UnionSpecial 398 Classic Series Setup guide

CATALOG
NO.
WH398M
First
Edition
STYLES
398-21
398-22
398-23
398-24
398-25
398-26
398-27
398-28
398-29
Adjusting instructions and
illustrated
parts list
—
ii
U
398
Classic
Series
- Safety
stitch
machines
with
Pushbutton stitch
length
change
I
Finest Quality
Zua
Equipment
From the library of: Superior Sewing Machine & Supply LLC

CATALOG
NO.
WH398M
ADJUSTING INSTRUCTIONS
AND
ILLUSTRATED
PARTS LIST FOR
398
CLASSIC
SERIES
- SAFETY STITCH
MACHINES
WITH
PUSHBUTTON
STITCH
LENGTH
CHANGE
STYLES
398-21 398-24
398-27
398-22
398-25 398-28
398-23
398-26
398-29
First Edition
Copyright
1982
By
Union
Special Corporation
Rights
Reserved in
All Countries
Printed in
U.S.A.
July,
1982
2
From the library of: Superior Sewing Machine & Supply LLC

CLASS
DESCRIPTION
Small
frame,
high
speed,
high
capacity,
differential
feed,
vertical
needle,
Safety
Stitch
machines.
The
needle
drive
mechanism
moves two
straight
needles
in
a
vertical
plane.
Two
independent
rows
of
stitching
are
produced
-
“Double-Lock”
stitch
at
the
left
needle
and
two
or
three
thread
overseaming
stitch
at
the
right
needle.
Machines
include
fabric
trimming
mechanism,
adjustable
looper
avoid
motion,
fully
enclosed
automatic
lubrication.
TECHNICAL
DATA
STITCH
AND
SEAM
TYPE
Specification
516-SSa-2
Spreader
furnished
for
conversion
to
Specification
515—SSa-2
FEED
SYSTEM
Main
and
differential
feed
mechanisms.
Push
button
stitch
length
adjustment
with
independent
thumbscrew
control
for
differential
feed
MAXIMUM
SPEED
5500
R.P.M.
(Depending
on
operation)
LUBRICATION
Enclosed
automatic
splash
system
with
oil
return
pump
NEEDLE
GAUGE
See
machine
styles
(Seam
width)
NEEDLE
GAUGE
EXPLANATION.
Example:
On
Style
398-27
the
12
3/16
is
gauge
of
machine.
The
12
indicates
the
distance
between
needles
graduated
in
1/64
increments,
thus
12
is
12/64
or
3/16 inch
between
needles.
The
fraction
3/16
represents
the
width
of
overedge
seam.
The
total
seam
width
is
the
sum
of
the
two
figures,
i.e.,
3/16
+
3/16
or
total
seam
width
of
3/8
inch.
MACHINE
STYLES
398-21
(8-1/8
Ga.)
For
seaming
light
to
medium
weight
fabrics.
Short,
narrow
presser
foot
with
matiching
feeds
and
throat plate
allow
stitching
on
short
radius
curves.
Typical
application
-
setting
sleeves
and
side
seaming
work
shirts,
robes
and
pajamas.
398-22
(8-3/16
Ga.)
398-23
(12-3/16
Ga.) General
purpose
machine
for
seaming
light
to
heavy
weight
fabric.
Design
of
sewing
parts
allows
machine
to
be
used
on
a
variety
of
gar
ments
ranging
from
shirts
and
blouses
to
women’s
sportwear
and
jackets.
398-24
(8-3/16
Ga.)
Same
as
Style
398-22
except
fitted
with
narrow
tractor
type
presser
foot
and
related
sewing
parts
for
crossing
heavy
seams.
398-25
Same
as
Style
398—24
except
12—3/16
gauge.
398-26
(5-1/8
Ga.)
398-27
(12-3/16
Ga.)
For
seaming
medium
to
heavy
weight
fabrics.
Typical
applica
tion
-
assembling
and
seaming
operations
on
jeans,
work
clothing,
jackets
and
women’s
sportwear.
3
From the library of: Superior Sewing Machine & Supply LLC

MACHINE
STYLES
(Continued)
398-28
Same
as
Style
398-27
except
fitted
with
tractor
type
presser
foot
and
related
sewing
parts
for
crossing
heavy
seams.
398-29
Same
as
Style
398-21
except
12-3/16
gauge.
NOTE:
All
machine
styles
listed
can
be
furnished
with
“AIR-KLIPP’
vacuum
type
chain
cutter.
IDENTIFICATION
OF
MACHINES
Each
UNION
SPECIAL
machine
carries
a
style
number,
which
on
this
class
machine
is
stamped
in
the
style
plate
located
to
the
right
rear
of
machine.
The
serial
number
is
stamped
on
extension
of
casting
at
right
rear
base
of
machi
ne.
LUBRICATION
Oil
capacity
of
Class
398
is
eight
ounces.
Use
a
straight
mineral
oil
with
a
Saybolt
viscosity
of
90
to
125
seconds
at
100
degrees
F.
This
is
equivalent
to
Union
Special
Corporation
Specification
No.
175.
Machine
is
filled
with
oil
at
spring
cap
under
top
cover
or
at
oil
filler
screw
between
tension
disc
support
and
top
cover.
Before
operating,
check
oil
level
at
sight
gauge
on
front
of
machine.
When
proper
oil
level
is
reached,
red
bulb
on
oil
level
indicator
will
register
between
red
gauge
lines.
To
drain
oil
remove
magnetic
plug
on
back
of
machine
near
bottom
edge
of
base.
Clean magnetic
plug
of
any
metallic
material
that
may
have
accumulated
in
crankcase.
Oil must
be
changed
periodically
to
minimize
wear.
THREADING
Be
sure
machine
is
threaded
properly
according to
threading
diagram
Fig.
1,
for
five
thread
machines
or
Fig.
1A,
for
four
thread
machines.
THREADING
DIAGRAMS
Before
threading
machine;
unlock
presser
foot
release
bushing,swing
presser
arm
and
cloth
plate
out of
position;
pull
upper
looper
thread
tube
up
for
five
threads.
Turn
handwheel
in
operating
direction
until
needles
are
at
highest
position.
Thread
tweezers
No.
660-272
and
threading
wire
No.
39899
A
are
furnished
with
machine
to
aid
in
threading.
Thread
machine
in
sequence
as
shown
in
Fig.
1;
(1) lower
overedge
looper
thread,
(2)
401
looper
thread,
(3) upper
overedge
looper
thread,
(4)
rear
needle
thread
and
(5)
front
needle
thread.
Push
upper
looper
thread
tube
down.
Thread machine
in
sequence
as
shown
in
Fig.
1A;
(1) overedge
looper
thread,
(2)
401
looper
thread,
(3)
rear
needle
thread
and
(4)
front
needle
thread.
4
From the library of: Superior Sewing Machine & Supply LLC

