Pfaff hobbyblock 794 User manual

74
0
Instruction
manual
I

Notes on safety
A) Due to the up
and down movement of
the needle, the
user
must take
sufficient care to avoid
injury and
observe the sewing
area continuously
while sewing.
B) When leaving the
machine,
changing parts or accessories,
the
machine must
be
disconnected
from the power source.
C)
The maximum approved wattage
of
the
light bulb
is
15 watts.
D) The drive belt must never be adjusted
by
anyone but an authorized Pfaff
agent.

Contents
The
controls of
the
sewing
machine
2, 3
Accessory
box
4
Electrical
connection
4,
5
Foot
control
5
Preparing
for
threading
6, 7
Threading,
4-thread
double-overedge
seam
7—11
Threading
right
looper
8
Threading
left
looper
9
Threading the
needles
10
Inserting the
lint
box
11
Sewing
test
12
Points to
observe
during
sewing
13
Securing
the
seam
14
Checking
and
adjusting
thread
tension
15, 16
3-thread
overedge seam
17
Thread chart
18
Adjusting
the
stitch length
on 794
18
Adjusting
the
stitch length
on
796
19
Adjusting
the
differential
feed
on
796
20,21
Regulating
the
sewing foot
pressure
18
Adjusting
the
seam
width 22
Changing
the sewing
feet
23
Sewing
rolled
hems
24,
25
Changing
needles
26
Changing
lower
knife 26, 27
Changing
upper
knife
28
Changing
light
bulb
29
Cleaning
the
thread
tensions
29
Oiling the
machine
30
Sewing
problems and
solutions
31
Accessories
32
Specifications
32

C,’

Controls of the
sewing machine
1 Foot
pressure regulating
dial
2
Thread guide
3
Carrying
handle
4 Left needle thread
tension dial
5 Right
needle thread
tension
dial
6
Right
looper
thread tension dial
28
7 Left looper
thread tension
dial
cover
///
2
11
Presser foot
lifter lever
-- /
12 Hand wheel
and feed regulator
13 Looper
cover
26
‘N
14 Looper
cover lever
15 Work support
16
Stitch length
setting key on
794
Differential feed
setting on 796
17 Needle plate
18
Presser foot
19 Needle bar
20 Thread
reel stand
27
21 Thread
reel pins
22 Adjusting knob
23
Machine plug
socket
24 Master switch
_______________________________________
25 Lint
box
26 Foot control
27 Foot control
plug
28 Mains plug
29 Lower
knife
30
Knife
clamp screw
9
31
31 Right looper
32 Left
looper
33
Thread guide
bar
32
30
if
29
I

Accessory
box
Electrical
connection
Use this
machine
only on
a
flat
surface
or on a
special
sewing
table.
Attaching
the
toot
control:
Insert the
plug
of
the
control
into
the
machine
plug socket.
Then
connect
the
mains
plug
to
a
power
source.
Caution:
When
the
machine
is
not
in
use,
disconnect
plug
from power
source.
Do
not
place any
objects
on the
foot
control.
Swing
the
work support
to
the left
and
pull
out
the
accessory
box.
To
replace
the accessory
box,
slide
it
into
the
grooves
and
push
it
until it
locks. The
accessories
are
illustrated
on
page
32.

Foot
Control
The
speed
of
the
HObbyIo
is
regula
as
follows:
When
press,g
the foot
Control
gently
the machine will
run at
low
Speed.
when
Pressing
harder
it
will
run
faster.
Electronic
foot
control
Maximum
speed
is
adjusted
in
two
grad 5
by
the
switch
on
the
foot
control
Pos,ho,,
=
Half
Speed
Posillon
4 =
Full
speed
Switching
the
machine
ON and
OFF
Power
and
sewing
light
are
switched
on
and
off
simultaneously
with
the
master
Switch
SWitching
on:
Press
switch.
Machine
and
sewing
light
are
switched
on.
Switching
off:
Press
switch
again.
Machine
and
sewing
light
are switched
off.

