JUKI MB-372 User manual

I.L^.

MODEL

MB-372

HIGH

SPEED

SINGLE

THREAD

CHAINSTITCH

BUTTON-SEWING

MACHINE

Instruction

Book

TOKYO

JUKI

INDUSTRIAL

CO..LTD.

From the library of: Superior Sewing Machine & Supply LLC

CONTENTS

Page

GENERAL

DESCRIPTION

SPECIFICATIONS

NAMES

PARTS

CAUTIONS

BEFORE

OPERATION

LUBRICATION

MOTOR

PULLEY

AND

BELT

NEEDLES

INSERTING

THE

NEEDLE

THREADING

THE

MACHINE

10.

THE

THREAD

TENSION

11.

FUNCTIONS

THE

THREAD

PULL-OFF

LEVER

12.

THE

THREAD

NIPPER

13.

ADJUSTING

THE

NEEDLE BAR 10

14.

PRODUCE

OPTIMAL

STITCHING

CONDITION

15.

POSITION

THE

NEEDLE

GUARD

16.

TIMING

THE

NIPPER

RELEASING

PLUNGER

TENSION

DISC

NO.

2 14

17.

CHANGING

THE

POSITION

THE

BUTTON

TRAY

•••

18.

STITCH

SELECTING

-15

19.

HEIGHT

BUTTON

CLAMP

20.

ADJUSTING

THE

BUTTON CLAMP PRESSURE

21.

ADJUSTING

THE

BUTTON CLAMP STOP LEVER 18

22. ADJUSTING

FOR

2-HOLES AND 4-HOLES 18

23.

CHANGING

THE

BUTTON

HOLDING

CLAMP

AND

ADJUSTING ITS HEIGHT

24.

CAUSES

MALFUNCTIONS

AND

REPAIRING

25.

ATTACHMENTS

MB-372

BUTTON

ATTACHING

MACHINE

( i ) How to install the snap fastener attachment 22

(ii)

How to install the wrapped-around button clamp attachment 23

(iii)

How to insall

the

shank

button clamp attachment 25

{iv)

How to

install

the

metal

shank

button clamp attachment

•••

From the library of: Superior Sewing Machine & Supply LLC

GENERAL

DESCRIPTION

JUKI

Model

MB-372

is a single thread, chain stitch, button sewing

machine.

is widely used to

attach

flat two hole or four hole

buttons

as well as snap fasteners, shank

buttons

and

metal shank buttons.

This

is an ideal machine to attach these buttons on all knit

goods,

men's

shirts, work uniforms, ladies' suits

and

men's suits.

This machine is equipped with 8 stitches, 16 stitches

and

32 stitches

and

these

stitches are interchangeable without changing the stop motion

From the library of: Superior Sewing Machine & Supply LLC

cams. A speed slowing device, an exclusive

JUKI

attachment, is

incorporated into this machine

and

consequently loosening of screws or

malalignment of stitches which sometimes characterize amachine with

a stop motion mechanism is completely eliminated and assures a safe

and

stable stitching condition.

SPECIFICATIONS

Model

Sewing type

Sewing fabric

Sewing speed

Button-sewiniar

Needle

bar

stroke

Needle

Stitch

number

Feed

length

Button

size

Presser

bar

life

Button

clamp

lift

Thread

nipper

Stop motion

Lubrication

Power

required

Lubricating

oil

2.hole

button

4-hola

button

MB-372

Single

thread chainstitch button-sewing

Knit goods, shirts & working wear etc.

Max.

1500s.p.m.

1 Lengthwise feed 0 2-hole button

2Lengthwise/crosswise feed

•••

4-hole

button

3 By attachment Snap, Shank, Metal

shank or

Wrapped

round

48.6

m/m

(1-7/8")

TQx7

(175x7) or

TQxl)

(175x1) #14-#18

16,

32,

Gam:

not to be changed

6, 12, 24,

Cam:

to be

changed

Crosswise feed •••2.5~6.5

m/m

(3/32~l/4")

Lengthwise

feed

••-0^2.5^6.5m/m (0~3/32~l/4")

Dim:

10-27

m/m

(3/8-1-1/32")

Std.

m/m

(15/32")

Automatic or foot operated

2-way

cam

type

Automatic (with speed-slowing device) type

Hand

oil

type

200

New

Defrix

Oil

No.

1 &

New

Defrix

grease

Snap

Shank

button

Metal

sbankbutton

Wrapped

round

button

From the library of: Superior Sewing Machine & Supply LLC

NAMES

PARTS

Needle

bar

(§)

Nipper

block

(|i)

Needle

bar

lever

® Thread

pull-oft^

lever

L shaped thread guide ® Tension disc No. 2 0 Tension

disc

No.

Nipper

bar 0 Thread

guide

No.

1 @

Nipper

bar

actuating lever @ Machine arm @ Button clamp lifting link

Needle

bar lever connecting rod

(Q)

Lengthwise

feed

graduated plate

(!|)

Stop

motion

disc

spring

(g)

Rubber washer ® Stop motion

disc

applying pressure lever @

Needle

driving pulley @ Stop motion disc

Ball

joint eccentric @ Loopershaft tube

(§)

Crosswise

feed

graduated

plate @ Loop

positioning

finger

cam,

rear @

Loop

positioning

finger

cam, front @ Looper @ Button clamp leverjaw @ Feed plate

Needle

plate

Needle

Button

clamp

lifting

rod

(0)

shaped

button

clamp

lifting

rod @

Tension

disc

No.

