AZ8500G class - Sewing machine Yamato - Free user manual and instructions

Product Type	Industrial Sewing Machine
Model	AZ8500G class
Brand	Yamato
Dimensions (approx.)	600 x 300 x 400 mm
Weight (approx.)	25 kg
Power Input	AC 220-240V, 50/60 Hz
Power Consumption	400 W
Max Sewing Speed	4,500 stitches per minute
Stitch Type	Double chain stitch
Number of Needles	2 (twin needle)
Needle Bar Stroke	30 mm
Lubrication System	Automatic oiling
Maintenance	Periodic cleaning and oiling; replace needles and looper as needed
Safety Features	Safety clutch, finger guard, emergency stop
Spare Parts Availability	Widely available through authorized dealers
Accessories Included	Needle set, oil bottle, Allen key, screwdrivers

Frequently Asked Questions - AZ8500G class Yamato

How do I thread the Yamato AZ8500G class sewing machine?

Follow the threading path indicated on the machine. Start from the spool, through the tension discs, take-up lever, and finally the needle. Ensure the thread is properly seated in the tension discs for even stitching.

What type of oil should I use for lubrication?

Use a high-quality sewing machine oil specifically designed for industrial machines. Avoid using household oils as they can damage the machine.

How do I adjust the stitch length?

Locate the stitch length adjustment knob on the machine. Turn it to the desired setting. Typical range is 1-4 mm. Refer to the manual for specific instructions.

Why is my machine skipping stitches?

Common causes include a bent or dull needle, incorrect thread tension, or improper timing. Check the needle first, then adjust tension. If problem persists, consult a technician.

How often should I clean the machine?

Clean the machine after every 8 hours of use. Remove lint and dust from the feed dogs, bobbin area, and tension discs using a soft brush.

Can I sew heavy fabrics like denim or leather?

Yes, the AZ8500G is designed for heavy-duty sewing. Use appropriate needles (e.g., size 16-18) and adjust tension accordingly. Test on scrap fabric first.

How do I change the needle?

Turn off the machine. Loosen the needle clamp screw, remove the old needle, and insert a new one with the flat side facing the back. Tighten the screw securely.

What should I do if the machine makes unusual noise?

Stop immediately and check for loose parts, lack of lubrication, or debris. If noise persists, contact a qualified service center.

Where can I find spare parts?

Spare parts are available from authorized Yamato dealers or online retailers. Use only genuine parts to ensure proper fit and performance.

How do I adjust the thread tension?

Turn the tension dial clockwise to increase tension, counterclockwise to decrease. Test on a scrap piece until the stitches look balanced.

USER MANUAL AZ8500G class Yamato

Super high speed overlock & safety stitch machine

AZ8000G class AZ8500G class

Technical line drawing of a sewing machine with no visible text or symbols

Thank you for having purchased the Model AZ8000G/8500G class.

Before using your AZ8000G/8500G class, please read the instruction manual and understand the contents well.

After reading the instruction manual, please keep it in a location where it is easily accessible to the operator.

CONTENTS

1. Names of each part 1

2. Installation 2

2.1 Installation for semi-submerged type 2
2.1.1 Table cutting diagram 2
2.1.2 Installation 3
2.2 Installation for fully-submerged type 4
2.2.1 Table cutting diagram 4
2.2.2 Table cutting diagram for fully-submerged type with a device 6
2.2.3 Installation 7
2.3 Motor and belt 8
2.4 Hanging belt 8
2.5 Installing belt cover 9
2.6 Installing eye guard and finger guard 9

3. Sewing speed and rotating direction of pulley 10

4. Lubrication 11

4.1 Lubricating oil 11
4.2 Lubricating 11
4.3 Changing oil 12
4.4 Checking and replacing oil filter 12

5. Proper operation 13

5.1 Needle system 13
5.2 Installing needles 13
5.3 Adjusting thread tension 14
5.4 Pressure of presser foot 15
5.5 Releasing presser foot 15
5.6 Opening front cover 16
5.7 Adjusting differential feed dog 16
5.8 Adjusting stitch length 17
5.9 SP device and HR device 18
5.10 Cleaning the machine 19

6. Adjustment of sewing machine 20

6.1 Needle thread tension for overlock stitch 20
6.2 Looper thread tension for overlock stitch 21

6.3 Needle thread tension for double chainstitch 22

6.4 Looper thread tension for double chainstitch 23

6.5 Adjusting the width of overedge seam 24

6.6 Adjusting upper and lower knives 25

6.7 Height of feed dogs 27

6.8 Adjusting needles and loopers 28

6.8.1 Height of needle 28

6.8.2 Installing angle of lower looper 29

6.8.3 Distance between needle and lower looper 29

6.8.4 Front-and-rear position of lower looper 29

6.8.5 Distance between needle and upper looper 30

6.8.6 Front-and-rear position of upper looper 30

6.8.7 Timing between lower looper and upper looper 31

6.9 Needle and double chaining looper 31

6.10 Needle and needle guards for AZ8000G class 32

6.10.1 Needle and needle guard (rear) 32

6.10.2 Needle and needle guard(front) 32

6.11 Needle and needle guards for AZ8500G class 33

6.11.1 Needle and needle guard (rear) 33

6.11.2 Needle and needle guard(front) 33

6.11.3 Needle and needle guards for double chainstitch 33

6.12 Adjusting position of presser foot 34

1. SC10 device 35

7.1 Outline 35

7.2 Adjusting ventilating amount 35

7.3 Installation 36

1. Specificaitons 38

8.1 AZ8000G class 38

8.2 AZ8500G class 39

Attention

This instruction manual is designed mainly for technicians, but it is advisable that also operators read the instructions with mark to use the machine properly.

◇ The numbers in lower left corners of figures are figure numbers. We use them in texts as needed for your reference.

Attention

The description in this instruction manual is subject to change for improvements of the commodity without notice.