Preparing
for
threading
Adjustment
of
thread
reel
stand:
Loosen
the
adjusting
knob
on
the
thread
reel
stand,
slide
it
to the
left
and
tighten
it.
Adjustment
of
the
thread
guides:
Pull
up
the
thread
guide
bar
and
align
it
j
so
that
the
thread guides are
directly
above
the
reel
stand.
JL_L_LjjJ
L
N
Carrying
handle and
thread
guide bar
behind
it:
\
Insert
fingers into
the
groove
of
the
carrying
handle and
pull
it
up.
This
movement
automatically
raises
the
zr’
thread
guide
bar

Opening and
closing
looper cover
and
work
support
Push
looper
cover
lever
to
the right,
swing
cover
in
the
direction
of the
arrow
and
lower
it.
To
close
the
looper cover,
push
the
cover
until
it locks.
To
open
the work
support, push
it
to the
left.
To
close
the
work
support, push
it
to
the
right
until
it locks.
A threading
diagram
is affixed
to the
machine
(A).
Threading
procedure
Threading must
be
done
correctly to
obtain
a well-formed
seam.
Thread
the
machine
in
the following
sequence:
1. Right
looper
(red)
2.
Left
looper
(orange)
3.
Right
needle
(green)
4.
Left
needle
(blue)
Diagram
B shows
threading
of
the
thread guides behind
the
carrying
handle.
Diagram
C shows
threading
of
the
thread
tension.
Now pull
the
respective thread
into
the
corresponding guides
and
tension
discs.
7

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Threading
the
left
looper:
Insert
the
left
looper
thread
in
sequence
1
to
10
and
pull
approximately
10
cm
(4)
of
thread
through the
looper
eye
(the
thread
path
is
marked
orange).
0

Threading the
right
needle:
Thread
the
right
needle
in
sequence
1
to
7 and
pull
approximately 5
cm of
thread
through the eye
of
the needle.
(The
thread
path
is marked
green.)
Make
sure
to
thread
point
4 with
special
care;
insert
the
thread
behind
hook
A
of
the
thread
guide
plates
fitted
on both
sides.
Threading the
left
needle:
Thread
the
left
needle
in sequence
1
to 7 and
pull
approximately 5
cm of
thread
through
the
eye
of the
needle.
(The
thread
path is
marked
blue.)
Make
sure
to thread
point
4 with
special
care;
insert
the
thread
behind
hook
A of
the
thread
guide
plates
fitted
on
both
sides.
The
diagram
shows
the correctly
threaded
machine.

Now
close the
work
support
(1),
push
the
handle
down
(2)
and
close the
looper
cover
(3).
Inserting the lint
box:
Insert
the tabs
of the
lint box into
the
slots
(4) of
the front
cover.
Push the
lint
box up
against
the
front
cover
until it
snaps
in place.
Use the
reverse
order
to
remove
lint
box.
11

Sewing
a
test
sample
After
threading,
a
test sample
should
be
sewn.
Raise
presser
foot
lever,
as
shown
in
illustration.
Insert
test
fabric
and
lower
presser
foot.
Hold
thread
ends
with
your
left
hand
while
turning
hand
wheel
counter
clockwise
with
your
right
hand.
In
doing
so,
the
threads
must
be
guided
to
the
rear,
under
the
presser
foot.
Make
sure
that
threads
have
interlocked
correctly.

Points
to
observe
during sewing
Place the
fabric
completely
under
the
presser
foot
when
starting
to
sew.
(Also
after
the
machine
has
been
re
threaded).
Sew
the
first
stitches
slowly.
Since the
fabric
is
fed
automatically,
do
not
pull
or
push
the
fabric.
Use
your
hand
for
guiding
only.
Finishing
seam
Sew approximately
5
cm beyond
the
end
of
the
seam
and
use
the
thread
cutter
(1)
behind the
presser
foot to
cut
the
thread
chain.

