Bernina 730 Manual - Page 76

d)

needle

of

inferior

quality

or

badly

polished;

e)

size

of

needle

and

size

of

thread

are

not

in

good

relation

together.

5.

Needle

breaking

may

have

the

following

causes:

a)

needle

holder

screw

not

securely

tightened;

b)

upper

thread

tension

too

tight;

c)

the

material

has

been

pulled

from

under

the

pres-

ser

foot

towards

the

front,

after

having

finished

with

the

sewing

work.

Thus

the

needle

got

bent.

Always

remove

the

material

from

the

machine

by

pulling

it

back

from

under

the

presser

foot

base;

d)

size:of

needle

and

size

of

thread

are

not

in

correct

relation

together.

Often

the

needle

is

too

thin

for

too

thick

a

yarn,

whereby

the

needle

becomes

bent;

e)

use

of

thread

of

inferior

quality,

unevenly

twisted,

or

having

knots;

f)

during

sewing

do

not

pull

the

material

too

hardly

towards

the

back.

6.

Faulty

seams

a)

A

faulty,

uneven

seam

is

formed:

1.

if

there:are

ends

of

threads

between

the

thread

tension

discs;

2.

if

there

are

thread

ends

under

the

bobbin

ease

tension

spring;

3.

if

the

bobbin

is

deformed

and

jamming

in

the

bobbin

case;

4.

if

the

thread

is

not

evenly

manufactured;

5.

if

the

shuttle

is

not

oiled;

b)

when

sewing

tricot

of

other

knit

goods

make

sure

of

the

following

items:

1.

tricot

should

always

be

basted

with

darning

thread,

never

with

basting

thread;

2.

use

perfect

needles

of

size

no.

70

or

80;

3.

the

thin

area

of

the

material

should

be

placed

to

the

left

under

the

presser

foot;

4.

sizes

of

needles

and

thread

should

be

in

per-

fect

relation

together;

5.

if

the

zigzag

stitch

seams

not

to

be

elastic

enough,

adjust

for

a

larger

width

and

a

shor-

ter

stitch

length

in

order

to

enlarge

the

elasti-

city

of

the

seam;

c)

puckered

seams:

in

most

cases

the

cause

of

puckering

is

too

tight

a

tension

on

upper

and

under

thread.

When

sew-

ing

tricot

and

other

knit

goods

the

material

must

never

be

pulled

to

the

back

with

the

hands;

other-

wise

the

seam

gets

puckered.

Care

has

to

be

taken

74

Bernina 730 Manual - Page 76

Needle, breaking, Faulty, seams

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