Fig.
1
5
TUBE
UP
From the library of: Superior Sewing Machine & Supply LLC

TURN
TO RELEASE
PRESSER
ARM
Fig.
1A
6
From the library of: Superior Sewing Machine & Supply LLC

-
-
ADJUSTING
iNSTRUCTIONS
NOTE:
Instructions
stating
direction
or
location,
such as
right,
left,
front
or
rear
of
machine;
are
given
relat
ive
to
operator’s
position
at
the
machine.
The
handwheel
rotates
clockwise,
in
operating
direction;
when
viewed
from
the
right
end
of
machine.
EXAMINE
NEEDLES
TO
ASSURE PROPER
TYPE
AND
SIZE
ARE
BEING
USED
(EXAMPLE:
120
GS-090/036).
THE
FOLLOWING
CHECKS
RE
LATED
TO
NEEDLES
ARE
IMPORTANT
FOR
SUCCESS
FUL
OPERATION.
IMMEDIATELY REPLACE
AND
DIS
CARD
DEFECTIVE NEEDLES.
-
Roll
the
needle
over
a
flat
surface
to
check
straightness.
If
the
needle
is
bent
it
will
wobble;
as
shown
(A,
Fig.
2).
-
Use
the
thumbnail
test
to
check
for
bluntness
as
shown
(B,
Fig.
2).
-
Check
for
any
sharpness
around
the
eye and
grooves
of
the
bottom
of
the
eye!
Seesaw
the
thread
through
for
a quick
sharp
it
will
cut
the
thread;
as
shown
(C,
Fig.
2).
-
Make
sure
the
needles
are
all
the
way
up
in
needle
holder
with the
spot
or
scarf
to the
rear;
as
shown
(D,
Fig.
2).
Machines
shipped
from
the
factory
are
sewn
off
using
needles
listed:
Machine
Style
Type
and
Size
398-21,
398-22,
398-23, 398-24, 398-25, 398-26,
398-29
120
GS-090/036
398-27,
398-28
120
GAS-125/049
making
adjustments
involving
the
needles,
loopers
or
needle
guards,
use
new
needles
of
correct
type
and
size.
SEE
FOLLOWING
CHART
FOR
DESCRIPTIONS
AND
SIZES
OF
NEEDLES
AVAILABLE
FOR
CLASS
398
MACHINES.
____________
Description
_______________
Round
shank,
round
point,
set
point,
extra
080/032,
short,
double
groove,
struck
groove,
ball
100/040,
eye,
spotted,
rounded
scarf,
with
3/64
125/049,
inch
(1.2mm)
radius
at
scarf,
chromium
plated.
Same
as
Type 120
GS
except
it
has
a
modi-
110/044, 125/049,
fled
point
140-/054.
Fig.
2
and
hooks
on
the
tip
of the
needle;
needle.
Don’t
forget
the
check.
If
the
eye
is
and
positioned
correctly
NOTE:
Before
always
Needle
Type
120
GS
120
GAS
Size
Available
075/029,
090/036,
110/044,
140/054.
7
From the library of: Superior Sewing Machine & Supply LLC

Needle
Type
Description
Sizes
Available
120
GFS
Same
as
Type
120
GS
except
it
has
a
reduced 110/044,
125/049.
eye
and
groove,
120 GHS
Same
as
Type
120
GS
except
it
has
a
thin
ball
075/029, 080/032,
point.
090/036,
100/040,
110/044,
125/049,
140/054.
120 GKS
Same
as Type
120 GHS
except
it
has an
over-
075/029,
080/032,
size ball
eye.
090/036, 100/040,
110/044.
To
have
needle
orders
promptly
and
accura
tely
filled,
an
empty
package,
a
sample
needle,
or
type
and
size
number
should
be
forwarded.Use
description
on
label.
A
complete
order
would
read:
“1000
Needles,
Type
120
GS,Size
090/036”.
NEEDLE
REPLACEMENT
To
replace
needles,
turn
handwheel
in
oper
ating
direction until
needles
reach
highest
position.
Rotate
presser
foot
release
lever
(A,
Fig.
3)
counterclockwise
and
swing
presser
foot
(B)
to
the
left.
Loosen
screws
(C)
and
remove
needles.
Insert
new
needles
against
stop
in
holder
with
scarf
of
needle
positioned
to
the
rear;
tighten
screws
(C).
Swing
presser
foot
(B)
into
position
and
lock
presser
foot
release
lever
(A).
NEEDLE ALIGNMENT
Needle
must
center
in
needle
slots
of
throat
plate
(left
to
right)
as
shown
in
Fig.4.
If
adjustment
is
required,
loosen
screws
(A,
Fig.
5)
and
needle
lever
binder
screw
(A,
Fig.
6).
Align
needles
to
center
in
throat
plate
needle
slots
by
turning
eccentric
needle
head
guide
bar
(B,
Fig.
5).
Position
needle
lever
to
left
or
right
on
its
cross
shaft
to
correspond
with
the
repositioning
of
eccentric
guide
bar.
Manually
move
needle
head
(C)
up
and
down
several
times to
ensure
that
the
needle
lever
aligns
with
the
needle
head.Tight
en
screws
(A).
Temporarily
tighten
screw
(A,
Fig.
6) and
proceed
to
needle
height
ad
justment.
NEEDLES
ARE
CENTERED
LEFT
TO RIGHT
Fig.
4
—C
Fig.
5
8
From the library of: Superior Sewing Machine & Supply LLC