Securing
the
seam:
Knot
the
thread
chain. For
knit
fabrics,
a
crochet
needle can
be
used
to
pull
the
thread chain
into
the
seam.
To
prevent
ravelling
of
seams,
sew
approximately
3
cm
(1”)
beyond the
seam.
Raise
presser
foot. Flip
fabric
over.
Lower
presser
foot
and
sew
over
the
seam
approximately
2
cm
(1/2’)
without
cutting
the
chain.
Sewing
very
heavy fabrics
and
different
thicknesses
of fabric:
This
machine
will
sew
through
very
thin
to
very
heavy
fabrics.
When
sewing
very
heavy
fabrics,
tighten
the
upper
knife
screw.
Note:
When sewing
thin
fabrics,
loosen
the
upper
knife
screw
after
sewing
on
heavy
fabrics.
(See
illustration).

Top
side
Setting
thread
tensions:
Right
looper
thread
Left
-
looper thread
Right
-
I
Left
needle
thread
Reverse
side
needle
thread
The
thread tension should
be
adjusted
according
to
fabric
type
and thread
size.
Examine
the
seam
and make
the
necessary
tension
adjustments.
Adjusting
thread
tension:
Set
all
thread
tension
dials
to
“N”
(standard
setting).
See
illustration
below.
Sew
a
test
sample
to
be
sure
that
the
correct
tension
has
been
obtained.
See
illustration
above.
1

When
the
thread
tension
is
turned
in
(+)
direction,
the
tension
is increased.
When
turned
in
(—)
direction
it
is
decreased.
Incorrect
thread
tension;
The
left
needle
thread
is
too
loose
(blue
thread
tension).
The
right
needle
thread
is
too
loose
(green
thread
tension).
The
right
looper
thread
is
too
tight
(red
thread
tension)
or
the
left
looper
thread
too
loose
(orange thread
tension).
Top
side
Reverse side
1
-
The
left
looper
thread
is too
tight
(orange
thread
tension)
or
the
right
looper
thread
too
loose
(red
thread
tension).

3-thread
overedge
seam
How
to
convert
from
four-thread
to
three-
thread
sewing:
Three-thread
sewing
is
possible
by
using
either
right
or
left needles (see
page
10).
Remove
the
needle
that
is
riot
used
(see
page
26).
3-thread
overedge seam
Needle
thread
Left
needle
Rht
needle
Thread tension
Marked
blue
Marked
green
Thread
in
needle
clamp
guides
_____
00
Standard
seam
width
maxim
urn
seam
width
6.5
mm
4.5
mm

Thread chart
Material
Thread
Stitch
length
Light
materials:
Organdy,
light-knit
Cotton
No. 80—100
2.0
to
4.0
mm
fabric,
Taffeta,
silk, Silk
No.
80—100
lining materials. Synthetic
thread
No.
70—140
Medium-heavy
materials:
Cotton
No. 60—100
2.0
to 4,0
mm
Cotton,
tricot,
Silk
No.
50—100
linen, dress
materials
Synthetic
thread
No.
70—140
Heavy
materials:
Tweed,
suit
Cotton
No.
40-60
2.0 to
4.5 mm
materials,
Silk
No.
40—60
denim,
heavy
cloth
Synthetic
thread
No.
70—140
Knit
fabrics: Cotton
No,
40—60
2,0
to 4.5
mm
Silk No.
40—60
Synthetic
thread
No.
70—140
Rolled
hem
Polyester
thread
No. 120/2
(180) 1.5
to 2.5
mm
Mercerized
thread
(bulk
thread)
Sewing foot
pressure:
Position
N”
of the
foot
pressure dial is
the
standard
sewing
foot
pressure.
It is
normally
reset
only
for very
thin or
heavy
fabrics.
Thin
fabrics:
Reduce
the
sewing
foot
pressure
by
setting
to a
lower number.
Heavy
fabrics:
Increase
the
sewing
foot
pressure
by
setting
to a
higher
number.
Stitch Ienght
setting
on 794
The
stitch
length
is regulated
by turning
feed
regulator
16.
The
numbers
indicate
the
stitch
length
in mm
which normally
is
N
(3
mm).
A
= setting
mark.