3 @ Thread

guide

No.

Needle

bar

bearing

block

& thread

guide

Nipper

releasing

plunger

knurled

thumb

nut

(g)

Button

clamp

pressure

adjusting

spring

nut

— 3 —

From the library of: Superior Sewing Machine & Supply LLC

CAUTIONS

BEFORE

OPERATION

* After unpacking the crating, clean out all the dirt of packing

and

oil all the oiling holes.

* Before operating, be sure to

read

the Instruction Book thoroughly

and

digest its

contents.

The

machine is thoroughly adjusted at the time of shipping but

to be absolutely sure, release

the

stop

motion

mechanism

and

rotate

the

machine with your

hand

before

turning

the switch on.

The

maximum

sewing speed

this

machine

is 1,500s.p.m.

but

for

the first month operate the machine at the speed of

1,200-1,300

s.p.m.

For

the

number

revolutions, please refer to the

Chapter

"Motor

pulley

and

Belt".

The

rotational direction of

the

machine is shown by the

arrow

oia

'ireotiM

5. LUBRICATION

(Refer

to Fig. 1, 2, 3,

and

In order to ensure a long life of the machine

and

to run it in a

smooth-running condition, the machine should be oiled twice daily,

before the morning

and

afternoon starts. Oil*all holes shown by the

arrows with

JUKI

New Defrix Oil No. I or

JIS

Special No. 1 White

— 4 —

From the library of: Superior Sewing Machine & Supply LLC

Spindle Oil. Remove the right side arm cover, remove the screw d),

Fig. 2, of the needle driving pulley, check the grease level and replenish

it, if required.

Also, loosen the machine

arm

and

bed set screw ®, Fig. 1,

and

il"

the

machine is tilted as shown in Fig. 4, you can sec the driving

gear

(T)

and

the looper shaft driven

gear

(2).

Grease these gears too. Some

times check

and

see if the oil comes up to the surface of the felt inside

the machine sub-base and if not, fill up with oil.

MOTOR

PULLEY

AND

BELT

For connecting directly to the power source, use an electric

motor of 3-phase 1/4

HP.

The

relation between the

number

rotation

of the

machine

with

the

effective

diameter

of the

motor

pulley

shown

in the

table

below.

(Effective

diameter

the

motor

pulley

means

the

diameter

measured

from

the

center

the

belt

when

wound

around).

— 5 —

From the library of: Superior Sewing Machine & Supply LLC

Cycles

Rotation

Part

No.

motor

pulley

Effective

diamater

motor

pulley

1,500

r.p.m.

1,200r.p.m.

B710137200H

B710237200H

m/m

3/4")

58.2

m/m

1/4")

1,500r.p.m.

1,300

r.p.m.

B710237200H

B710337200H

58.2

m/m

(21/4")

50.3

m/m

15/is")

NEEDLES

At the time of shipping, the needle No.

TQx7

(175x7) is attached

to the machine

but

needle No.

TQx

1(175x1) can also be used.

TQx

needle is shorther

than

TQx7,

so when attaching buttons, take in the

height of the button, thickness of the sewing material into consideration

and

when the needle comes down to the lowest point, be careful to see

that

the

shank

the

needle

does

not

hit

the

button

itself.

INSERTING

THE

NEEDLE

(Fig. 5)

insert the needle, loosen

the

needle

clamping

screw

and

insert

the needle into the needle

bar

as far as it will go, with the long gloove

to the front and tighten the set screw securely.

Long

groove

Fig.

— 6 —

From the library of: Superior Sewing Machine & Supply LLC

thread

the machine,

put

it in stop

motion

position,

and

thread

accordance

with

the

diagram

as shown in Fig. 6, 7.

Start

from

thread

spool

stand—»

needle

thread

guide pin

No. I

♦

tension disc No. I

d)—»

tension disc

No. 2

(g)—»

thread puIl-ofTlever » nipper

(§)—•

thread guide No. 2

(6)—♦

upper eyelet of (ace

plate—»thread guide No. 3

(2)—*

needle

bar

bear

ing block

and

thread

guide

(§)—*

thread

tension

disc No. 3

thread

guide

(9)-^

tension disc No. 3

» to

the

needle eye from front

toward

rear

and

draw

the

thread

out

about

6-^7

m/m

(about

1/4").

To draw out the thread, push the nipper

releasing plunger knurled nut, @ the nipper will

released

and

the

thread

can

drawn

out.

ThreadX

int

From the library of: Superior Sewing Machine & Supply LLC

10.

THE

THREAD

TENSION

(Fig. 8)

The thread tension disc No.

Ci)

controls the tightness of the button

but only a light tension is required.

The

thread tension disc No. 2

regulates the tension of the under

sideofthe button but a stronger

tension

than the

disc

No.

1 is required.

To adjust the

tensions

these

discs,

turn the adjusting screw of the

disc toward the arrow direction to make the tension stronger

but

the

tension required will vary in relation to the types of thread, materials,

and

thickness

buttons

used.

11.

FUNCTIONS

THE

THREAD

PULL-OFF

LEVER

(Fig. 9)

@0)

The

thread pull-off lever (Fig. 6 ®) controls the amount of thread

which is pulled through the tensions at the end of a stitching cycle to

From the library of: Superior Sewing Machine & Supply LLC

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