NEEDLE
HEIGHT
Rotate
handwheel
in
operating
direction
until
needles are
at
highest
position.
Speci
fied
height
is
17/32
inch
(13.5mm)
from
point
(tip)
of
needles
to
top
of
throat
plate
as
shown
in
Fig.
7.
If
adjustment
is
required,
loosen
binder
screw
(A,
Fig.
6)
and
position
needle
lever
(B)
up
or
down
as
required
to attain
specifi
ed
dimension.
Tighten
screw
(A,
Fig.
6).
Ro
tate
handwheel
in
operating
direction
and
check
for
binds
in
needle
head
assembly.
Should
a
bind
exist,
refer
to
NEEDLE
ALIGN
MENT.
Needle
height
gauge
No.
21227
DD
can
be
used
by
placing
it
on
top
of
throat plate
and
rotate
handwheel
to
bring
needle
head
down
so
its
bottom
rests
on proper
step of
gauge
AT
BOTTOM OF
DOWNSTROKE.
You
will
note
two
levels
on
gauge;
upper
step
is
for
these
machines
re
quiring
17/32
inch
(13.5mm)
needle
height,
while
the
lower
step
is
used
for
other
machine
styles
requiring
a
7/16
inch
(11.1mm)
setting.
PRIOR
TO
MAKING THE
FOLLOWING
ADJUSTMENTS,
RE
MOVE
CLOTH
PLATE,
FABRIC
GUARD,
CHIP
GUARD,
UPPER
KNIFE,
LOWER
KNIFE,MAIN
AND
DIFFERENTIAL
FEEDS.
CLOTH
PLATE
To
remove
cloth
plate
(A,
Fig.
8) loosen
screw
(B)
and
lift
upward
with
stud
(C)
and
screw
(D)
assembled.
Before
replacing,
tighten
screw
(D)
while
holding
stud
(C)until
all
end
play
is
removed.
Cloth
plate
must
be
allowed
to
swing
open,
so
do
not
over
tighten
screw
(D).
Assemble
cloth
plate
to
machine
by
inserting
stud
(C)
with
flat
and
“V’
notch
to
rear,
into
hole
in
bed
casting.
Tighten
screw
(B)
to
press
“V’
notch
of
stud
(C)
against
screw
(D).
This
locks
screw
CD)
and
stud
(C)
in
position
and
allows
cloth
plate
to
swing
open.
Fig.
6
lTII
I
17/32 inch
••
(13.5mm)
1
Fig.
7
Fig.
8
9
From the library of: Superior Sewing Machine & Supply LLC

LOWER
OVEREDGE
LOOPER
PRIOR
TO
CHECKING
LOOPER
ADJUSTMENT,
REMOVE
FRONT
AND
REAR
NEEDLE GUARDS.
LOOPER
GAUGE
-
With
looper
(A,
Fig.
9)
at ex
treme
left
position,
distance
from
looper
point
to
centerline
of
rear
needle
should
be
3/32
inch
(2.4mm)
as
shown
in
Fig.
9.
PRIOR
TO
ADJUSTING LOOPER,
POSITION
UPPER
LOOPER/SPREADER
UP
AND
AWAY
FROM LOWER
LOOPER.
Rotate
handwheel
to
position
looper
at
ex
treme
right
end
of
travel
and
loosen
clamp
nut
(B,
Fig.
9).
Rotate
handwheel
to
position
looper
at
extreme
left
end
of travel
and
set
looper
gauge
by
adjusting
looper
in
or out of
looper
shaft
(C).
Rotate
handwheel
and po
sition
looper
into
scarf
of
rear
needle
and
set
looper
point
to
touch
but
NOT
deflect
needle.
Tighten
clamp
nut
(B)
securely
and
recheck
looper
gauge.
REAR
OVEREDGE
NEEDLE
GUARD
Remove
spring
from
inside
of
lower
knife
holder
(A,
Fig.
10)
and
assemble
lower
knife
holder
into
throat
plate
support
block.
Re
place
rear
needle
guard
(B)
using
screw
(C)
with
front
edge
of
guard
centered
in
slot
of
knife
holder
(A)
as
shown.
Tighten
screw
(C)
temporarily
to
hold guard
in
position
yet
allows
it to
be moved.
Rotate
handwheel
in
operating
direction
so
the
lower
overedge
looper
(D)
moves
from
the
extreme
left
po
sition
into
the
scarf
of
rear
needle.
Move
guard
(B)
forward
until
the
front
guarding
surface
contacts
the
needle
but
does
NOT
de
flect
it.
Set
guard
as
low
as
possible
so
that
it
will
not
interfere
with
needle
thread
as loop
is formed
to
rear
of
needle.
Tighten
screw
(C)
securely.
Guard
should
not
inter
fere
with
lower
knife
holder
movement
or
con
tact
lower
overedge
looper
at
any
point.
FRONT OVEREDGE
NEEDLE
GUARD
Assemble
front
overedge
needle
guard
(E,
Fig.
10)
to
throat
plate
support
using
screw
(F).
Rotate
handwheel
in operating
direction
to
position
needle
at bottom
of
stroke.
Set
guard
to needle
with
minimum
clearance
-
approximately
.004
inch
(.10mm).
Tighten
screw
(F)
securely.
DO
NOT
PINCH
NEEDLE
BETWEEN
FRONT
AND
REAR
GUARDS.
Fig.
9
Fig.
10
Fig.
11
10
From the library of: Superior Sewing Machine & Supply LLC