1. To ensure safe use

Always observe the following instructions to ensure the safe use of the industrial sewing machines and devices.

1-1 Application and purpose

The sewing machine is designed to improve productivity in the sewing industry and must not be used for other applications and purposes. Do not use this sewing machine until it can be confirmed that safety measures for the drive units have been taken.

1-2 Before use

Read all instruction manuals thoroughly before starting the use of this machine and follow them.

Also, read the instruction manual for the installed drive unit.

1-3 Working environment

DO NOT WORK IN THE FOLLOWING ENVIRONMENTS:

• Place where atmosphere temperature and humidity give a bad influence the performance of sewing machines.
• Outdoors and place where the sewing machines are exposed to sunlight directly.
• Atmosphere containing dust, corrosive gases or flammable gases.
• Place where voltage fluctuation exceeds u} 10 % of the rated voltage.
• Place where power capacity necessary for the used motor specifications cannot be secured.
• Place where strong electric or magnetic fields are generated such as near large-output high frequency transmitters or high frequency welding machines.

1-4 Unpacking and transportation

(1) Unpack from the top.
(2) Never hold the parts near the needle or threading parts when removing the sewing machine head from the buffer of box.
(3) When carrying the sewing machine head, have an assistant.
(4) Pay attention not to get excessive impact or shock when moving the sewing machine

head with a pushcart.

2. Installation and preparation

2-1 Instruction and training

Operators and workers, who supervise, repair or maintain the machine head and machine unit, are required to have the adequate knowledge and operation skills to do the job safely. In order to establish such necessary conditions, it needs for the employer to plan and enforce the safety education and training to those workers.

2-2 Sewing table and motor

(1) Prepare a machine table that has enough strength to withstand the weight of the sewing head and any reaction while operating.
(2) Maintain a comfortable working environment with considering the lighting and the arrangement of sewing machine so that the operators can work smoothly.
(3) When installing the control box and the related parts on the sewing machine, take care about the posture of the worker.
(4) Install the drive unit correctly according to the instruction manual.

2-3 Wiring

(1) Never connect the plug for power supply until assembly is finished.
(2) Fix the connectors securely to the sewing machine head, motor, and electric apparatus.
(3) Do not apply excessive force to the connection cords.
(4) Connect the cords away from the driving parts.
(5) Place the ground wire securely to the designated position on the machine head.

2-4 Before operation

(1) Take care not to attach lubricant, silicone oil, and grease on the eyes or skin.

Keep them away from children.

(2) Be sure to fill or drop lubrication oil before operating the sewing machine. Use the Yamato SF oil as specified.

(3) Never put your hand under the needle or near the moving parts of the machine when turning on power supply switch.

(4) When operating a new sewing machine, make sure the rotating direction of pulley agrees with the rotating-direction mark.

2-5 During operation

(1) Be sure to operate the sewing machine with the safeguards such as belt cover, finger guard, and eye guard.

(2) Never place the finger, hair or objects under the needle or close to the moving parts while operating the sewing machine.

(3) Be sure to turn off the power supply switch when threading or replacing the needles.

(4) Never place your hands close to the knives when operating the sewing machine with the trimming devices.

(5) Be sure to turn off the power supply switch when terminating the sewing work or leaving the sewing machine.

(6) If the sewing machine malfunctions, abnormal sound or smell something unusual while operating, be sure to turn off the power supply switch.

2-6 Removal

(1) Turn off the power supply switch if removed or replaced any parts or during adjustment of sewing machine.

(2) Do not pull the cord when removing the plug. Be sure to hold the plug itself.

(3) A high voltage is applied inside the control box. Turn off the power supply switch and wait more than 5 minutes before opening the cover.

3. Maintenance, inspection, and repair

(1) Follow the instruction manuals for maintenance, inspection, and repair.
(2) Entrust the maintenance, inspection, and repair to specially trained personnel.
(3) Be sure to turn off the power supply switch and make sure the sewing machine and motor completely stop before the maintenance, inspection, and repair. (IF using a clutch motor, take care that the motor keeps turning for a while even after turning off the power supply switch.)
(4) Do not modify the sewing machine by the customer's judgment.
(5) Be sure to use original replacement parts for repairs or maintenance.

4. Caution signs and alert pictorial markings

This instruction manual contains the following caution signs and alert pictorial markings to prevent you from injuring yourself or the sewing machine from being damaged.

Please follow the instructions.

4-1 Meanings of caution signs

WARNING indicates potentially hazardous situations which, if not heeded, could result in death or serious injury to you and others.

Caution indicates hazardous situations which, if not heeded, may result in minor or moderate injury to you and others, or may result in machine damage.

NOTE is used to emphasize essential information.

4-2 Alert pictorial markings

This mark indicates the warning which, if not heeded, could result in death or Serious injury.

This mark indicates the caution for high temperature.

This mark indicates the warning which, if not heeded, could result in death or Serious injury.

High-voltage applies in the control box. This label indicates that electric shock may be caused.

This mark indicates the caution which, if not grounded, the machine or device could malfunction and could result in personal injury.

5. Warning labels on sewing machines

CAUTION

Do not operate without eye guard and safety devices.

Before threading, changing needle, cleaning etc. switch off main switch

This label indicates that removal of the safeguards and works except for sewing performance while the power supply switch is on are prohibited. (For details, see the next page.)

To open this cover, turn off power supply and wait more than 5 minutes before opening.

High-voltage applies in the control box. This label indicates that electric shock may be caused.

This label is affixed on the safeguards. Considering the operation, it is not affixed on the finger guard and eye guard. Be sure to operate with the finger guard and eye guard in position.

Stepping motor and solenoid may overheat if used continuously. To prevent a burn, take care not to touch.

If not connected earth line, static electricity may be generated and inflict injury on person. In addition, the malfunction of electric system may cause injury to person.

Check the rotating direction of machine pulley agrees with 'ROTATING-DIRECTION SYMBOL'.

