Performing basic maintenance - operate machine and assess its performance

WEB SCRIPT Garments
Sector: Dressmaking NCII
Qualification: Perform Basic Maintenance
Unit of Competency: Performing Basic Maintenance
Module Title: Operate Machine and Assess its Performance
Learning Outcomes: Christian Domingo Dacoron
Developer/s:

TITLE Performing Basic Maintenance
OBJECTIVES
Upon completion of this module the students/trainees will be able to:
INTRODUCTION o Operate machine and assess its performance
o Clean and lubricate machine
o Check machine operation

This module covers the knowledge, skills and attitudes required in performing
minor maintenance of the machines used by dressmaker.

LESSON 1 Operate Machine and Assess its Performance

TOPIC 1: Sewing SEWING MACHINE OPERATION
Machine Operation
Sewing machines come with a vast variance in options but the basic operation of
a sewing machine is the same from machine to machine. Once you know the
very basics of operating a sewing machine, you'll want to refer to your machine's
manual so you can use every possible option that your sewing machine offers.

1. Sewing Machine Manual
If you are not the first owner of your sewing
machine, you may not have the manual. It's a
good idea to try to obtain a sewing machine
manual for your sewing machine. The manual
is not going to just tell you how to operate the
machine. It will also teach you how to care for
your specific machine and uncover tips and
tricks you might not learn anywhere else.

2. Sewing Machine Parts
A sewing machine manual can seem like it's

written in a foreign language if you don't know the
different parts of the machine. Newer sewing machines
and older sewing machines all have the same basic
parts—the difference is the newer machine's parts are
less exposed. The pictures of sewing machine parts
you'll find on the line may be depicting an older machine,
just so you can see the actual parts that are hidden on

newer sewing machines. See if you can memorize the basic parts, it will definitely
be helpful as you decipher patterns and troubleshoot sewing machine problems.

3. Speed Control
The foot pedal of a sewing machine is

essentially equal to the gas pedal on your car. The
more you press down, the faster the sewing machine
is going to sew. Most machines can go quite fast. To
get a good feel for the machine's speed, try sewing
barefoot. To get started, keep your heel on the floor
and the ball of your foot on the foot pedal. Try using
only your big toe to press down the foot pedal if you
find yourself going faster than you can control.
Practice learning speed control without the machine
being threaded. Once you can control the speed of the machine, then thread the
sewing machine and practice some more.

4. Sewing Machine Needles
Different fabric requires different sewing

machine needles. The most common telltale that you
need to change the needle is skipped stitches. The
weight and type of fabric all come into play in
choosing the correct sewing machine needle for the
type of fabric you are sewing. There are also special
needles to fill special needs; learn about all of your
sewing machine needle options to eliminate simple-
to-solve problems.

5. Use a guide
Watching the needle as you sew can lead to

some wavy stitching. The best practice is to set a
guide and watch the fabric lining up with the guide as
you sew to obtain straight seams with even seam
allowances. The guide can be on the sewing machine
bed or on the presser foot.
You may also want to experiment with needle
position to obtain the results you want. Remember,
you are in the driver's seat and you decide where the machine is going to stitch
the fabric.

6. Familiarize with Feed Dogs
The feed dog is responsible for taking the

fabric under the needle and feeding it through the
machine. The feed dog works in conjunction with
your presser foot to feed the fabric as it is being
sewn. Your responsibility is to simply guide the fabric
between the feed dog and presser foot.
When you force-feed the machine or tug fabric
through the machine, you can bend the sewing

machine needle and create all kinds of problems. Let the machine do the work
and just guide the fabric at a steady pace.

7. Threading the Sewing Machine
Your sewing machine manual is the best place

to learn how to thread your sewing machine but if you
want to get started and don't have your machine's
manual, the basics of threading a sewing machine
may get you started.
When threading a sewing machine, be sure to thread
them with the presser foot up. When the presser foot
is in the upward position, the tension is released which
allows the thread to seat itself properly. You can test
the difference by tugging the thread at the needle with the presser foot up and
with the presser foot down—the thread will pull smoothly if seated properly.