OVEREDGE UPPER LOOPER
AND/OR SPREADER
NOTE:
When
using
needle
sizes 075/029
throuqh
100/040
fit
machine
with
upper
looper
No.
39808 A.
Looper
No. 39808
C
is
re
commended for
use
with needle
sizes
110/044
through
140/054.
PROPER ADJUSTMENTS
TO
THE
UPPER
LOOPER
OR
SPREADER
ARE
ESSENTIAL
FOR
SUCCESSFUL
OPERA
ATION.
THE PATH
TRAVELED
BY
THE
UPPER
LOOPER
OR
SPREADER
EFFECTS
THE
MAXIMUM
SEAM THICKNESS
SEWN.
Rotate
handwheel
in
operating
direction
and
closely
observe
the path of
the
up
per
looper/spreader
as
it
moves
from
extreme
right
position
and
approaches
lower
looper
(Fig.
11).
Point of
looper
or
thread
pick
up on
spreader
must pass
the
notch
in head
of
lower looper
with
mininum
clearance.
Upper looper
should
pass under
the
lower looper
thread
and
spreader
must
pick
up
lower
looper
thread
with
lower point.
Continue
rotating
handwheel
until
upper
looper/spreader
reaches the
extreme
left position
at
the
needle
(Fig.
12).
At
this
point
the
upper looper
should
be
in
position
so
the
descending
rear needle
will
pass to
the right
of the
upper
looper
thread
which
extends
from
the eye
of
the
looper
to
the
previouslyformed
stitch.
On
machines
using
a
spreader,
the
spreader
should
now
be
in
position
so
the
descending
needle
will
pass
to
the
right
of
the
lower looper
thread
extending
from
the
notch
of
the
spreader
to
the
previously
formed
stitch.
THE
UPPER LOOPER/SPREADER
SHOULD
NOT
RUB
AGAINST
THE
LOWER
LOOPER
OR
NEEDLE
AT
ANY
POINT
OF
TRAVEL.
LOOPER
(SPREADER)
AT
EXTREME
RIGHT END
OF
TRAVEL
Fig.
15
Figures
13,
14,
15
and
the
chart following
relate
approximate
dimensions
for
adjusting
upper
looper/spreader
at
their
extreme
right
and
left
positions
of
travel
SHANK
EXTENDED DEGREE
BACK
HEIGHT
ABOVE
POINT TO
LEFT
OF
REAR
ABOVE
HOLDER
OF
VERTICAL
THROAT
PLATE
NEEDLE
CENTERLINE
‘‘B’’
‘‘E’’
‘‘F’’
‘‘F’’
Fig.
13
Fig. 13
Fig.
14
Fig.
15
Fig.
14 Fig.
15
W/LOOPER
1/32”
45
21/32”
5/32”
(.8mm)
(1.6.7mm)
(4mm)
W/SPREADER
1/32”
15
21/32”
5/32”
(.8mm)
(16.7mm)
(4mm)
Fig.
12
LOOPER
AT
EXTREME
LEFT
END
OF
TRAVEL
-F
SPREADER
AT
EXTREME
LEFT
END
OF
TRAVEL
Fig.
13
Fig.
14
11
From the library of: Superior Sewing Machine & Supply LLC

To
adjust upper
looper/spreader,
follow
instructions
in sequence
as follows:
1.
Position
upper
looper/spreader
at
the
right end
of
travel,
loosen clamp
screw
(A,
Fig.
13)
and set looper/spreader
shank to
diniension
‘B’
above holder.
Tighten
screw
(A) lightly.
2. With
upper
looper/spreader
still
positioned
at
the right end of
travel,
loosen
screw
(C)
and
rotate
holder to
align shank
of looper/spreader
to
the
specified
line in
castin9 denoting
15,
30 or
45
decirees back
of
vertical
(location
“D”).
Tighten screw
(C)
liqhtly.
3. Rotate
handwheel
in operating
direction
bringing
the upper
looper/spreader into
the
LOWER
looper. The POINT
of upper
looper or THREAD
PICK-UP of upper
spreader
should be
set to enter
the notched area
behind
the
head
of the lower
looper -
See Fig.
11.
4.
Continue
to rotate
handwheel in
operating
direction
until upp’ér
looper/spreader
is
at
extreme
LEFT end
of travel.
Rotate upper
looper/spreader
holder
as re
quired
to position
POINT
of
upper looper
to dimension
“E”,
Fig.
14
or
LOWER
POINT of
upper
spreader
to dimension
“E”,
Fig.
15
from
top of throat
plate.
5.
With
upper
looper/spreader
still
positioned at
left
end
of
travel,
it may be
necessary
to
move looper/spreader
holder
in
or
out
of
its shaft to set
POINT of
looper
dimension
“F”,
Fig.
14
or
LOWER
POINT of spreader
dimension “F”,
Fig. 15
which
is
to
the left
of
centerline
of rear
needle. Rotate
handwheel to
position
upper
looper/spreader
to the
right end of
travel before
tightening screw
(C,
Fig.
13) securely.
Tighten
screw
(A).
6.
If the
needle(s)
are
beina
deflected
by the upper
looper/spreader,
clearance to
the
needle
can
be
increased
by
reducing the
length
of looper/spreader
shank
above
holder
(dimension
“B”), See
Step 1.
It will
then be
necessary
to slightly
reduce
the
angle of
the
shank
back of vertical,
See
Step
2.
Set
looper/spreader
to
lower
looper, See
Step 3.
Reversing this procedure
will position
the looper!
spreader
closer
to
the needle.
401
STITCH
LOOPER
ADJUSTMENTS
PRIOR
TO
CHECKING LOOPER
REMOVE
FRONT
NEEDLE
GUARD
AND REAR NEEDLE
GUARD OUT
OF
POSITION.
Loosen
screw
(A, Fig. 16)
and
push
looper
down so
that its
shank rests
on
shaft.
Rock
looper blade
to
front and rear
while
tightening
clamp
screw
(A).
This will
ensure
the
clamp screw is
securing
looper on flat
surface
of looper
shank.
With looper
to
extreme right, loosen
binder
screw
(B,
Fig.
16). Position
looper
Fig.
16
holder right
or left
so the
point
of looper
is
3/32 inch
(2.4mm) from
centerline
of
front
needle
as shown in Fig.
16. Turn
handwheel in
operating
direction
until
point
of looper
enters
scarf
on
back
side
of needle.
Move
looper blade
forward until
it
touches
but
does
NOT
deflect needle.
Tighten binder
screw (B).
12
—
From the library of: Superior Sewing Machine & Supply LLC