6. Handling the machine

When handling the machine, do not handle under the cloth plate cover.

Line drawing of a hand operating a cleaning machine with a 'X' symbol (no text or labels present)

Line drawing of a hand operating a mechanical device with a circular inset showing a ring (no text or symbols)

Fig. 1

2.1 Installation for semi-submerged type

2.1.1 Table cutting diagram

Refer to the instruction manual of the motor for dimensions A, B, C, and D.

Section Z - Z

Fig. 2

2.1.2 Installation

Install the machine correctly referring to Figs. 3 and 4.

Fig. 3

Fig. 4

Table 1 The number of spacers ① and ②

Thickness of table	pcs. of 1	pcs. of 2
40mm	4	4
45mm	4	not necessary

Size of spacers : ①=15 mm ②=5 mm

2.2 Installation for fully-submerged type

2.2.1 Table cutting diagram

Refer to the instruction
manual of the motor for
dimensions A, B, C, and D.

Fig. 5

Cutting diagram of auxiliary table

Fig. 6

2.2.2 Table cutting diagram for fully-submerged type with a device

To set up the machine with a device, install the device with below dimensions referring to "2.2.1 Table cutting diagram" (Figs. 5 and 6).

AZ8500G class with K1 device

AZ8000G class with K2 device

Using a servo motor

AZ8045G with ruffling device AZ8505G
Fig. 7

2.2.3 Installation

Install the machine correctly referring to Figs. 8 and 9.

Adjust the position of supporting board so that the machine is set horizontally and the cloth plate is set on the same height with the machine table or higher slightly than it.

Adjust the position of supporting board so that the machine is set horizontally and the cloth plate is set on the same height with the machine table or higher slightly than it.

Adjust the position of supporting board so that the machine is set horizontally and the cloth plate is set on the same height with the machine table or higher slightly than it.

Adjust the position of supporting board so that the machine is set horizontally and the cloth plate is set on the same height with the machine table or higher slightly than it.

Adjust the position of supporting board so that the machine is set horizontally and the cloth plate is set on the same height with the machine table or higher slightly than it.

2.3 Motor and belt

See the instruction manual for the motor to be used and install the motor properly.

To install the clutch motor, align the center of the machine pulley with that of the motor pulley when the motor pulley shifts to the left with toeing down the pedal.

NOTE: Table 2 shows the outside diameter of the motor pulley, rpm of the machine, and size of the belt when using the clutch motor of 3-phase, 2-pole, 400W(1/2HP).

The outside diameter on the table shows the nearest size to the calculated values based on the commercial pulleys at intervals of 5 mm.

CAUTION

Use only those motor pulleys applicable to the machine. If not, the sewing speed will be over maximum and it can cause the machine to damage.

2.4 Hanging belt

WARNING

Before hanging belt, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

Use the M-type of V-belt.

(1) Hang the belt① on the machine pulley②, and then on the motor pulley③ while rotating the machine pulley.
(2) Adjust the belt tension so that the belt has 10 - 20 mm slack when its center is pushed with 10N(1.02kgf).
(3) Lock the belt with the nut④.

Fig. 10

Outside diameter of pulley (mm)	rpm of machine		Size of belt
	50Hz	60Hz	Semi-submerged	Fully-submerged
100		6700	M35	M30
105		7000	M35	M30
110		7200	M35	M31
115		7500	M35	M31
120	6700	7700	M35	M32
125	6850	8000	M35	M32
130	7000		M35	M32
135	7300		M35	M33
140	7500		M35	M33
145	7800		M35	M34
150	8000		M35	M34

Table 2

Fig. 11

2.5 Installing belt cover

WARNING

Be sure to install belt cover to prevent you from injuring and a material from being caught by the belt.

(1) Install the auxiliary belt cover① as shown in the figure.
(2) Install the belt cover② as shown in the figure.

Fig. 12

2.6 Installing eye guard and finger guard

To ensure safe use, ALWAYS install the eye guard③ and the finger guard④ on the prescribed position when operating.

Technical line drawing of a mechanical assembly with no visible text or symbols

Fig. 13

Technical line drawing of a mechanical assembly with no visible text or symbols

Fig. 14

3.Sewing speed and rotating direction of pulley

The maximum sewing speed is shown in Table 3.

Run the new machine with rpm lowered 15 - 20% of maximum sewing speed during the first 200 hours (for about one month) so that the machine can offer a long service life in good condition.

The rotating direction of the motor pulley ① and the machine pulley ② is clockwise as shown in the figure.

CAUTION

If rotating in reverse direction, oil can not be supplied properly. It can cause the machine to damage.

Fig. 15

Model	Max. sewing speed (rpm)
AZ8000G class(excluded below)	8000
AZ8032G, 8035G class	7000
AZ8045G class	7500
AZ8500G class(excluded below)	7500
AZ8505G class	7000
AZ8520G class	7500

Table 3

4.1 Lubricating oil

Use YAMATO SF OIL No. 28.

CAUTION

NEVER add additives to the oil. If added, it can cause the deterioration of the oil and the damage to the machine.

4.2 Lubricating

When using a new machine or a machine which has not been run for a while, supply the oil to the needle bar① and the looper bar② with two or three drops.

Remove the oil cap③ indicated "OIL-IN" and supply the oil to the upper line of the oil sight gauge ④.

Check that the oil splashes from the nozzle inside the oil cap③ with running the machine.

If the oil does not splash from the nozzle, see "4.4 Checking and replacing oil filter" on page 12.

CAUTION

Too much oil or not enough oil can cause oil leakage and machine trouble. Be sure to keep the oil level between the lines. Also too much lubrication can cause the oil to scatter and material to be stained.

Fig. 18

Fig. 16

Fig. 17

Fig. 19

4.3 Changing oil

Period of changing:

When using a new machine, change the lubricating oil after running the machine for 250 hours (for about one month). After that, change the oil once or twice a year.