8. Quality Thread
Grabbing a spool of the thread for a dollar may

seem like a great way to save money, but you may run
into consequences if the thread is lacking in quality.
Thread also ages, so if your machine is acting up and
you are trying to sew with your grandmother's wooden
spool of thread, try a new high-quality thread and see
if it makes a difference.

SETTING OF SEWING MACHINE

Perfect machine stitching is easy to achieve if you set the machine properly. This
involves threading the upper and lower parts of the sewing machine. The
beginner in dressmaking must learn how to thread the head of the sewing
machine as one of the first steps in becoming a competent operator
THREADING THE MACHINE

Each part of the threading mechanism on the head of a sewing
machine has a definite purpose in guiding the thread from the spool to the needle.
The thread must pass through the various guides in a given order so that the
machine will sew properly the formed stitches.

TIPS AND CAUTIONS WHEN THREADING A SEWING MACHINE:

Only use the type bobbins that come with your machine or that have the same
part number. Others will not work and may damage your machine.
Make sure your bobbin has been wound correctly. The thread should be even. It
should not seem loose on the bobbin. Loose thread will cause tension problems
and may cause needles to break.
Be sure to turn off the power to your machine while threading it. An accidental
step on a pedal could cause a serious injury!

TOPIC 2 : Classification CLASSIFICATIONS OF SEWING MACHINE TROUBLES
of sewing machine
troubles If the sewing machine in your laboratory are kept in good condition and
are carefully adjusted and properly threaded, not too many things can go wrong.
But there are certain difficulties that occur during an operation so often, so you

should know these minor and common problems their causes and remedies.
There are two classifications of sewing machine troubles, namely:

1.Minor sewing machine trouble
This refers to problems that arise involving incorrectly attached accessories or
supplies, unadjusted tensions, or that requires a little dusting or oiling.

2. Major sewing machine trouble
This involves replacing or removing damage spare parts that made the sewing
machine not totally functioning.

Machine Causes Remedies
Troubles
1. Machine • Insufficient oil • Oil the sewing
• Loose screw machine
runs • Thread or dust clogged
noisily • Tighten loose
in the shuttle race screw
2. Machine
rotates • Too tight belt • Clean the
heavily • Insufficient oil shuttle race
• Bearings or shuttle race before oiling
3. Needle
thread is clogged with dust or • Change belt if
breaks thread already old

• Improper threading • Oil the arm shaft
• Tight tension • Clean the
• Thread too coarse
• Needle blunt set shuttle race and
bearing, then oil
incorrectly • Check the
• Presser foot not threading,
change the
properly adjusted texture of thread
• Poor quality thread and attach the
• Seam maybe too thick needle properly
to the needle
or heavy bar
• Bobbin case turns • Use correct
• Fabric is pulled forcibly presser foot,
• Needle may be bent check if presser
• Size of needle foot is secured
• Tension and properly
fastened
• If seam is too
heavy, change
needle to
correct size
• Check the
position of the
bobbin case,
reset the shuttle
race assembly
• Change the
bent needle
• To avoid the
needle bending,
pull the upper
and lower

4. Stitches • Bent needle, dull threads towards
skip needle or wrongly the rear of the
attached needle presser foot
5. Stitches after stitching
loop • Unmatched size of and cut the
needle or thread to the threads
texture of fabric • Don’t force the
fabric, just guide
• No enough pressure on it
the presser foot • Change the size
of the needle
• Threading maybe • Adjust the
incorrect tension
• Change the
• Dull needle needle or
• Improper threading correct
• Unbalance tension of positioning
• Change needle
the upper and lower size and thread
threads • Increase
• Defective thread take- pressure on the
up lever presser foot
• Check the
threading
• Use blunt
needle
• Check the
threading;
-if loops appear
under the fabric,
check the upper
threading;
adjust the upper
tension
regulator;

-if the loops
appear on top of
the fabric check
the lower
threading; the
thread may be
inserted in the
tension groove
of the bobbin;

-check also the
latch spring of
the bobbin case.
• Balance the
tension of both
threads
• Change the
thread take up
lever spring

6. Upper • Improper threading • Correct
thread • Improper attached threading
breaks
needle • Attached the
7. Lower • Bent or dull needle needle correctly
or under • Tight upper needle
thread • Poor quality thread • Change to blunt
breaks • Unmatched needle needle