To
form
stitch
type
401,
the looper
mov
ing
to
the
left
passes to
rear
of
needle
and
enters
the
thread
loop
formed
as
needle
rises
(A,
Fig.
17).
Traveling
to
the
right,
looper
passes
to
front
of
descending
needle
which
enters
a
triangle
formed
by the looper
thread,
blade
of
looper
and
needle
loop
around
looper
blade
(B).
This
front
to
rear
movement
of
looper
is
termed
“AVOID
MOTION”.
Avoid
motion
of
the
looper
occurs
in
unison
with
its right
and
left
travel.
As
a
result,
the looper
point
travels
in
an
elliptical
path
as
shown
in
Fig.
17.
Minimum
clearance
between
needle
and
looper
at
functions
shown
in
Fig.
17
must
be
maintained.
The
descending
needle
(B)
may
contact
the
looper
blade
lightly.
Too
much
clearance
or
needle
deflection
at
A
or
B
can
cause
skipped
stitches,
broken
needles,
etc..
The
looper
avoid
motion
on
these machines
can
be
adjusted
to
obtain
proper
conditions
for
various
size
needles
used.
ECCENTRIC
SETTING
NEEDLE
RANGE
BY
SIZE
S
-
SMALL
M
-
MEDIUM
L
-
LARGE
075/029,
080/032,
090/036
080/032,
090/036,
100/040
110/044,
125/049,
140/054
Loosen
nut
(A,
Fig. 18).
Rotate
handwheel
until
needles
are
at
lowest
position.
Align
proper
mark 5,
M
or
L
on
stud
(B)
to
timing
mark
on
link
(C).
Torque
nut
(A)
to
25
in.
lbs.
(29
cm/kg).
Re-check
401
looper
setting,
then replace
bottom
cover
and
torque
cover
mounting
screws
to
19—21
in. lbs.
(22—24
cm/kg).
Fill
machine
with
oil
to
proper
level.
NOTE:
If
needed,
stud
(B) can
be
positioned
to
timing
mark
at
any
point
between
5,
M
or
L
to
obtain
proper
amount
of
looper
avoid.
Check
clearance
between
401
looper
and
needle
following
any
adjustment
to
the looper
avoid
setting.
LOOPER
AVOID
ADJUSTMENT
C
NEEDLE
DIRECTION
OF FEED
PATH
LOOPER
POINT
TRAVFLS
AROUND
NEEDLE
Fig.
17
Fig.
18
Should
conditions
described
previously
indi
cate
adjustments
are
required;
drain
the
oil
and
remove
bottom
cover
from
machine.The
“S”,
“M”
or
“L”
marked
on
eccentric
stud
are aligned
to
the
timing
mark on
looper
a
void
link
according
to
the
range
of
needle
size
used.
SEE
CHART:
13
From the library of: Superior Sewing Machine & Supply LLC

—
—
______________
401
STITCH
REAR
NEEDLE
GUARD
Rear
needle
guard
(A,
Fig.
19)
should
prevent
the
looper
point
from
striking
the needle
as
the
looper
moves
from
the
right
and
enters
the
scarf
of
front
needle.
Rotate
handwheel
in
operating
direction
so
that
the
point
of
looper
moving
from
ex
treme
right
position
enters
the
scarf
of
front
needle.
Loosen
screw
(B)
and
move
guard
for
ward to
touch
but
NOT
deflect
needle.
Turn
handwheel so
needle
is
at
lowest
position.
Raise
or
lower
guard
so
top
of
needle
eye
is
slightly
above
guarding
surface
of
rear
needle
guard
-
REAR
GUARD
MUST
NOT
INTERFERE
WITH
FORMATION
OF
THREAD
LOOP
FORMED
AS
NEEDLE
RISES.
Re-check
guard
to needle
position
de
scribed
earlier
and
tighten
screw
(B).
401
STITCH
FRONT NEEDLE
GUARD
With
needles
at
lowest
position,
front
needle
guard
(C,
Fig. 19)
is
set with
minimum
clear
ance
to
needle,
.004
inch (.10mm).
DO
NOT
PINCH
NEEDLE
BETWEEN
FRONT
AND
REAR
NEEDLE
GUARDS.
401
LOOPER
MUST
NOT
RUB
GUARD.
If
adjustment
is required,
loosen
screw
(D)
and
locknut
(E).
With
needle
at
lowest
position
set
guard
(C)
so
it’s
relatively
close
to
the needle
but
NOT
touching
it.
Tighten
screw
CD).
Turn
screw
(F)
in
against
guard.
Continue
turning
screw
(F)
to
force
guard
slightly
to
the
rear
maintaining
.004
inch
(.10mm)
clearance
to
needle.
Tighten
locknut
(E).
MAIN
AND
DIFFERENTIAL
FEEDS
ASSEMBLE
MAIN,
DIFFERENTIAL
FEEDS
AND
THROAT
PLATE
TO
MACHINE.
Rotate
handwheel
in
operating
direction
and
stop
when
teeth
of
rising
feeds
first
appear
above
top
surface
of
throat
plate.
The
feeds
should
be level
with
the
throat
plate
at this
time.
With
feeds
at
highest point
of
travel,
teeth
should
extend
approximately
3/64
inch
(1.2mm)
above
throat plate
as
shown
in
Fig.
20.
To
level
feeds,
loosen
lock
screw
(A,
Fig.
20)
and
rotate
tilt
adjusting
pin
(B)
to position
rear
of
feeds
up
or
down.
Tighten lock
screw
(A)
securely.
Feed
height
is set
by
loosening
attaching
screws
and moving
feeds
to
height
re
quired.
Retighten
screws.
Fig.
19
Fig.
21
14
From the library of: Superior Sewing Machine & Supply LLC

