setting the setscrews and tapping the balance wheel
into position with the palm of the hand and then
securely setting the setscrews. Place the belt over
the upper belt pulley and line up the timing marks
on the lower belt pulley and on the bed of the
machine. While holding the lower belt pulley in
position, turn the balance wheel toward the
operators position until the thread take-up lever
is at its highest position, then slide the belt onto
the lower belt pulley. The arm shaft connection
belt and the lower belt pulley are illustrated with
the safety clutch in figure 9-32.
DO NOT TAMPER WITH THE
SAFETY CLUTCH. ITS TORQUE IS
PRESET AT THE FACTORY.
The hook saddle is equipped with an oil
reservoir (fig. 9-36), which contains oil to be
pumped to the bobbin case raceway. The flow of
this oil is controlled by a control valve screw
located just aft of the bobbin case opener in the
hook saddle. For more oil, turn the valve screw
clockwise; counterclockwise for less oil.
DO NOT ADJUST FLOW OF OIL
WITHOUT FIRST LOOSENING THE
LOCKING SCREW LOCATED ON THE
SIDE OF THE HOOK SADDLE JUST
ABOVE THE CAM SHAFT GEAR.
AFTER ADJUSTING THE CONTROL
VALVE SCREW FOR PROPER FLOW,
RETIGHTEN THE LOCKING SCREW.
SINGER SEWING MACHINE
143 W 2 AND 3
This type of machine is not as common as
those previously described, but it has unlimited
uses in the repair and maintenance of parachutes
and survival equipment.
The 143 W 2 is a high-speed sewing machine
that has an aluminum alloy vibrating needle bar
frame and a rotary hook. It is intended for
overseaming and zigzag stitching on fine and
general fabrics and lightweight leather. It has ball
bearings on the rear end of the arm shaft and
hook driving shaft. The needle bar has a
maximum throw of 3/16 inch, vibrating both sides
of a centerline.
The 143 W 3 sewing machine is similar to the
143 W 2 except that the needle has a maximum
throw of 5/16 inch.
The maximum speed recommended for
machine 143 W 2 is 3,500 stitches per minute, and
for machine 143 W 3, 3,000 stitches per minute,
the speeds depending on the material being sewn.
Needle and Thread
The needles for
sewing machines are
the 143 W 2 and 143 W 3
of class and variety 135 x 7;
the sizes from 7 to 24.
Left twist thread should be used on these
machines. To make a smooth even stitch with the
sewing machine, use good, firmly twisted and
smoothly finished thread. The thread should pass
freely through the eye of the needle.
Setting the Needle
Push the needle up in the needle bar as far as
it will go, with the LONG THREAD GROOVE
TO THE FRONT, and secure it firmly with the
setscrew. It may be necessary to turn the needle
slightly to the right or left for some threads if
stitches are missed.