8. Seams • Improper winding of the • Reset the upper
pucker thread in the bobbin tension
regulator
• Bent or dull needle
• Poor quality thread • Use good
• Incorrectly set feed dog quality thread
• Bobbin does not freely and thread size
or texture
turn
• Too tight bobbin case • Winding the
thread in the
spring bobbin uniformly

• Too long stitch length • Change the
for the fabric needle

• Tension is too tight • Use good
• Size of needle and quality thread

thread do not match • Lower the feed
• Too high feed dog dog if the fabric
is thin; raise the
adjustment feed dog if the
• Too heavy pressure on fabric is thick

the presser foot • Check if bobbin
is clogged with
dirt or thread

• Loosen the
adjusting screw
of the bobbin
case or
adjusting the
tension of the
upper thread

• Adjust stitch
regulator to
correct length

• Adjust the upper
and lower
tension
regulator

• Use appropriate
size of needle
and thread

• Adjust the
height of the
feed dog
depending on
the thickness or
thinness of the
fabric

• Lessen
pressure on the
presser foot

9. Fabric • Feed dog not in proper • Adjust the feed
does sewing position dog to proper
not sewing position
move • Stitch regulator not set
on zero • Adjust stitch
regulator to
• Too tight pressure on desired stitch
presser foot length

10. Fabric • Needle may be too big • Add pressure to
jams in • Throat plate presser foot by
machine adjusting the
pressure
regulator screw

• Change the size
of needle

• Needle round
hole plate

STANDARDS FOR SEWING MACHINE OPERATIONS

Observe while using / running sewing machine and list the things that you have
noticed. By following correct procedures, you will make your work easier, more
interesting and challenging. Here are some pointers that you have to follow in the
manipulation of your sewing machine:

1. Start with the right tools and supplies. Have your needle, thread, screw driver,
pins and scissors ready for use. With tools at hand, you can start working
continuously on your machine.

2. Always maintain good working posture. Sit on your back slightly leaning
forward. It can prevent body pains after working on your machine.

3. Thread the sewing machine correctly. You can follow the guide book if you
have. This will save your time to get a correct threading. Refer to someone to
check if you have threaded it properly.

4. Be sure that the needle is properly set according to the directions for specific
models. A properly attached needle will make your work without any trouble.

5. Set the stitch regulator according to project specifications and test the stitches
for possible adjustments.

6. Check tension dials and adjust according to project requirement of the
stitches. A correct adjustment on the tension dials will make perfectly sewn
garment.

7. Turn power off (for motorized/electric machines) when the sewing machine is
not in use. This will save electricity and avoid possible minor accidents.

8. Keep sewing tools. Dust the sewing machine then put a little amount of
machine oil in slots. This will make the sewing machine available for the next
user

TOPIC 3 Note: The control of the sewing machine lies on your feet not in your hand so
learn to start and stop the sewing machine instantly at a given point using this
control. Lower the presser foot while sewing but be sure to insert a piece of paper
or fabric swatches so that the feed dog will not be worn out.

CHARACTERISTICS OF GOOD STITCHES

1. The length of stitch is proportioned to the texture of the fabric.
2. The stitches are the same in length.
3. The stitches appear the same on both right and wrong sides of the fabric.
4. The stitching follows the intended line smoothly and accurately.
5. There are no skipped or broken gaps in stitching.
6. When retraced, it appears as one line of stitching.
7. The stitching has no tangles.

HOW TO MAKE ADJUSTMENT ON THE MACHINE
There are two tension adjustments on the sewing machine the upper and

the lower. The upper tension controls the thread from the needle, while the lower
tension controls the thread from the bobbin case. These tensions must be
adjusted to suit various fabrics. If the tensions on both threads are properly
adjusted, the threads will lock at the center of the material and form a correct
stitch.

The size of the stitches varies with the type of work being sewed. Thin
materials require a short stitch, a light thread, a fine needle, and a tight tension.
Heavier materials require a longer stitch, a coarser thread, a larger needle, and
less tension.