LOWER
KNIFE
INSERT
SPRING
BACK
INTO LOWER
KNIFE
HOLDER
AND
ASSEMBLE
HOLDER
TO THROAT
PLATE
SUPPORT.
Upper
edge
of
knife
(A, Fig.
21) is
set
even
with
top
surface
of
throat
plate.
Positioning
of the
lower
knife
cutting
edge
left to
right
to
obtain
proper
seam width
is
determined
by
the
width
of the
stitch
tongue
of
the
throat
plate.
If
adjustment
is
required,
loosen
screw
(B)
and
move
knife
up
or
down
so
its
cutting
edge
is
even
with
top of
throat
plate.
Tight-
Fig.
22
en
screw
(B).
If
cutting
edge
of
knife
is
tilted,
loosen
screw
(C) and
rotate
holder
(D)
front
to
rear
as
required.
Tighten
screw (C).
Holder
should
move
freely
left
to
right
and
not bind with
overedge
rear
needle
guard
centered
in
slot
of
knife
holder
shaft.
NOTE:
See
shear
angle
adjustment.
UPPER
KNIFE
REMOVE
NEEDLES
AND
RE-ASSEMBLE
UPPER
KNIFE
HOLDER
INTO
ITS
SLOT
ON
UPPER
KNIFE
DRIV
ING
ARM.
ALSO
REPLACE
UPPER
KNIFE
IN
ITS
HOLDER
AND
HOLD FIRMLY
IN
POSITION.
At
lowest
position
the
front
tip of
cutting
edge
of
upper
knife
should
extend
1/32
inch
(.8mm)
below
cutting
edge
of
lower
knife.
With
upper
knife
CE,
Fig.
21) at
lowest
point
of
travel;
position
front
tip
of
its
cutting
edge
1/32
inch
(.8mm)
below
cutting
edge
of
lower
knife
by
moving
knife
holder
(F)
left
to
right.
Upper
knife
must
be
held firmly
against
lower
knife
dur
ing
this
adjustment.
Tighten
upper
knife
holder
screw
(G) to
lock
upper
knife
in
position.
Assemble
knife
clamp
(H) and
chip
guard
(J) in
position
using
nut
(K).
Set
chip
guard
(J)
against
top
surface
of
upper
knife
and
slightly
back
of
its
cut
ting
edge.
Tighten
nut
(K).
Loosen
screw
CL) to
enable
spring
pressed
lower
knife
to
move
freely
left
to
right.
If desired,
lower
knife
can
be
locked in
position
by
tightening
screw
CL)
against
knife holder
shaft.
NOTE:
Locking
nut
(M)
must
be
tightened
to
hold
screw
CL) in
position;
screw
(L)
also
serves
as
a
latch
pin for
cloth
plate.
Proceed
to
shear
angle
adjust
ment.
SHEAR
ANGLE
ADJUSTMENT
NOTE:
Be
sure
lower
and
upper
knives
are
adjusted
properly
before
setting
shear
angle.
The
proper
shear
angle
between
cutting
edge
of
upper
and lower
knives
is
1
degree
as
shown
in
Fig.
22.
This
results
in
a
cutting
action
similar
to
that
of
a
pair
of
scissors.
Best
results
are
obtained
if
both
knives
are
sharpened
correctly prior
to
adjusting.
If
adjustment
is
required,
loosen
locknut
(A, Fig.
22)
and lock
lower
knife
holder
out
of
position
away
from
upper
knife
with
screw
(B).
15
From the library of: Superior Sewing Machine & Supply LLC

SHEAR
ANGLE
ADJUSTMENT
(Continued)
Loosen
screw
(C)
and
clamp
screw
(D).
Ad
just
guide
plate
(E)
inward
to
angle
top
front
edge
of
lower
knife
slightly
to
the
right.Hold
guide
plate
(E)
in
position
and
tighten
screw
(C)
and
clamping
screw
(D).
Loosen
screw
(B)
to
allow
lower
knife
holder
to
float
left
to
right.
Tighten
locknut
(A).
PRESSER
FOOT
ALIGNMENT
To
align
presser
foot
bottom,
loosen
clamp
screw
(A,
Fig.
23)
and
unlock
presser
foot
release
lever
(B),
but
do
not
raise
plunger
(C)
from
presser arm
(D).
Adjust
presser
foot
front
to rear
so
front
of
its
needle
slots
align
with
needle
slots
in
throat
plate.
To adjust
presser
foot
so
it
will
lie
flat
on throat
plate;
lift
presser
foot
and
tilt
its
right
edge
up
or
down
as required.
Tighten
clamp
screw
(A),
lock
presser
foot
re
lease
lever
and
check
alignment.
To
align
presser
foot
needle
slots
to
throat plate
needle
slots
left
to
right,
loosen
collar
screws
(A,
Fig.
24)
and
clamp
screw (B).
Adjust
lifter
lever
shaft
(C)
left
or
right
as
required
and
tighten
collar
screws
(A).
Hold
lifter
lever
CD)
up
and
tighten
clamp
screw
(B).
Corpletely
unlock
presser
foot
release
lever
(B,
Fig.
23).
Plunger (C)
should
clear
presser
arm
(D)
without
binding.
On
machines
equipped
with
a
tractor
type
presser
foot;
the
front
edge
of
its
401
stitch
needle
slot
must
be
1/16
inch
(1.6mm)
forward
of
front
edge
of
the
401
stitch
needle
slot
in
throat
plate.
Lift
tractor
presser
foot
to
its
hightest
position
and
tilt
front
of
presser foot
toe
downward. The
rear
of
presser
foot
front
section
must
not
contact
needle.
PRESSER
FOOT
LIFT
Lift
presser
foot
to
highest
position and
rotate
handwheel
in
operating
direction.
Upper
looper/spreader
must
move
from
extreme
right
to
extreme
left
without
contact
ing
presser
foot.
If
adjustment
is
required,
loosen
locknut (E,
Fig.
24)
and
adjust
stop
screw
(F)
so
presser
foot will
not
interfere
with
upper
looper/spreader,
then
tighten
locknut
(E).
Loosen
locknut
(G)
and
set
stop
screw
(H) on
upper
end
of
lifter
lever
arm
so
there is approximately
1/16
inch
(1.6mm) free
motion
in
lifter
lever
before
presser
foot
starts to rise,
then
tighten
locknut
(G).
Fig.
23
Fig.
24
16
From the library of: Superior Sewing Machine & Supply LLC