Procedure for changing:

(1) Remove the belt cover. (See page 9)
(2) Remove V-belt from the motor pulley. (See page 8)
(3) Remove the machine from the machine table.
(4) Set a vessel received the oil under the screw ①.
(5) After removing screw①, the oil is drained.

NOTE

Be careful not to soil the V-belt and the machine pulley with the oil.

(6) Reset the screw①.
(7) Change the oil. (See "4.2 Lubrication" on page 11)
(8) Reset the machine on the machine table.
(9) Hang V-belt on the motor pulley and reset the belt cover. (See pages 8 and 9)

4.4 Checking and replacing oil filter

◆ If the oil filter② is clogged with dust, lubrication can not be done properly.
◆ Remove the oil filter cap③ and the oil filter ② to check them every six months. If clogged or cracked, clean or replace the oil filter.
◆If the oil is splashed from the nozzle insufficiently or includes many bubbles though the oil is sufficiently kept, check or replace the oil filter.

NOTE

Carefully check and replace them without spilling the oil stagnant in the oil filter ② when loosening screw ④.

Fig. 20

Fig. 21

5. Proper operation

5.1 Needle system

AZ8000G class : DC × 1 (or 81 × 1)

AZ8500G class : DC × 27 (or B27, 1886)

AZ8032G, 35G class : DC × 27 (or B27, 1886)

Select the proper needle in size depending on the thickness and the type of the material.

5.2 Installing needles

WARNING

Before installing the needles, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

(1) Loosen the screw① with an allen wrench. (Fig. 22)
(2) Remove the old needle with a pair of tweezers.
(3) Insert a new needle into the needle clamp② as far as it will go with facing its scarf to the right back. (Figs. 23 and 24)
(4) Tighten the screw① with an allen wrench.

● Accessories include an allen wrench.

NOTE

The tightening torque of the screw ① is 0.6N·m(6kgf·cm).

Japanese standard	8	9	10	11	12	13	14
Metric standard	60	65	70	75	80	85	90

Table 4

Fig. 22

Fig. 23

Fig. 24

5.3 Adjusting thread tension

Adjust the thread tension with the thread tension spring caps ① - ⑥ depending on the type of fabric, the type of thread, seam width, stitch length, and other sewing conditions.

●To tighten the thread tension, turn caps clockwise.
●To loosen the thread tension, turn caps counterclockwise.

Thread\Model	AZ8000G single needle overlock	AZ8020G 2-needle overlock	AZ8500G 2-needle safety stitch	AZ8520G 3-needle safety stitch
Left needle	1	1	1	1
Right needle		2		2
Double chain needle thread			2	3
Upper looper thread	3	3	3	4
Lower looper thread	4	4	4	5
Double chain looper thread			6	6

Table 5

Fig. 25 AZ8020G, AZ8500G

Fig. 26 AZ8520G

Threading

WARNING

Before threading, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

Run the thread correctly as shown in the threading figure attached inside the front cover.

CAUTION

Improper threading can cause thread breakage, skip stitch, and uneven stitch.

Fig. 27 AZ8500G, AZ8520G

5.4 Pressure of presser foot

Loosen the lock nut ① and adjust the pressure of the presser foot with turning the adjusting screw ②.

● To increase the pressure, turn the adjusting screw clockwise.
● To decrease the pressure, turn the adjusting screw counterclockwise.

Keep the pressure as low as possible for stable stitches.

Fig. 28

5.5 Releasing presser foot

WARNING

Before adjusting, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

Rotate the machine pulley and position the needle at the highest point. Release the presser foot to the left while pressing the presser foot release lever ③.

To set the presser foot, slide and push the presser foot against to the right side while pressing the presser foot release lever ③. Then release the lever.

Fig. 29

WARNING

Make sure that the presser arm④ gets into the groove of the presser bar⑤.

If not, it can cause breakage to parts and injuries.

5.6 Opening cover

Front cover ①

To open the front cover①, slide it to the right and tilt toward you.

To close it, raise it. Its spring makes it slide to the left.

Cloth plate②

To open the cloth plate②, shift it to the left while the pushing lever③.

To close it, shift it to the right. Check that it is locked securely.

Fig. 30

5.7 Adjusting differential feed dog

Loosen the lock nut④ and adjust the differential feed lever⑤.

Moving up will make stretching and moving down will make gathering.

Adjust differential feed lever⑤ securely with turning the screw⑥.

● To lower the lever, turn the screw clockwise.
●To raise the lever, turn the screw counterclockwise.

Differential ratio up to 1:0.6 - 1:2 or 1:1 - 1:3 is available by internal adjusting mechanism respectively.

Adjust the graduation, differential ratio, and max. stitch length in Table 6.

Fig. 31

ModelGraduation	AZ8000GAZ8500G class(excluded right models)		AZ8019GAZ8039GAZ8069G		AZ8045GAZ8505G
	Differential ratio	Max. stitch length (mm)	Differential ratio	Max. stitch length (mm)	Differential ratio	Max. stitch length (mm)
S	1:0.7	4	1:0.6	4	1:1	3
1	1:1	4	1:0.9	4	1:1.4	3
2	1:1.6	4	1:1.4	4	1:2.2	3
3	1:2.3	3	1:2	3.5	1:3	2.5

Table 6

5.8 Adjusting stitch length

WARNING

Before adjusting, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

Each graduation on the machine pulley indicates the length(mm) for one stitch.

After sewing, the actual stitch length has difference with the length on graduation. It depends on the application, the type and weight of material to be sewn or the differential ratio.

(1) Rotate the pulley while the pushing push button ①. At the point as far as it will go, again push it securely.
(2) With keeping that, align desired graduation of the pulley with the mark② on the belt cover.
(3) Release the push button①.

●To shorten stitch length, turn the pulley in the direction "S".
● To lengthen it, turn it in the direction “L”.

