JUNO HF3434D User manual

SERVICE MANUAL
Model HF3434D

CONTENTS
SERVICE ACCESS
FACE PLATE UNIT ............................................................................................................1
BACK COVER UNIT ..........................................................................................................2
FRONT COVER UNIT .......................................................................................................3
SIDE COVER UNIT ...........................................................................................................4
MACHINE BASE ................................................................................................................5
MECHANICAL ADJUSTMENT
MACHINE SOCKET...........................................................................................................6
NEEDLE BAR HEIGHT......................................................................................................7
PRESSER BAR HEIGHT ...................................................................................................8
FEED DOG HEIGHT..........................................................................................................9
TIMING OF THE NEEDLE AND THE FEED DOG ............................................................10
TIMING OF THE NEEDLE AND THE UPPER KNIFE .......................................................11
HEIGHT OF THE LOWER LOOPER .................................................................................12
CLEARANCE BETWEEN THE NEEDLES AND THE LOWER LOOPER
/NEEDLE GUARDS ...................................................................................................13-15
CLEARANCE BETWEEN THE NEEDLES
AND THE FIXED NEEDLE GUARD .........................................................................16
POSITION OF THE CHAINING FINGER ..........................................................................17
POSITION OF THE UPPER LOOPER ..............................................................................18
TIMING OF THE NEEDLE AND THE LOWER LOOPER ..................................................19
TIMING OF THE UPPER AND LOWER LOOPERS ..........................................................20
CLEARANCE BETWEEN THE LOOPERS........................................................................21
CLEARANCE BETWEEN THE NEEDLE AND THE UPPER LOOPER.............................22
POSITION OF THE KNIVES .............................................................................................23
POSITION OF THE LOWER LOOPER THREAD GUIDE .................................................24
STITCH LENGTH ..............................................................................................................25
THREAD TENSION DIALS ................................................................................................26
PLAY OF MAIN SHAFT .....................................................................................................27
BELT TENSION .................................................................................................................28
OILING ........................................................................................................................... 29
GAUGES FOR SERVICING .......................................................................................... 30
PARTS LIST .................................................................................................................. 31-50

1
MODEL 3434D
FACE PLATE UNIT
To remove:
1. Loosen the set screw A and remove the face plate unit.
To attach:
2. Fit the U-groove of the face plate between the setscrew A and set plate, put the rib of face
plate into the front cover unit and back cover unit and tighten the setscrew.
Setscrew A
Face plate unit
U-groove
Set plate
Back cover unit
Rib
Front cover unit
SERVICE ACCESS

2
MODEL 3434D
BACK COVER UNIT
To remove:
1. Remove setscrews A and the spool stand.
2. Remove setscrews B,C and D.
3. Remove the back cover unit.
To attach:
4. Put the ribs of back cover into the front cover unit and tighten setscrews B, C and D.
5. Attach the spool stand with setscrew A.
Back cover unit
Setscrew B
Setscrew C
Setscrew A
Setscrew D
Rib
Rib
Spool stand
SERVICE ACCESS

3
MODEL 3434D
FRONT COVER UNIT
To remove:
1. Remove setscrews A and the looper cover unit.
2. Remove the face plate unit and the back cover unit.
3. Turn the hand wheel toward you with your hand, and set the upper looper at lowest position,
and remove setscrews B, C, D,E and the front cover unit.
To attach:
4. Attach the front cover unit with setscrews B, C, D and E.
5. Attach the looper cover unit with setscrew A.
6. Attach the back cover unit and face plate unit.
Setscrew C
Setscrew D
Upper looper should be set
at lowest position
Front cover unit
Looper cover unit
Setscrew A
Setscrew E
Setscrew B
SERVICE ACCESS

4
MODEL 3434D
SIDE COVER UNIT
To remove:
1. Open the side cover unit. Remove the snap ring E-3 and pull out the shaft.
To attach:
2. Attach the side cover unit and insert the shaft and attach the snap ring.
Side cover unit
Snap ring E-3
Shaft
SERVICE ACCESS

5
MODEL 3434D
MACHINE BASE
To remove:
1. Remove setscrews A, B, C, D and two hinge screws E, and remove two base cushions F
and washers.
2. Remove the machine base.
NOTE: Do not remove the remaining two base cushions.
To attach:
3. Attach the machine base unit, and tighten setscrews A, B, C and D.
4. Attach the two base cushions F, washers, and tighten hinge screws E.
Washer (thick)
Washer
Base
cushion F
Hinge screw E
Setscrew D
Setscrew C Setscrew B
Machine base
Setscrew A
Washer (thin)
SERVICE ACCESS