PRESSER
FOOT
PRESSURE
D
Sufficient
pressure
should
be
maintained
to
E
feed
work
uniformly.
Excessive
spring
press
ure
will
cause
feeds
and
presser
foot
to
wear
prematurely
when chaining.
\
Rotate
handwheel
in
operating
direction
( 1 m)
until
both
main
and
differential
feeds
are
positioned
below
throat
plate.
Loosen
locknut
(A,
Fig.
25)
and
turn pressure
reciulator
(B)
clockwise
for
more pressure
of
counterclock
wise
for
less pressure,
then
tighten
locknut
(A).
NOTE:
Adjusting
pressure
regulator
(B) will
effect
the
function
of
pressure
re
lease
lever
(C).
Plunger
(C, Fig.
23)
should
clear
presser
arm
when
pressure
release
lever
(C,
Fig.
25)
is
unlocked
in
position.
When
release
lever
(C)
is
locked
in
position,
presser
foot
should
be
held
firmly
against
throat
plate.
If
these
conditions
do
not
exist
the
following
adjustment
must
be
made.
Lock
presser
foot
in
position
with
pressure
release
lever
(C);
loosen
capnut
CD)
and
ad
just
nut
(E)
up or
down
so
its
under
surface
is
1/16
inch
(1.6mm)
above
pressure
regulator
(B)
as
shown
in
Fig.
25.
Hold
nut
(E)
in
position
and
tighten
capnut
CD).
SETTING
STITCH
LENGTH
The
actual
stitch
length
produced
is
usually
measured
as
the
number
of
stitches
sewn
per
inch
of
seam.
This
is
determined
by
the
distance
feeds
travel
with
their
teeth
protruding
above
the throat
plate.
Class
398
machines
are
fitted
with
a
feed
system
having
two separate
feed
dogs
-
MAIN
(rear)
and
DIFFERENTIAL
(front).
The
resulting
stitch
length
is
determined
to
a
great
extent
by
travel
of the
main
feed.
Differential
feed
travel
can
be
adjusted
independently
of
the
main
feed and
is
used
to
gather
or
stretch
the fabric
prior
to
being
stitched.
To
adjust
stitch
length,
depress
and
hold
plunger
(A,
Fig.
26)
down,
then
turn
handwheel
in
operating
direction
until
plunger
drops
into
notch
of
stitch
regulator
eccentric.
While
holding
plunger
down,
continually
forcing
handwheel
to
turn
in
oper
ating
direction
will
increase
stitch
length
or
continually
forcing
handwheel
to
turn
in
the
reverse
direction
will
decrease
stitch
length.
Numbers
stamped
in
handwheel
are
for
reference
use only.
If
desired,
plunger
may be
locked
to
prevent
accidental
changing
of stitch
length
by
loosening
locknut (B)
and
by
turning
locking
screw
(C)
inward
to
rest
firm
ly
against
plunger.
Tighten
locknut
(B).
Fig.
25
Fig.
26
17
From the library of: Superior Sewing Machine & Supply LLC

_
DIFFERENTIAL
FEED
TRAVEL
When
differential feed
indicator
pointer CD,
Fig.
26) is
set to “0”
on
the
grad
uated scale
of
indicator plate
(E)
the main and differential
feeds
will
have
the same
travel.
Turning thumbscrew
(F)
clockwise
will
position
the pointer
to the
“+“
portion
of the scale
indicatinq differential
feed travel
is greater than main
feed travel.
Fabric
is
gathered
at this
setting.
Turning
thumbscrew
(F)
counterclockwise
will po
sition
the pointer
to the
“-“ portion
of the
scale indicating
differential feed
travel is less
than main
feed
travel. The
fabric is stretched
at this
setting.
Thumb
screw
adjustments
to
the
differential feed
can
be made while
machine is in operat
ion.
Stop
screw (G)
is
used
to
limit
differential feed
travel
and
prevent
the
diff
erential feed
from striking
the
forward
edge
of
throat plate
slot.
401 STITCH
NEEDLE THREAD
CONTROL
Set adjustable
thread guide
(A, Fig. 27)
near its highest
position until
approximately
1/8
inch
(3.2mm) adjustment
remains
in
slot
as shown
in Fig. 27.
As the eyelet
is
lower
ed more
needle thread
remains in the
stitch.
Having
additional
needle thread in
the stitch
may
be
desirable
when sewing
thick
material.
With needles
at lowest position
loosen
clamp
screw
and
position strike
off
tip
of
thread
pull-off
(B)
1/16
inch (1.6mm) to
1/8
inch
(3.2mm) below
eyelet
(C) as
shown in
Fig.
27.
Fig.
27
With
needles at
highest position
set
eyelet
(C) so
lower
cam surface of
thread
pull-off
(B)
just
contacts the thread
at Ref.
point
(D).
401
STITCH LOWER
LOOPER
THREAD
CONTROL
Thread
take-up cam (A,
Fig. 28) should
be centered
in the
slot
of cast-off support
plate
(B). Loosen
the three mounting
screws
(C)
and position support
plate
(B)
so
cam
does
not rub
it while
rotating handwheel
several
revolutions,
then tighten screws
(C).
To check
thread
take-up action of
cam
(A)
rotate
handwheel
in operating
direction
so that
needles are
at highest
position. The
Fig.
28
leading
flat edge of cam
should now appear
just
above
the cast-off
support plate and
be
gin to
take up the
slack thread.
Loosen
clamp nut (0) and
position
cam,
then
torque
nut
CD)
to 24-25
in/lbs.
(28-29
cm/kg.).
Adjustable
thread
eyelets
CE),
effect
the amount
of looper thread
used in the
stitch.
When set
at
lowest
position,
the
maximum
amount of looper
thread is drawn.
Set
eyelets
initially
down
1/8 inch
(3.2mm)
from
highest position.
NEEDLL UP
18
From the library of: Superior Sewing Machine & Supply LLC