Sewing machine needles become dull through hard usage and also
through ordinary wear; sometimes, they become bent by improper use. The
condition of the needle should be checked when sewing difficulties occur. A
defective needle should be replaced by a new needle of proper size. A dull needle
will show a flat shiny spot at the very tip when rotated between the fingers. The
straight of a needle can be tested by rolling the larger end on a flat surface; bent
needles will wobble and straight needles will roll true.

A. HOW TO ADJUST TENSION ON THE NEEDLE THREAD

The stitch tension control determines the amount of tension on the thread as they
pass through the machine.

1. Correcting a Loose Top Stitch
When the needle thread tension is too tight, the thread will lie straight along the
upper surface.

• Lower the presser foot
• Turn the small thumb nut at the front of the tension discs to the left

(counter clockwise) to decrease the tension.

Image by Juki Club https://www.jukiclub.com/top-tension-tips/

2. Correcting a Loose Bottom Stitch
When the needle tension is too loose, the thread will lie along the underside of
the material.

• Lower the presser foot
• Check to make sure that the thread is between the tension discs.
• Turn the small thumb nut at the front of the tension disc (clockwise) to

increase the tension.
• Check the stitch on pieces of scrap material.

B. HOW TO ADJUST TENSION ON BOBBIN THREAD

1. Checking Bobbin Case

• Remove the bobbin from the bobbin case.
• Clean the inside of the bobbin case.

Image by Lindee G Embroidery https://lindeegembroidery.com/

Remove all particles of lint and dust with a small point stick.
Note: If the tension spring is bent away from the bobbin case, or if the
ends of the spring near the delivery eye are damaged, they should be
replaced. Consult your teacher if defective parts are discovered.

2. Adjusting Tension Spring on Bobbin Case
The tension on the bobbin thread is controlled by adjusting

the tension spring on the outside of the bobbin case. It is seldom
necessary to change this adjustment once the tension has been properly
set. The operator will usually be able to correct the stitch by varying the
tension on the needle thread.

Image by Threads https://www.threadsmagazine.com/

A. Correcting a loose bobbin thread
If the tension on the bobbin thread is too loose, the needle

thread will lie straight along the upper surface of the material.

• Tighten the tension
• Turn the regulating screw in the tension spring to the right.
• Test the tension. Thread the bobbin case. Hold the end of the

thread and allow the case to hang freely.
• Check stitch on pieces of scrap material

B. Correcting a Tight Bobbin Thread
If the tension on the bobbin thread will lie straight along

the underside of the material.

• Loosen the tension. Turn the regulating Screw in the tension
spring slightly to the left.

• Thread the bobbin case and test the tension.
• Check stitches on pieces of scrap material.

HOW TO REGULATE THE LENGTH OF THE STITCH

The length of the stitch is regulated by the stitch regulator on the front side of
the head.

• Move the stitch regulator downward to lengthen stitch
• Move the stitch regulator upward to shorten stitch.
• Check the length of stitch on pieces of scrap material.

Note: For normal stitching, set the regulator at 10 to 12 stitches per inch, or at
the number 3 for metric scale machines.

Image by Sew4Home https://sew4home.com/

Image by Needle Bar http://needlebar.org/

HOW TO REGULATE THE PRESSURE ON THE MATERIAL
The pressure on the material is regulated by adjusting screw on the top of the
machine.

• Turn the adjusting screw to the right to increase the pressure.
• Turn the adjusting screw to the left to decrease the pressure.
• Check the pressure by stitching on pieces of scrap material of the same

weight.
The pressure of the presser foot can be adjusted by turning the pressure
adjustment screw at the top left of the machine. Since the machine has already
been adjusted to a pressure suitable for lightweight and medium fabrics, no
further adjustment is necessary except when sewing on very heavy or very light
materials. Usually, when sewing on very light materials, the presser foot pressure
should be loosened. When sewing very heavy materials, the presser foot
pressure should be tightened.

1. Pressure Adjustment Screw
2. Less Pressure
3. More Pressure
4. Pressure Adjustment Screw

5. Standard height for medium material

LESSON 2 Image by Brother 1034d Serger http://brother1034dserger.org/

TOPIC 1: Care of Note: A pressure that is too heavy will cause the machine to run hard and will
Sewing Machine leave the print of the feed on fine materials.

