Rotating Hook - Singer 250 Series Service Manual

II Rotating Hook
Removal:
1) Remove
D
andD
2)
Remove needle. p r esser fool. open bed sli de plale and remove lhroal p lale .
3)
Lill up cushion spring A and push il lo lhe righl. Remove bobbin case. Aepos1llon cushion spring .
4)
Remove bolh screws B and remove feed dog
C.
5)
Remove bolh screws D and lhe bobbin case posilion brackel E.
6)
Loosen screw W lo remove lension on bell W1.
7) Loosen bolh screws F.
8)
Remove rolaling hoo~ G . pulley H and bell W1 .
9) II necessary. remove eccenlric bushing J by firsl loosening sel screw K.
Caution on Reassembly:
a) Assemble lhe eccenlric bushing J wilh lhe indicalor L, showing posilion of eccenlr ici ly. loward~-
lhe lefl as shown in lhe skelch . Aolale il lo adjusl dislance of needle lrom hook poinl.
b) Bell W1 should be assembled logelher wilh pulley
H.
C) Press rolaling hook G downwards and pulley H upwards prior lo lightening lhe lwo screws F.
Nolt: : Before doing lhe adjuslmenl of lhis group. check bell lension adjuslmenl as ·
inE!)
Nee<Jle
Bar heigh! adjuslmenl as ,, . . . . cenleri ng of needle bar as
inD
and sideways selling of needle
bar as in
m
andm .
Adjustment of hook timing:
Check :
1)
Sel needle posilion seleclor lever on cenler needle posilion and sl1lch widlh seleclo r lever on
slraighl slilch.
2)
Place on No.
18
needle in needle clamp .
31 Remove lhroal plale .
4)
Turn handwheel unlil lower liming mark on need l e bar 1s aligned w1lh low<!r end of 11eedle bar
bush ing on lhe upward slroke of needle bar .
5)
Under lhese cond ilions. hook poinl N should be in lhe cenler beh ind lhe needle as shown in
skelch .
Selling:
Loosen bolh screws F, lurn hook G lo lhe correcl posilion all lhe while relaoning needle bar in lhe
posilion ind1caled above under check . Then . wilhoul d1slurbing lhe sell 1 nq . press down on hook G
whil e pressing up on pulley H and lighlen bolh screws F.
Adjustment of hook point to needle distance:
Check :
1)
Place needle posilion seleclor fever on cenler needle posi11on and slilch widlh seleclor lever on
Slra ighl slilch.
2>
Remove presser fool .
31 Remove lhroal plale .
4)
Remove bobb in case.
5)
Remove feed dog C.
6l Place a No . 18 needle in needle clamp .
71
Turn hand wheel unl1' hook poinl i s in lhe cenler behind needle.
8)
The dislance belween hook poinl and No.
18
needle should be
0
lo
0.05
mm.
(.000- .002) .
Selling:
11
Loosen screw K.
2l Turn hook bushing J lo lhe lefl or righl. as required . lo oblain correcl dislance belween hook
poinl N and need l e .
Caution:
a) If hook bush,ng J. is hard lo lurn . lhen firsl remove rolaling hook G.
b) Never lurn hook bushing J more lhan 1/ 4 lurn in eilher direclion .
Thread gap adjustment:
Check :
1)
Open bed slide plale .
2l Remove lhroal plale .
3)
Turn hand wheel unlil hook poinl is in lhe lhread release posilion as shown in P.
Observation : The hook makes 2 rolalions lo each slroke of needle bar . The lhread
,s
released on lhe
firsl rolalion afler hook has picked up lhread loop from needle.
The gap al poinl
a
should be belween 0 .30 and 0.50 mm. (.012- .020) . The gap al poinl
R
should be
belween 0.30 and 0.40 mm. (.012-.016) and lhe gap al poinl
S
should be belween 0 .64 and 1.15 mm .
( .025-.045) .
4)
Remove bobbin case.
5) Using a wire feeler gauge check gap al poinl T which should be belween 0 .38 and 0.60 mm.
( .015- .023).
Setting:
1) Loosen screws U1 and U2 and visually adjusl poinl V of spring K lo lhe cenler of slol on sup-
porl Y. Thal way lhe gap al poinl S will be CQrreclly sel.
2)
Tighlen screw U2 slighlly.
3) Moving spring X rearwards or forwards . sel adjuslmenl of gap al poinl T .
4)
Adjusl gap al poinl
a
by !urning spring X around screw
U2.
Tighlen bolh screws
U1
and
U2 .
5) Replace bobbin case.
6)
Loosen screw Z and move unil X lo lhe Jell or righl lo adjusl gap al poinl R.
7)
Tighlen screw
Z.
Nole: Adjusl feed dog as described in
IIJ
FOAM
723 (1172)
45