CAUTION

Check that push button is released completely and the pulley rotates smoothly.

Table 7 shows the adjustable range of stitch length.
Table 8 shows the number of stitches per inch (25.4 mm) and 30 mm converted stitch length.

Illustration of a hand operating a sewing machine with a gear and a belt, showing no text or symbols.

Fig. 32

Line drawing of a hand holding a mechanical component with a dial indicator (no text or symbols)

Fig. 33

Model	Stitch length (mm)
AZ8000G, AZ8500G class (excluded below)	1-4
AZ8016G	1-2
AZ8039G, AZ8045G AZ8069G, AZ5079G AZ8505G	1-3

Table 7

Stitch length (mm)	Number of stitch (per 1 inch) (25.4 mm)	Number of stitch (per 30 mm)
1	25	30
2	12	15
3	8	10
4	6	7.5

Table 8

5.9 SP device and HR device

SP device (needle thread oiling) and HR device (needle point cooling) are equipped as standard to prevent thread breakage and skip stitch when running the machine at high speed or using synthetic thread and/or synthetic fabric.

CAUTION

1. When not using SP device and HR device, remove the felts ③ and ⑤. It may occur irregular condition during sewing.
2. If the silicone oil is sticked to the parts other than SP and HR devices, it can cause the machine trouble. Be sure to wipe it away.

Use dimethyl silicone oil.

Check the oil amount in SP tank①. If not enough, supply the oil into the hole②.

Check the oil amount after opening the oil container plug④ of HR device. If not enough, supply the oil.

Fig. 34 SP device

Fig. 35 HR device

5.10 Cleaning the machine

WARNING

Before cleaning, ALWAYS turn the motor switch OFF and check that the motor has already stopped.

Clean waste thread and dust inside the machine at the end of work everyday.

Clean the slots in the stitch plate and the feed dog area once a week.

CAUTION

Clogged dust can cause breakage to parts and oil leakage.

Cheking of the machine at the sewing factory (by maintenance of technician)

Daily maintenance:

(1) Before operating, remove the machine cover and re-thread correctly without slacking. Check that the thread hanger is right above the soopl seat discs of the thread stands (the thread stands should be fixed securely).
(2) Check the lubricating and silicone oil amount. Supply them if necessary.
(3) Check the order of threading.
(4) Check the bend of needles, damage to tips, and the setting positions respectively.
(5) Check the sharpness of knives.
(6) Check the seam by testing sewing of fabric.

◆ stitch length, differential feeding

◆ adjusting knives and thread tension

Weekly maintenance:

(1) On weekends, clean the machine carefully by removing the presser foot and the stitch plate.
(2) Check the tension of V-belt.
(3) Replenish the lubricating oil.

Line drawing of a sewing machine with hands operating it (no text or symbols present)

Fig. 36

6. Adjustment of sewing machine

WARNING

Before adjusting, ALWAYS turn the motor switch OFF and check that the motor has stopped.

6.1 Needle thread tension for overlock stitch

To set the standard position of needle thread eye-let①, position the center of the screw② between the marks③ and ④.

To set the standard position of the needle thread pull-off⑤, align the portion⑥ with the eye⑦ of the needle thread eyelet(right) when the needle thread pull-off⑤ comes at the extreme front. Loosen the screw⑧ to adjust it.

● To loosen the needle thread tension, move the needle thread eyelet and the needle thread pull-off in the direction "L".

●To tighten the needle thread tension, move them in the direction "T".

Fig. 37

Fig. 38

6.2 Looper thread tension for overlock stitch

The standard setting of each needle thread eyelet:

Upper looper supplementary thread eyelet①

Move it to the extreme left.

Looper thread eyelet②

Move it to the mark③.

Upper looper thread eyelet④

Position the center of the screw with the third line⑤ from the left.

Lower looper thread eyelet⑥

Position the center of the screw with the second line⑦ from the top.

Upper looper thread pull-off⑧

Align the eye of the thread pull-off with the mark⑨ when the lower looper moves to the extreme right.

Lower looper thread pull-off⑩

Tighten it with the screw at the center of the slot.

Thread pull-off ⑪

Align the eye of the thread pull-off with the mark ⑫ when the lower looper moves to the extreme right.

● To tighten the thread tension, move each thread eyelet or thread pull-off in the direction “T”.

● To loosen the thread tension, move them in the direction "L".

6.3 Needle thread tension for double chainstitch

◆To set the standard position of the needle thread eyelet(left) (double chain)③, adjust the needle thread of double chain on a level with the eyelet(left)③ when the needle bar is at the highest point.

Loosen the screw④ to adjust it.

◆To set the standard position of the needle thread eyelet holder (double chain) ①, position the center of the slot in the center of the screw ②.

◆To set the standard position of the needle thread eyelet(right) (double chain) ⑦, align the portion⑥ with the eye⑧ of the eyelet(right)⑦ at the most frontward position of the needle thread pull-off⑤ when the needle thread eyelet holder (double chain) and the needle thread pull-off are at the standard position.

Loosen the screw⑨ to adjust it.

● To loosen the needle thread tension, move the needle thread eyelet and the needle thread pull-off in the direction "L".

●To tighten the needle thread tension, move them in the direction "T".

Fig. 40

Fig. 41

6.4 Looper thread tension for double chainstitch

◆ Align the eye of the double chaining looper thread eyelet③ with the surface② of the double chaining looper thread take-up① when being a level with the straight line A.
Position the thread retaining finger ④ on 1 mm above the eye of the looper thread eyelet ③.
◆To set the standard position of the double chaining looper thread eyelet③, position the center of the slot in the center of the screw⑤.
● To loosen looper the thread tension, move the looper thread eyelet in the direction "L".
●To tighten the looper thread tension, move it in the direction "T".
◆ At the standard timing of the looper thread take-up, the looper thread take-up starts taking up the looper thread when the needle starts lowering from the highest point.