Clean and Lubricate Machine
Care of Sewing Machine

How to Clean and Oil Your Sewing Machine

Cleaning and oiling your sewing machine is basic maintenance
that bits of lint, thread, dust and even fabric can get stuck in your machine.
These make work harder and can even jam your sewing machine. Clean your
machine to fix these help the machine to last longer and perform more
smoothly. If you sew regularly, problems and use sewing machine oil to help the
moving parts function smoothly. You should clean and oil your machine after
finishing any large project as well as any time you suspect it is having a
problem.

INSTRUCTIONS:

1. Prepare the needed tools and supplies in cleaning the sewing machine.

2. Remove the needle if there is any. This will prevent the cleaner from pricking
fingers during the cleaning process.

Face Plate (presser bar, needle bar, thread take up lever, lifter).

• Unscrew face plate and keep it in the drawer while cleaning.
• Brush dust away then put a little amount of oil while rotating the balance

wheel to inner parts can be accessed.
• Put back the Face Plate in place

Cleaning and oiling your sewing machine is basic maintenance that can help
the machine to last longer and perform more smoothly. If you sew regularly, bits

of lint, thread, dust and even fabric can get stuck in your machine. These make
work harder and can even jam your sewing machine. Clean your machine to fix
these problems and use sewing machine oil to help the moving parts function
smoothly. You should clean and oil your machine after finishing any large
project as well as any time you suspect it is having a problem.

UPPER TENSION (DISC SPRING AND DIAL)

• Remove outer bolt, tension dial, discs and disc spring.
• Lay each part in your front table following its disassembling for easier

assembling.
• Brush dust and wipe with absorbent cloth with oil.
• Assemble by following the laid parts in your table.

LOWER MECHANISM (ROTARY OSCILLATING HOOK)

• Remove bobbin case.
• Fasten sides of oscillating hook.
• Remove dust with lint brush.
• Put a little amount of machine oil on moving parts.
• Return spare parts in place.

OTHER MINOR PARTS

• Remove entangled threads between head and balance wheel.
• Brush accumulated dust in the treadle joints connecting the band wheel.
• Clean gummy dust on the band wheel.
• After all parts were dusted, lubricate all joints and oil slots with good

quality oil.
• Wipe off all surplus oil then put a piece of absorbent cloth under the

presser foot for dripping oil.

SUB-TOPIC: What is Note: When the machine has thoroughly cleaned and oiled, run it slowly for
Sewing Machine Oil? several minutes to allow the oil to work on its moving parts. Place a scrap of
fabric under the presser foot and lower the needle to absorb excess oil.

What is Sewing Machine Oil?
An essential part of sewing machine maintenance, learn all you need to know
about sewing machine oil and how to use it.

Sewing machine oil is a lubricant specifically made for sewing machine parts,
recommended to be used approximately every 8 hours of sewing. The use of
sewing machine oil lessens the friction between the machine's parts, keeping
them from grinding on one another and wearing down.

Types of Sewing Machine Oil
there are three types of sewing machine oil:

1. Mineral oil
This type of oil is made from petrochemicals, or substances produced from
petroleum. This type of oil is odorless, watery white, and the most effective. Most
sewing machine oils are made from petrochemicals.
2. Synthetic oil

SUB-TOPIC: OHS in Synthetic oil is an artificial alternative to mineral oils and is generally safe to use
sewing machine on plastic, rubber, and painted surfaces. This type of sewing machine oil is
maintenance generally more expensive than mineral oil.
3. Natural oil
Natural oils are natural substitutes to sewing machine oils and can be made from
jojoba, silicone, and ester oils. Though natural, natural oils often don't work as
effectively as mineral or synthetic oils and may gum up your machine if not mixed
properly.

Note: Never use oils that are not specifically made for your sewing machine, like
motor oil or cooking oil. These substances may gum up your machine or cause
parts to malfunction.

How to Use Sewing Machine Oil
In a SewingMachinesView.com article, "Best Sewing Machine Oil," Barbara
Harris states that it is recommended to oil your machine after approximately 8
hours of sewing in order to effectively prolong its life. Every sewing machine
should have detailed instructions on when, where, and how to oil your machine.

