TM 10-3530-207-14
4-49. BUTTON SEWING MACHINE MAINTENANCE ADJUSTMENT PROCEDURES - continued.
i.
To time the looper.
(1)
With the needle bar set at correct height, as instructed in paragraph 4-49e, turn the machine
hand wheel, by hand, to bring the needle bar to the bottom of its LEFT HAND STROKE.
Continue to turn the machine-driving pulley until, as the needle bar rises, the TOP of the looper
point reaches the center of the needle.
(2)
With the TOP of the looper point at the center of the needle, the BOTTOM of the looper point
should be exactly at the top of the needle eye (2), on the left hand stroke of the needle bar.
(3)
If the BOTTOM of the looper point is not exactly at the top of the needle eye when the TOP of
the looper point is at the center of the needle, on the LEFT HAND STROKE of the needle bar,
make adjustment as follows'
(4)
Loosen the two set screws in the crank (1). Turn the looper shaft until the BOTTOM of the looper
point is exactly at the top of the needle eye when the TOP of the looper point is at the center of
the needle on the LEFT HAND STROKE of the needle bar and the needle bar has risen slightly
from its lowest position. Then securely tighten two set screws in crank (1).
NOTE
When the looper point is correctly set with relation to the needle on the LEFT HAND STROKE of
the needle bar, the looper point will be in proper relationship to the needle on the RIGHT HAND
STROKE of the needle bar.
4-115