NOTE

Set the thread retaining finger in the center of double looper thread take-ups when tightening the screw of it.

Fig. 42

6.5 Adjusting the width of overedge seam

Before adjusting, set the edge of the upper knife ① 0 - 0.5 mm above the lower knife ②.

To make wide overedge seam:

(1) Loosen the screw③ on the upper knife holder.
(2) Tighten the screw③ securely after moving the holder as desired in the direction "W".
(3) Loosen the screw④ on the lower knife holder.
(4) The lower knife ② touches the upper knife ① closely with its spring.
(5) Tighten the screw④ securely.

Fig. 43

To make narrow overedge seam:

(1) Loosen the screw ④ on the lower knife holder.
(2) Tighten the screw④ slightly after moving the holder as desired in the direction "N".
(3) Loosen the screw③ on the upper knife holder.
(4) Tighten the screw③ with applying the upper knife① to the lower knife②.
(5) Loosen the screw④.
(6) The lower knife ② touches the upper knife ① closely with its spring.
(7) Tighten the screw④ securely.

Fig. 44

NOTE

1. After changing the width of overedge seam, check the sharpness of the blades by setting the thread between the upper and the lower knives with rotating the machine pulley by hand. (See "6.6.4 Sharpness of knives")
2. Use a stitch plate applicable to the width of overedge seam.
   Adjustable range of overedge seam is within ± 0.5 mm based on the value indicated the gauge respectively.
3. Dust clogged at the connecting part of the upper knife holder changes the installing angle of the knives. It will make them cut badly. Be sure to clean the parts by loosening the screw ③.

6.6 Adjusting upper and lower knives

6.6.1 Height of lower knife

Install the edge of the lower knife ① on a level with the top surface of the stitch plate or 0-0.3 mm lower than it.

Loosen the screw② to adjust it.

Fig. 45

6.6.2 Height of upper knife (flat type)

Adjust the engagement between the upper knife ③ and the lower knife ① to 0.5 - 1.0 mm when the upper knife is at the lowest point.

Loosen the screw④ to adjust it.

Fig. 46

6.6.3 Height of upper knife (angled type)

Loosen the screw⑦ and apply the upper knife⑤ to the stopper⑥ fully. It makes the height automatically.

Then tighten the screw⑦ securely.

Fig. 47

6.6.4 Sharpness of knives

After adjusting the knives and the width of overedge seam, check the sharpness of the blades by setting the thread between the upper and the lower knives while rotating the machine pulley by hand.

Fig. 48

6.6.5 Sharpening knives

If the lower knife cuts badly, re-sharpen it. (See Fig. 49)

The upper knife made of super hard alloy is unnecessary to re-sharpen for about one year and normal grinder is not useful for re-sharpening it.

Keep another upper knife for spare.

If needed, contact us directly or the dealer for re-sharpening it.

Fig. 49

6.7 Height of feed dogs

To set the standard position, set the top surfaces of the main and the differential feed dogs parallel to that of the stitch plate when the top surfaces of the feed dogs are raised and on a level with that of the stitch plate.

Adjust the height between the top surface of the stitch plate and the rear side of the main feed dog③ to 0.8 mm when the feed dog is at the highest point.

AZ8000G class (See Table 9) :

Install the auxiliary feed dog⑤ on 0.5 mm lower than the main feed dog③.

AZ8500G class (See Table 9) :

Install the auxiliary feed dog⑤ on a level with the main feed dog③.

Adjust the differential feed dog①, the main feed dog③, and the auxiliary feed dog⑤ with loosening the screws②, ④, and ⑥ respectively.

NOTE

1. Make sure there is no difference of installing height between the main feed dog ③ and the differential feed dog ①. If different height between them, it can cause the unstable feeding and feed scratch mark.
2. For sewing heavy weight knitted fabric or the material having uneven thickness parts, adjust differential feed dog ① and main feed dog ③ on 1.0 mm higher than standard position respectively.

The difference of installing height between the main feed dog and the auxiliary feed dog :

Model	Difference (mm)
AZ8000G class(excluded below)	0.5(lower than the main feed dog)
AZ8016G, AZ8019GAZ8032G, AZ8035GAZ8039G	0
AZ8500G class(excluded below)	0
AZ8500G-53	0.5(lower than the main feed dog)

Fig. 50

Fig. 51 AZ8000G class

Fig. 52 AZ8500G class
Table 9

6.8 Adjusting needles and loopers

Adjust them as follows:

(1) Height of needle
(2) Installing angle of lower looper
(3) Distance between needle and lower looper
(4) Front-and-rear position of lower looper
(5) Distance between needle and upper looper
(6) Front-and-rear position of upper looper
(7) Timing between lower looper and upper looper

6.8.1 Height of needle

(1) Loosen the screws① and remove the logo plate ②. (Fig. 53)
(2) Remove the screw③.
(3) Raise the needle bar at the highest point while rotating the machine pulley.
(4) Loosen the screw④ and adjust the needle bar while moving it up and down.

When the needle bar is at the highest point, adjust the height from the top surface of the stitch plate to the tip of needle to the value "N" in Table 10.

Model		Height of Needle “N” (mm)	Fig.
AZ8000G class single needle	excluded below	10-10.3	54-1
	AZ8016G	8.7-8.9
AZ8020G class 2-needle	excluded below	10-10.3	54-2
	AZ8032G AZ8035G	11.7-12
AZ8500G class		10-10.3	54-3
AZ8520G 3-needle	AZ8520G AZ8525G	10-10.3	54-4

Table 10

NOTE

1. The tightening torque of the screw ④ on the needle bar connecting bracket is 1.5N·m(15kgf·cm).
2. Check the parallel setting of the needles for 2-needle machine and 3-needle machine. (See "6.8.4 Front-and-rear position of lower looper")
3. Apply the liquid packing to the thread of the screw when tightening it.