However, here are a few tips on how to use sewing machine oil:

1. Never oil your sewing machine while it is plugged in.

2. You may have to disassemble parts of your sewing machine in order to
reach individual pieces.

3. So that you don't trap lint or dust in your machine, you should always
brush your machine's parts with a small brush and/or air compressor before
applying the sewing machine oil.

4. If you ever apply too much oil, wipe away excess with a towel or rag. This
way, extra oil does not get on anything it shouldn't, like wires or fabric.
5. Don't use sewing machine oil that has gone bad. You can tell if it has gone
bad if the usual clear-white, odorless substance becomes thick, yellowish, and/or
smelly.
OCCUPATIONAL HEALTH AND SAFETY PROCEDURE IN SEWING
MACHINE MAINTENANCE

Cleaning and lubricating a sewing machine is quite a messy task. Personal care
should be observed during this activity. The following health and safety
precautions should be practiced at the shop or at home.

1. Wear personal protective equipment. This prevents your clothing from being
tarnished by oil and dirt. Be sure to wear gloves to avoid accumulation of oil and
dirt in your nails and palms. (Wearing of protective eye glasses is optional).
2. Remove the upper belt or turn power off before oiling the sewing machine.
3. When a chemical or small spare part get into your eyes, call the attention
of your teacher at once.
4. Do not remove any safety device from any machine.
5. Be sure that all screws are well-lightened before starting the machine.
6. Make sure that no screws or tools are left on the floor to avoid slipping.
7. Wipe dry spilled oils on the floor to avoid accidents.
8. Assign colored tags for a newly maintained sewing machine
9. Provide a small bin for your garbage when performing this job.
10. Have a separate cabinet or storage for tools and supplies for sewing
machine maintenance.

TOPIC 2 11. Always refer to the sewing machine service manual for accurate application
of procedure.

Note: A sewing machine is an equipment that needs care and cleaning. Keep
it dusted and lubricated at least once a week or more often if the machine is in
constant use.

SEWING MACHNE MAINTENANCE CHECKLIST
Preventive Maintenance

o Check to see if the machines are being kept clean
o Machines should be blown off every day to remove lint and
trash
o On lockstitch machines, the hook should be blown off regularly
during the day to prevent lint or dirt building up in oil ports in
the race of the hook

o Check to see that the machine is being lubricated regularly
o Oil levels should be checked daily and added if necessary
o Random check the oil level in the machines
o A high quality white machine oil should be used that will not
stain
o Check availability of proper machine oil in the factory
o Check to make sure the oil is not contaminated
o Check to see that oil reservoir pump filters are cleaned
regularly

o If compressed air is used, make sure the air system is regulated
properly and has humidity dryers, filters and lubricator in the air lines

o Check for rusted areas due to excessive moisture in production area
o Check machines for wear on critical moving parts

o Check for shake in needle bar due to worn needle bar bushings
o Check for excessive movement in stitch forming devices, etc.
o Check the condition of critical screws
o Check for missing screws
o Check for defective screws that are difficult to lighten properly
o Check condition of mechanics tools to see that they are being
maintained properly

** Every sewing machine has three basic system used to form and set the stitch. These
three systems incude: 1. Stitch forming system; 2. Thread handling system; and 3. Fed
system. We will look at each of these systems independently.

Stitch Forming System
o The sewing machine needle should be inspected regularly during the
day and replaced if there are signs of wear or damage
o The correct type and size of needle should be used
o Wovens – sharp pointed needles
o On the light weight fabrics where structural
jamming can cause seam puckering, the finest
needle size should be used with a long-point
o Knits – ball pointed needles of the finest size should be used
o The correct needle size – thread size relationship should be maintained
o Lockstitch machines
o Check the hook for sharp surfaces and burns on the hook
point

o Check for other sharp surfaces on other contact surfaces
o Check for excessive wear in the raceway which will allow

excessive movement in the basket
o Chainstitch and Overedge machines

o Check the looper points for sharp surfaces or burns
o Observe excessive wear of looper
o Check to make sure loopers are shaped properly according to

original factory condition
** Observe method of removal of entangled thread on loopers. Sharp objects that can
nick or burr the loopers should not be used.