6
MODEL 3434D
MACHINE SOCKET
To remove:
1. Remove the back cover unit.
2. Remove the setscrews (A, B) and the machine socket unit from the motor fixing plate.
3. Remove the two setscrews C, and pull out the cord connectors.
To attach:
4. Insert the cord connectors as shown below.
5. Attach the machine socket, and tighten the two setscrews C.
6. Attach the machine socket unit on the motor fixing plate and tighten the setscrews (A, B).
7. Attach the back cover unit.
To motor
To lamp socket
Setscrews C
Machine socket
Lamp socket lead cord
Motor lead cord
Lamp socket lead cord
Setscrews B
Setscrews A
Motor fixing plate
MECHANICAL ADJUSTMENT

7
MODEL 3434D
NEEDLE BAR HEIGHT
Correct Setting:
The distance between the tip of needle on the right and the surface of needle plate should be 11.6 to
12.2 mm when the needle bar is at the highest position.
To adjust:
1. Remove the looper cover unit, face plate unit, back cover unit and front cover unit.
2. Turn the handwheel toward you with your hand, and set the needle bar at the highest position.
3. Loosen the set screw A to adjust the height, and tighten set screw A after the adjustment is done.
4. Turn the handwheel toward you one cycle, and recheck the needle bar height.
5. Attach the front cover unit, looper cover unit, back cover unit and face plate unit.
Setscrew A
Needle bar
Surface of needle plate
Needle #14
11.6 to 12.2 mm 11.6 mm
O.L G05
MECHANICAL ADJUSTMENT

8
MODEL 3434D
PRESSER BAR HEIGHT
Correct Setting:
The distance between the surface of needle plate and bottom of presser foot should be 4.7 to
5.3 mm when the presser bar lifter is raised.
To adjust:
1. Remove the looper cover unit, face plate unit, back cover unit and front cover unit.
2. Raise the presser bar lifter and loosen set screw A.
Then adjust the presser bar height (Use the service gauge O.L G05.). The presser foot
should be parallel with the slots of the needle plate.
3. Tighten the set screw A.
4. Attach the front cover unit, looper cover unit, back cover unit and face plate unit.
Top surface of needle plate
4.7 ~ 5.3 mm
5 mm
O. L G05
To be parallel
(Direction of presser foot)
Setscrew A
Presser bar lifter
Needle
MECHANICAL ADJUSTMENT

9
MODEL 3434D
FEED DOG HEIGHT
Correct Setting:
When the presser foot is lowered and feed dogs are at their highest position, the distance between
the surface of needle plate and bottom of presser foot should be 0.75 to 0.95 mm.
To adjust:
1. Set the stitch length dial at “ 3 “ and the differential feed dial at “ 1.0 “ .
2. Remove the back cover unit.
3. Lower the presser foot and raise the feed dogs to their highest position by turning the handwheel.
4. Loosen the main & sub feed dog screws A, B (4 pcs.)
5. Push the main feed dog straight up and adjust the distance between the surface of needle
plate and bottom of presser foot to 0.85 mm (Use the service gauge O.L G05.), then tighten set
screws A (2 pcs.)
6. Turning the handwheel to get the top of the main feed dog is level with the surface of the needle
plate in the downward motion. Push the sub feed dog straight up until its top surface is to be
level with the top surface of needle plate. Then tighten the set screws B of the sub feed dog.
7. Turn the handwheel to check if the feed dog height.
8. Attach the back cover unit.
0.75 ~ 0.95 mm
Surface of needle plate
Push straight up
Setscrews B
Setscrews A
0.85 mm
O. L G05
MECHANICAL ADJUSTMENT

10
MODEL 3434D
The top surface of feed dog
The top surface
of needle plate 2 ~ 4 mm
The end of feed movement
The clearance between the bushing
and feed cam should be about 1 mm
Set screw A
Bushing
Main feed cam
O. L G05
2 mm
Setscrew B
Direction D
Direction C
TIMING OF THE NEEDLE AND THE FEED DOG
Correct Setting:
With the presser foot lowered, the top of the feed dog should be level with the needle plate at the end
of feeding movement, when the tip of the right needle is 2-4 mm above the needle plate.
Before adjustment, check if the needle bar height and the feed dog height are correct.
To adjust:
1. Set the stitch length dial at “ 3 “ and differential feed dial at “ 1.0 “ .
2. Remove the back cover unit.
3. Raise the presser foot and turn the handwheel to bring the tip of right needle 3 mm above the
needle plate in its downward motion.
4. Lower the presser foot, and loose two set screws A for the main feed cam and two setscrews B for
the sub feed cam. Turn the main and sub feed cams to adjust the feed dog position then tighten the
setscrews.
–Turn the feed cams in the direction C if the feed dog is lower than the surface of the needle
plate.
–Turn the feed cams in the direction D if the feed dog is higher than the surface of the needle
plate.
5. Be sure that the clearance between the bushing and main feed cam is about 1 mm.
Attach the back cover unit.
MECHANICAL ADJUSTMENT