Fig. 53

AZ8000G class single needle

Fig. 54-1

AZ8020G class 2-needle

Fig. 54-2

AZ8500G class

Fig. 54-3

AZ8520G class

Fig. 54-4

6.8.2 Installing angle of lower looper

To set the standard position, install the angle of 2 - 3^ to the lower looper①.

Adjust rear of the lower looper to 0.5-1.0 mm above the tip of the lower looper with loosening the screw②. (Fig. 55)

6.8.3 Distance between needle and lower looper

Rotate the machine pulley clockwise and move the lower looper ① to the extreme left. Adjust the distance between the tip of the lower lopper and the center of the needle to 3.3-3.8 mm.

Loosen the screw③ on the lower looper holder to adjust it.

6.8.4 Front-and-rear position of lower looper

For single needle overlock stitch on AZ8000G and AZ8500G class:

Adjust the clearance between the tip of the lower looper and the needle to 0-0.05 mm with loosening the screw③.

For 2-needle overlock stitch on AZ8020G and AZ8520G class:

(1) Adjust the clearance between the tip of the lower looper and the left needle to 0-0.05 mm with loosening the screw③.
(2) Adjust the clearance between the right needle and the lower looper to 0 - 0.05 mm when they meet with. Loosen the screw④ and adjust it with turning the needle clamp slightly.
See "6.8.1 Height of needle" on page 28.

NOTE

Tighten the screw ④ after checking the height of needle. When adjusting front-and-rear position of the lower looper, tighten the screw ③ after checking the lower looper's distance.

Fig. 55

Fig. 56

Fig. 57

Fig. 58

Fig. 59

6.8.5 Distance between needle and upper looper

Rotate the machine pulley clockwise and move the upper looper to the extreme left. Adjust the distance between the tip of the upper looper and the center of the needle to the value "U" in Table 11.

(1) Remove the thread eyelet support, the looper thread eyelet, and the looper holder cover.
(2) Loosen the screw② of the upper looper bar crank arm to adjust it.

CAUTION

Apply the liquid packing to the mounting part of the frame when installing the looper holder cover. If not, it can cause oil leakage.

Fig. 60

Model	Distance between needle and upper looper “U”
AZ8000G classAZ8500G class(excluded below)	4.7-5.2
AZ8032GAZ8035G	5-5.5

Table 11

6.8.6 Front-and-rear position of upper looper

The thick portion (around eye) of the upper looper closes to the needle when the upper looper moves from the extreme left to the right while rotating the machine pulley clockwise. (For 2-needle machine, it closes to the right needle.)

Adjust the clearance between the back side of the upper looper① and the needle to 0.05-0.1 mm with loosening the screw③.

Fig. 61

6.8.7 Timing between lower looper and upper looper

Check that the clearance is 0.05-0.1 mm back and forth and 0.05-0.3 mm right and left when the lower looper① meets with the upper looper② while rotating the machine pulley clockwise.

It is correct timing within those clearances.

6.9 Needle and double chaining looper

Timing:

To set the height, insert the double chaining looper③ into the looper holder until it touches the bottom of the holder.

Adjust the distance between the center of the double chaining needle ④ and the tip of the double chaining looper to 2.0-2.2 mm when the double chaining looper ③ is at the extreme left with loosening the screw ⑤.

Tighten the screw⑥ slightly at approximately 6° angle to the looper. Adjust the distance so that the tip of the looper touches the double chain-ing needle④ slightly.

Front-and-rear position:

Adjust the tip of the looper ③ to pass the behind of the needle as closely as possible without touching.

Adjust the needle to pass the behind curved portion of the looper with touching slightly when the looper moves from the right to the left.

Fig. 62

Fig. 63

Fig. 64

Fig. 65

6.10 Needle and needle guards for AZ8000G class

6.10.1 Needle and needle guard(rear)

The needle guard(rear) ① moving with the lower looper is equipped with this machine.

The needle guard(rear) ① holds the needle at behind it and guard the tip of the lower looper When the needle meets with the tip of the lower looper on elevation from the lowest point.

Adjust the clearance between the tip of the lower looper and the needle to 0—0.05 mm with loosening the screw②.

For 2-needle machine, adjust it based on the left needle in the same way as single needle machine.

Fig. 66

6.10.2 Needle and needle guard(front)

Adjust the clearance between the needle guard(front) ③ and the needle to 0.02-0.05 mm with loosening the screw ④.

For 2-needle machine, adjust it based on the left needle in the same way as single needle machine.

Fig. 67

6.11 Needle and needle guards for AZ8500G class

6.11.1 Needle and needle guard(rear)

The needle guard(rear) ① moving with the lower looper is equipped with this machine.

The needle guard(rear) ① holds the needle at behind it and guard the tip of the lower looper When the needle meets with the tip of the lower looper on elevation from the lowest point.

Adjust the clearance between the tip of the lower looper and the needle to 0-0.05 mm with loosening the screw②.

For 3-needle safety stitch machine, adjust it based on the left needle for the overlock seam's needles in the same way as 2-needle overlock machine.

6.11.2 Needle and needle guard(front)

Adjust the clearance between the needle and the needle guard(front)③ to 0.02-0.05 mm with loosening the screw④.

For 3-needle safety stitch machine, adjust it based on the left needle for the overlock seam's needles in the same way as 2-needle overlock machine.

6.11.3 Needle and needle guards for double chainstitch

Needle guard(rear) (double chain stitch):

Adjust the clearance between the needle and the needle guard(rear) ⑤ to 0-0.05 mm at the lowest point of the needle with loosening the screw ⑥.

Needle guard(front) (double chain stitch):

Adjust the clearance between the needle and the needle guard(front)⑦ to 0.1-0.2 mm with loosening the screw⑧.

Fig. 68

Fig. 69

Fig. 70

6.12 Adjusting position of presser foot

Install the bottom surface of the presser foot parallel to the stitch plate from the front. Slanted presser foot can cause feed scratch mark.