Thread Handling System
o Check to make sure thread is being stored properly
o Cones should store properly to ensure that they are not
contaminated with dirt, excessive lint, etc.
o Check to make sure wind on part cones does not affect take-
off the cone
o Check to make sure the correct thread type and sizes are being used
o If thread vendor is specified, check order book and inventory
to make sure the proper thread is being used
o Thread stands are in proper condition and the top eyelets are
oriented properly
o Optimum distance between the top of cone and top eyelets
(should be no more than one cone higher than cone size
being used)
o Thread stand eyelets are smooth and not grooved or
damaged
o Cone is held in a vertical stationary position
o Machine eyelets and guides are smooth and not grooved, rusted or
damaged
o Machine thread tensions are as light as possible but still give balanced
stitches
o Observe how much of the tension post is exposed beyond
the tension nut
o Generally, the more of the tension post that is visible,
the more tension that is being applied to the sewing
thread
o Observe the condition of the tension disc, take-up spring, etc.
o Check the bottom tension to make sure it is as loose as possible and
still give a balance stitch

o Lockstitch machines
o Bobbin winder in good condition and making correct win on
bobbins
o Condition of bobbins and bobbin tension
o Look for nicks on edge of bobbin indicating
incorrect needle height
o Look for damaged or bent bobbins
o Check bobbin tension (minimum tension recommended)
o Bobbin tension of bobbin case
o Bobbin tension with bobbin case laying on a flat
surface

o Bobbin tension after bobbin thread has been pulled
up through the hole in the needle plate

o Needle thread
o Machines are properly threaded
o Needle thread tension is as light as possible but still give a

balanced stitch
o Take-up spring in proper positioned and working properly
o Proper thread size / needle size relationship is being maintained
o Proper needle thread size / bobbin thread size is being used

Feed System Needle plates are in good condition
o o Make sure the needle hole size / needle size relationship is

o correct
o o Generally, the needle hole size should be twice the
o
o diameter of the needle being used
o Check to make sure the needle hole in the needle
o
plate is not damaged
o Look for needle damage and sharp edges
o Check to see if the needle plate is flat and not bent

down at the needle hole

Chainstitch needle plates
o Observe to see that the length f the needle hole slot is

greater than the stitch length
o Observe to see that the underside of the needle hole is

sharped correctly to aid in forming a proper triangle

Feed dogs are in good condition and correct for the application
o Check to make sure the feed is not broken or damaged
o Observe the teeth per inch on the feed dog
o Generally, the following should be found: light

weight sewing – 20-24 teeth per inch; medium

weight sewing – 14-18 teeth per inch; and heavy

sewing – 10-12 teeth per inch

Over edge needle plates
o Check for needle damage or burns on the needle hole and

stitch tongue
o Make sure the trimming knives are adjusted to the width of

the needle plate stitch tongue

Presser foot
o Correct foot is being used for application
o Make sure the needle hole size / needle size relation is

correct and the needle has sufficient clearance
o Check to make sure the needle hole is not damaged
o Check for proper pressure both in front and in back of the

needle
o With the foot flat on the needle plate, you should not be

able to insert a thin piece of paper between the foot and

the needle plate from the front or back side of the needle
o Check presser foot for excessive wear causing side-to-side

play

The pressure on the presser foot should not be as light as possible

and give a uniform stitch length

o Check to make sure the correct stitch length is being used

Other System Material trimming systems
o o Check to see that the cutting knives are sharp and are
trimming properly. This can be checked by placing a single
o end of thread between the knives and observing if the
o thread is cut by the knives

Thread trimming system
o Check to see that the chain cutters are cutting the chain to
the proper length that minimizes trim and inspect

Folders and guides
o Observe to see that the correct capacity folder is being used
for the fabric being sewn
o Check for additional folds caused by excessive
folder capacity
o Check for excessive stretching of the fabric causing
additional seam puckering