11
MODEL 3434D
TIMING OF THE NEEDLE AND THE UPPER KNIFE
Correct Setting:
The upper knife timing is the same as that of the needle bar. In fact, when the needle bar is at highest
position, the upper knife should be also at its highest position.
To adjust:
1. Remove the back cover unit.
2. Loosen two setscrews A, and move the balance weight to left.
3. Loosen two setscrews B, and adjust the needle and upper knife timing.
– Turn the upper knife drive cam to the direction C when the upper knife timing is being delay.
– Turn the upper knife drive cam to the direction D when the upper knife timing is too soon.
4. Tighten the two setscrews B firmly. Move the balance weight to right.
Match the guide line on the balance weight with the one of the main shaft correctly.
Then tighten the two screws A.
5. Turn the handwheel toward you one cycle, and recheck the needle and the upper knife timing.
6. Attach the back cover unit.
When the needle bar goes up,
the upper knife goes up.
When the needle bar goes down,
the upper knife also goes down.
Direction C Setscrew B
Setscrew A
Direction D
Guide line on main shaft
Upper knife drive cam
MECHANICAL ADJUSTMENT

12
MODEL 3434D
HEIGHT OF THE LOWER LOOPER
Correct Setting:
The tip of the lower looper is 65.7 mm from the center of the lower shaft as shown below.
To adjust:
1. Set the upper knife in down position and loosen the setscrew A.
2. Turn the handwheel to get the lower looper in the left most position.
3. Set the lower looper height gauge No. 787-G02 on the lower looper shaft as shown.
NOTE: If there is not enough clearance between the lower looper unit and the lower looper thread
guide, remove the lower looper thread guide.
After the adjustment, attach the lower looper thread guide on the lower looper shaft as shown.
4. Move the lower looper up or down to match the tip of the looper with the guide line on the gauge.
5. Insert the gauge downwards into the lower looper shaft as shown.
6. Tighten setscrew A.
7. Remove the gauge and set the upper knife in up position.
Guide line of gauge
65.7 mm
(Servicing gauge
No.787-G01)
Lower looper thread guide
Lower looper shaft
Lower looper unit
Setscrew A
MECHANICAL ADJUSTMENT

13
MODEL 3434D
CLEARANCE BETWEEN THE NEEDLES AND THE LOWER
LOOPER/NEEDLE GUARDS (1 of 3)
Correct Setting:
Both right and left needles should have an equal clearance from the front edge of the opening on the
needle plate.
The standard clearance between each needle and the lower looper is 0 mm to 0.5 mm.
The standard clearance between each needle and the rear needle guard is 0 mm to 0.2 mm.
Both needles slightly touch the front needle guard in a normal condition.
1. Clearance between needles and the opening of the needle plate
To adjust:
1. Remove the looper cover unit, face plate unit, back cover unit front cover unit and presser foot.
Replace the #14 needles with #11 needles.
2. Attach the needle gauge #787-G02 as shown to prevent change of needle bar height during the
adjustment.
Loosen the set screw C. Turn the needle bar in the direction D or E to get an equal clearance
between needles and the edge of the opening of the needle plate while pushing up the needle bar
to prevent a change of needle bar height.
Retighten the set screw C and remove the needle gauge.
Needle clamp
Setscrew C
Needle bar lower bushing
No clearance
Needle gauge
(787-G02)
Lower looper
Needle
(D)
(E)
Needle (R)
Equal clearance
Needle plate
Needle (L)
MECHANICAL ADJUSTMENT

14
MODEL 3434D
CLEARANCE BETWEEN THE NEEDLES AND THE LOWER
LOOPER/NEEDLE GUARDS (2 of 3)
Rear needle guard
Lower looper
Front needle
guard
Hexagonal bolt (B)
Lower looper base
Needle #11
0 to 0.05 mm
Lower looper
Front needle
guard
Hexagonal socket
scerws (A)
Set screws (F)
Rear needle guard
2. Clearance between needles and the lower looper
1. Remove the left needle only.
2. Turn the handweel towards you to bring the tip of the lower looper from the left hand to the rear side
of the right needle.
3. Loosen the hexagonal socket screws A on the front needle guard and move it away from the
needle.
4. Next, loosen the hexagonal bolt B, and slide the lower looper base back or forth along the lower
looper shaft to get the clearance between the right needle and the lower looper.
The clearance should be 0 mm to 0.05 mm.
Retighten the hexagonal bolt B.
MECHANICAL ADJUSTMENT