To set front-and-rear position, adjust the clearance between needle drop of the presser foot and that of the stitch plate to 0.2 - 0.3 mm as shown in Fig. 71. Loosen the screw① to adjust it.

Fig. 71

7.1 Outline

SC10 is a self-cleaning system that can keep a clean and comfortable environment for operators. It eliminates clogged dust around the lower knife holder and under the stitch plate by cutting material during the sewing. And also makes maintenance easily and prevents troubles caused by the lint.

Fig. 72

7.2 Adjusting ventilating amount

Select the type of setting by changing the position of the air deflector① depending on the sewing speed and sewing condition.

To set the standard position, insert the air deflector① into the guides② and ③. (See Fig. 73) For high speed and less dust during sewing, insert the air deflector① into the guides② and ④. (See Fig. 74)

When not using SC10 device, remove the air deflector①.

Fig. 73

Fig. 74

7.3 Installation

7.3.1 Installing air deflector

(1) Drain the oil from the machine.
(2) Tilt the machine backward.
(3) Loosen two screws④ and remove the wind guide plate②.
(4) Install the air deflector③ into the guides⑤ of the oil reservoir① securely.
(5) Reset the wind guide plate②.
(6) Raise the machine upright and supply the oil.

Fig. 75

Fig. 76

7.3.2 Installing blowing hole screen

(1) Install the blowing hole screen⑥ on the oil reservoir①.
(2) Install the wind guide plate(front) ⑦ on the oil reservoir① while pressing the blowing hole screen⑥ with two screws⑧.

Fig. 77

7.3.3 Installing lint removal pipe

(1) Put two pipe clamps② to the lint removal pipe ①.
(2) Install the lint removal pipe ① and the pipe clamps ② on the machine frame with two screws ③.
(3) Connect the lint removal pipe① to the pipe from the lint collecting device.

CAUTION

Suction is not enough when connecting another device to one lint collecting device for SC10.

When using ventilation, air pressure should be 0.2Mpa (2kgf/cm ^2 ) or more.

Fig. 78

8.1 AZ8000G class

Model		AZ8000G class(excluded right models)	AZ8032G, 8035G
Dimensions		380 (L) ×245 (W) ×310 (H) mm
Weight		26.5 kg
Construction		Dust-proof, Oil-tight and completely sealed
Stitch Type		ISO: 504, 505, 512, 514	ISO: 512, 514
Application		Overlock stitch for knitted or woven farics
Sewing Speed		up to 8000 rpm(see Table 3 on page 10)	up to 7000 rpm
Stitch LengthNumber of stitchesper inch(25.4 mm)per 30 mm		1.0-4.0 mm(see Table 7 on page 17)6.5-257.5-30	1.0-4.0 mm6.5-257.5-30
Needle System		DC×1 Size#8~#14(60~90)	DC×27 Size#8~#14(60~90)
Needle Stroke		23.7 mm	25.7 mm
Presser Foot Lift		(see Table 12)	up to 7.0 mm
Feed Regulation		Push button system
Differential Ratio
		Max. Normal Differential(Gathering)	1:2.3 (see Table 6on page 16)1:2.3
		Max.Reverse Differential(Stretching)	1:0.7
			1:0.7
		Max.reverse differential ratio is available up to 1:0.6 by adjusting the position of the lever pin.
Differential FeedRegulation		Adjustable by moving external lever even during operationAdjustable by Micro adjuster
Knives for Fabric Cutting		Lower Knife: flat type, made of special steelUpper Knife: flat or angled type, made of super hard alloy
Lubricating Oil		YAMATO SF OIL No.28
Capacity of Oil Reservoir		900 cc
Lubrication		Oil is fed forcedly by gear pump
Installation		Fully-submerged type and Semi-submerged type

Model	Presser Foot Lift (mm)
AZ8000G class (excluded below)	6.0
AZ8016G	3.0
AZ8032G, 8035G	7.0
AZ8079G, 8083G	5.0
AZ8093G	5.5

Table 12

8.2 AZ8500G class

Model		AZ8500G class(excluded right models)	AZ8505G	AZ8520G/8525G
Dimensions		380 (L) ×245 (W) ×310 (H) mm
Weight		27 kg
Construction		Dust-proof, Oil-tight and completely sealed
Stitch Type		ISO (504, 401)		ISO (514, 405)
Application		Safety stitch for knitted or woven fabrics
Sewing Speed		up to 7500 rpm	up to7000 rpm	up to 7500 rpm
Stitch LengthNumber of stitchesper inch(25.4 mm)per 30 mm		1.0-4.0 mm6.5-257.5-30	1.0-3.0 mm8-2510-30	1.0-4.0 mm6.5-257.5-30
Needle System		DCx27 (for both sides of overlock stitch and double chainstitch)Size#8~#14(60~90)
Needle Storke		23.7 mm
Presser Foot Lift		up to 6.0 mm	up to 5.5 mm	up to 5.5 mm
Feed Regulation		Push button system
Differential Ratio
		Max. Normal Differential(Gathering)	1:2.3	1:3
		Max.Reverse Differential(Stretching)	1:0.7	1:1
			Max.reverse differential ratio is available up to 1:0.6 by adjusting the position of the lever pin.
Differential FeedRegulation		Adjustable by moving external lever even during operationAdjustable by Micro adjuster
Knives for Fabric Cutting		Lower Knife: flat type, made of special steelUpper Knife: flat or angled type, made of super hard alloy
Lubricating Oil		YAMATO SF OIL No.28
Capacity or Oil Reservoir		900 cc
Lubication		Oil is fed forcedly by gear pump
Installation		Fully-submerged type and Semi-submerged type

1jamato

ヤマトミシン製造株式会社

YAMATO SEWING MACHINE MFG. CO., LTD.

4-4-12, NISHITENMA, KITA-KU, OSAKA, JAPAN

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