OVEREDGE
NEEDLE
THREAD
CONTROL
With
needles
at
lowest
position,
loosen
screw
securing
needle
thread
cam
pull-off
(A,
Fig.
29)
and
set
the
lower
extended
sur
face
of
its
strike-off
tip
1/32
inch
(.8mm)
below
the
centerline
of
overedge
needle
thread
eyelet
holes
(B)
on
FIVE
thread
mach
ines
or
1/8
to
3/16
inch
(3.2
to
4.8mm)
on
FOUR
thread
machines
-
Ref.
point
(C).
With
needles
at
highest
position,
set
eyelet
(B)
so
the
lower
cam
surface
of
pull-
off
(A)
barely
contacts
thread
at
Ref.
point
(D).
OVEREDGE
LOWER
LOOPER
THREAD
CONTROL
With
needles
at
highest
position,
loosen
screw
(A,
Fig.
30) and
center
lower
slots
of
the
looper
thread
take-up
(B)
front
to
back
to
thread
tube
(C),
then
tighten
screw
(A).
Threading
wire
No.
39899
A should
pass
freely
through
thread
tube
(C)
and
the
lower
slots
of
looper
thread
take-up
-
Ref.
point
(D).
To
set
the
lower
looper
cast-off
blade
(E),
loosen
screw
(F) and
position
blade
up
or
down
until
its
curved
section
-
Ref.
point
(G)
contacts
the
lower
looper
thread
as
soon
as
the
needles
start
descending.
Position
blade
front
to
back,
so
when
the
needles
reach
their
lowest
position
the
lower
looper
thread.barely
contacts
the
vertical
surface
-
Ref.
point
(H)
on
the
cast-off
blade,
then
tighten
screw
(F).
Fig.
29
NEEDLES
IN
HIGHEST
POSITION
OVEREDGE
UPPER
LOOPER
THREAD
CONTROL
With
needles
in
highest
position,
loosen
screw
(J,
Fig.
30)
and
set
upper
looper take-up
eyelet
(K)
in
a
horizontal
position
with
its
mounting
slot
centered
(front
to
back);
also
set
auxiliary
thread
guide
(L)
slightly
above
a
horizontal
position.
At
this
time,
the
upper
looper
thread
should
be
taut
through
the
eyelet
holes
and
should
barely
contact
the
rear
portion
of
the
slot
in
left
side
of
looper
thread
take-up
(B).
Reposition
eyelet
(K)
if
necessary,
(slightly
upward
or
downward)
to
center
thread
in
the
slot
of
take-up
(B),
then
tighten
screw
(J).
9
-D
NEEOLES
UP
L
Fig.
30
19
From the library of: Superior Sewing Machine & Supply LLC

POSITIONING
THE
PURL
If
the
needle
thread
loop
is
NOT
being
set
properly,
excessive
seam
grinning
would
result
as
shown
in
Fig.
31.
Thread
control
adjustments
which
should
be
checked
to
correct
this
condition include:
-
Lower
looper
thread
tension
too
tight.
-
Needle
thread
strike-off
tip
too
low.
-
Lower
looper
cast-off
blade
too
far
towards
the
rear.
-
Needle
thread
tension
too
loose.
If
the
purl
is NOT
being
formed
on
the
edge
of
the
fabric,
an
imbalance
between
the
looper
threads
is
indicated
and
improper
cov
erage
of
the
seamed
edge
would
occur
as
shown
in
Fig.
32.
If the
purl
is
being
pulled
under
the
edge,
check
the
following
thread control
adjustments:
-
Lower
looper
thread
too
tight.
-
Lower
looper
cast-off
blade
too
far
towards
the
rear.
-
Upper
looper
thread
eyelet
too
far
towards
the
front.
-
Upper
looper
thread
tension
too
loose.
If
the purl
is
being
PULLED
over
the
edge
as
shown
in
Fig.
33,
check
the
following
thread
control
adjustments:
-
Upper
looper
thread
tension
too
tight.
-
Upper
looper
thread
eyelet
too
far
to the
rear.
-
Lower
looper
cast-off
blade
too
far
forward.
-
Lower
looper
thread
tension
too
loose.
Fig.
33
THREAD
TENSIONS
Thread
tension
is adjusted
and
regulated
at
the
tension
assemblies.
Tension
on
the
threads
should
be
only
enough
to
secure
proper
stitch
formation.
Using
a
postal
scale,
the
measurements
are
taken
with the
needles
at
the
top
of their
stroke.
The
following
tensions
are
starting
points
only
and
may
have
to
be
changed
due
to
type and
size
of thread
or
material
being
sewn.
BOTTOM
VIEW
Fig.
31
BOTTOM
VIEW
Fig.
32
*
TOP
VIEW
20
From the library of: Superior Sewing Machine & Supply LLC