15
MODEL 3434D
CLEARANCE BETWEEN THE NEEDLES AND THE LOWER
LOOPER/NEEDLE GUARDS (3 of 3)
3. Clearance between needles and the rear needle guard
1. Change the right needle from #11 to #14.
2. Push the front needle guard against the needle to get the clearance between the needle and
the lower looper. The clearance should be 0 mm to 0.05 mm.
3. Attach #14 needle on the left and turn the handwheel towards you to check the clearance between
the left needle and looper. Tighten the hexagonal socket screws A.
Make sure the front needle guard is touching the needle slightly and the rear needle guard is not
touching the needle.
4. Check the timing between the needle and the lower looper.
5. Recheck the needle bar height and the clearance between the needle and the lower looper.
Needle #14
0 to 0.05 mm
Lower looper
Rear needle guard
Front needle guard
0 to 0.2 mm
(Rear needle guard is not touching the needle.)
Front needle guard
Rear needle guard
Hexagonal
socket
acrews (A)
MECHANICAL ADJUSTMENT

16
MODEL 3434D
Fixed needle guard details
CLEARANCE BETWEEN THE NEEDLES AND THE FIXED
NEEDLE GUARD
Correct Setting:
The clearance between needle and the fixed needle guard should be 0.1 to 0.4 mm.
To adjust:
1. Remove the presser foot and the needle plate and lower the needle to its lowest position.
2. Loosen the setscrew A and adjust the position of the fixed needle guard.
3. Tighten the setscrew A.
4. Attach the needle plate and the presser foot.
Needle plate setting knob
Chaining finger
Fixed needle guard
No gap
The clearance between the needle
and fixed needle guard
Fixed needle guard
Needle #14
0.1 ~ 0.4mm
Setscrew A
Needle plate setting knob should be at “S”.
MECHANICAL ADJUSTMENT

17
MODEL 3434D
POSITION OF THE CHAINING FINGER
Correct Setting:
There should be no gap between the chaining finger and the side of needle plate, and tip of chaining
finger should be the same level with the tip of the needle on the needle plate when the needle plate
setting knob is set at “S”.
To adjust:
1. Remove the presser foot.
2. Set the needle plate setting knob at “S”.
3. Loosen two setscrews A, and move chaining finger unit to the correct position.
4. Tighten two setscrews A.
5. Shift the needle plate setting knob from “S” to “R” and vice versa, then check the position of
chaining finger.
6. Attach the presser foot.
To be touched
Needle plate setting knob
Guide line S
Guide line R
Chaining finger unit
Setscrew A
Should be same level
MECHANICAL ADJUSTMENT

18
MODEL 3434D
POSITION OF THE UPPER LOOPER
Correct Setting:
The clearance between the bottom of the upper looper and the upper looper shaft guide should be 1.6
to 1.8 mm when the upper looper is at its lowest position.
The distance between the center of needle on the right and the center of looper eye should be 4.8 to
5.2 mm when the upper looper is at its leftmost position.
To adjust:
1. Remove the machine base. Turn the handwheel to bring the upper looper to its lowest position.
2. Loosen the hexagonal socket screws A, and move the upper looper shaft up or down to adjust the
clearance between upper looper shaft guide and bottom of upper looper. The distance should be
1.6 to 1.8 mm as shown in Fig. 1.
3. Tighten the hexagonal socket screws A.
4. Turn the handwheel to bring the upper looper to the leftmost position.
5. Loosen the hexagonal socket screw B, and slide the upper looper to adjust the distance between
the center of needle and center of upper looper eye as shown in Fig. 2 and Fig. 3.
6. Tighten the hexagonal socket screw B.
7. Check the upper and lower loopers timing and clearance between upper and lower loopers.
1.7 mm
O.L G05
Needle on the right
5 mm
4.8 to 5.2 mm
(Fig. 2)
Upper looper
Hexagonal socket screw B
(Fig. 3)(Fig. 1)
Upper looper shaft
Upper looper shaft guide
Upper looper
1.6 to 1.8 mm
Hexagonal socket screws A
MECHANICAL ADJUSTMENT