Singer 620 - Timing the Hook

To Time the Hook
Sot noodle bar at correct height, and time the
needle-bar vibrating mechanism as instructed on
pages 7 and 8, Service Manual for Classes 600 and
603 Machines.
Insert a Size 18 needle up into the needle clamp.
Remove throat plate, bed slide, bobbin case, and
bottom cover. It is not necessary to remove the feed
dog to time the hook.
Adjust machine for straight stitching in center
needle position.
Turn hand wheel over toward operator until lower
timing mark is aligned with lower edge of needle-
bar bushing on UPWARD STROKE of needle bar. At
this position, point of hook should be at center of
needle as illustrated.
To adjust, loosen the two set screws in horizontal
bevel gear. While maintaining position of needle bar,
turn vertical bevel gear at hook-end of shaft until
point of hook is in correct position. Then tighten
the two bevel-gear set screws securely, making cer¬
tain that gears are correctly meshed without binding.
CAUTION: Hub of horizontal bevel gear should
not contact face of bushing.
Replace throat plate, slide plate, bobbin case,
and bottom cover.
VERTICAL BEVEL SETSCREWS HCRIZONTAL 3 EV EL
\ SEAR
GEAR HUB SHOULD
HOT CONTACT FACE
OF BUSHING
7