Singer 620 - Bight-Amplitude and Pattern Selector; Bight-Amplitude and Pattern Selector Removal and Replacement

NOTE: The following instructions apply goneraily'to Class
620, 625, 626 and 628 Machines. As indicated on page 13,
however. Class 628 Machines must use the Sight-Amplitude
Selector in lieu of a Release Mechanism in order to neu¬
tralize the particular zig-zag stitch pattern provided by
the replaceable Fashion Disc utilized. Accordingly, the
section on page 20 dealing with Bight-Amplitude Adjust¬
ments will be particularly applicable to users of Class
628 Machines.
Removal and Replacement
Remove arm top cover, face plate, and control
panel.
Set stitch-pattern selectors at “A” — “K”.
Remove driving-arm spring.
Remove bight-lever screw from bracket, and re¬
move bight lever.
Loosen bight-amplitude set-screw and remove
entire cam stack assembly.
Remove bight-amplitude and pattern selector.
Replace pattern selector in the reverse order of
its removal.
Observe the following:
Assemble cam stack as a complete unit. Upper
eccentric half of worm wheel shaft should be turned
toward hand-wheel-end of machine, as shown.
Make certain that driving-arm ball-pivot is en¬
gaged with pattern selector.
Set mesh between worm of arm shaft and worm
wheel of pattern-selector by turning bight-amplitude
shaft clockwise so that there is no binding and a
minimum amount of backlash.
Tighten bight-amplitude set screw.
Replace driving-arm spring
Replace bight lever and fasten with set screw.
Adjust machine as instructed below and on fol¬
lowing page.
18