Chandler 543 - Page 6

MECHANICS INSTRUCTIONS
TH R EA D LO CK TIMING AD JU ST MENT
\\'hen the Needle Bar
has ascen d ed to within
1/8 or 5/ 32 inch fro m
the hi ghest po int of
of the Needle Bar
stroke on comp le tion
of the last stroke of
the sewi ng cycle, the
thr ead shou ld be lo cked
by th e fo rward pr essure
of Plunger A against
PI ate B (Figu re 1A).
The Thr ead s houl d be
l ocked wh e n the m ac h-
ine
stops,
th e thread
br ea k when
is 1 ift ed.
other wi se
will not
the Clamp
FIGURE l A
FIGURE 1
C au t ion : Excessive pressure of th e P l unge r on li ght or w eak thre ad will
have a t ende n cy to frac tur e the thr ead causi ng excessive t hread br eakage.
To a dju st, loose n L oc k Nu t C (F igu re 2) and turn Adj usting Screw D in
or out the des ir ed amount. Be su re to tigh ten L ock Nut C secure ly.
FIGURE 2
N o te : Machi nes are
usually e quipped with
li ght Lo ck Spring for
use on light thread .
For h eavy th r eads us e
heavier Lo ck Spring
(See Plate 1 ).
On r esuming the first
st r oke of the n ew sew -
ing
cycle, the Thre ad
L ock must r elease the
thr ead some time befo re
the Ne edle Bar reache s
the l owest point of
the s t roke so that the
t hread is not he ld ti gh t
when the Take -up E
(F ig ur e 1) above s tarts
i ts r eturn u pward s t roke .
Br
acket F ( Fi g ure 12)
1s
provided with slots
so t hat the Tr ip Lock
Leve r may be re ta r ded
or adv an ce d for prope r
ti
ming .
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CHANDLER 4
From the library of: Superior Sewing Machine & Supply LLC