Stitch and Seam Quality
o Lockstitch seams
o Check to see that the stitch looks the same on both the top

and bottom of the seam
o If back tacking is required, make sure the correct number of

stitches are used in the back tack
o Make sure the proper SPI are being used
o Make sure the correct seam allowance (margin) is being maintained
o Chainstitch seams

o Make sure the stitch is balance properly
o Check for excessive seam grinning
o Looper thread should roll over
o Overedge seams
o On overedge seams, check for proper stitch balance
o Check for excessive seam grinning
o Check for proper seam extensibility or stitch elongation
o Check to make sure that the purl is on edge of the seam
o Check to make sure that the knives are trimming the fabric

cleanly
o Check to make sure the correct seam allowance (margin) is

being maintained
o Observe operator handling for excessive trim
o If latch-tacking, make sure the chain is sewn into the seam

properly
o Skipped stitches

o Check areas where frequent skips have been observed
o Observe where one seam crosses another seam
o Check if skip occurs on thickness or after thickness

TASK SHEET: Clean and Lubricate Sewing Machine

STEPS/PROCEDURE:
• Prepare the needed tools and cleaning materials.

• Remove the needle if there is any. This will prevent the cleaner from
pricking fingers during the cleaning process.

UPPER TENSION (DISC SPRING AND DIAL)

• Remove outer bolt, tension dial, discs and disc spring.
• Lay each part in your front table following its disassembling for easier

assembling.
• Brush dust and wipe with absorbent cloth with oil.
• Assemble by following the laid parts in your table.

LOWER MECHANISM (ROTARY OSCILLATING HOOK)

• Remove bobbin case.
• Fasten sides of oscillating hook.
• Remove dust with lint brush.
• Put a little amount of machine oil on moving parts.
• Return spare parts in place.

OTHER MINOR PARTS

LESSON 3 • Remove entangled threads between head and balance wheel.
• Brush accumulated dust in the treadle joints connecting the band wheel.
TOPIC 1: Sewing Machine • Clean gummy dust on the band wheel.
Safety: 10 Safety Tips to • After all parts were dusted, lubricate all joints and oil slots with good
avoid Injury quality oil.
• Wipe off all surplus oil then put a piece of absorbent cloth under the
presser foot for dripping oil.

Check Machine Operation

Sewing Machine Safety: 10 Safety Tips to avoid Injury
1. Learn the distance

The most obvious risk when you are using a sewing machine is the moving needle that
you are feeding your fabric through. The best thing you can do is the easiest step: keep
your fingers a safe distance away from the needle. Generally speaking, this is
considered about an inch away from the needle at all times.

2. Keep your hair out of the way
If you have a long hair, it will be a nightmare if you aren’t careful and allow it to get
caught up in the workings of your sewing machine. Unfortunately, when you are
working, leaning over your machines to get closer look, your hair can be a danger if
you aren’t careful. Luckily, though, you can easily avoid any mishaps by just pulling
your hair back with a hair tie while you work.

3. Concentrate
When you are working on your sewing machine, to stay safe you will need to focus on
what you are doing. If you aren’t it’s easy for an accident to happen such a simple sli of
the hand. To avoid this, only use a sewing machine when you are able to focus on what
you are doing.
This also means that if you are under the influence of anything that could affect our
focus – such as medication- you might want to avoid the sewing machine until you can
focus properly.

4. Make sure your pins and needles are intact
When you are setting your sewing machine up, you are going to want to make sure
that any pins and needles that you use are completely whole and undamaged. Not
only could a broken needle lead to damage to your machine or the destruction of your
fabric, it could potentially become a dangerous projectile.

5. Don’t sew over pins
In the same strain as our last tip, you are going to want to make sure that you take ins
out of your fabric as you go. Sewing over pins can cause them to break and potentially
fly out at you. In addition to the potential danger, though, a breaking pin could also
damage your machine or fabric.

6. Use the right machine
If you are planning on sewing throw strong or thick fabrics, you might want to consider
using an industrial sewing machine rather than a standard household machine.
Otherwise, you risk breaking your machine which can lead to dangerous situations.

7. Be mindful of electricity
When you are using your sewing machine, you are adding electricity to the mix. So,
you need to be careful of the damage electricity can do. You can keep yourself safe by
taking simple steps such as not overloading outfits and not using cords that are frayed,
cut, or otherwise damaged with your machine.

8. Listen to your machine
A theme that you might have noticed as we have gone through these tips is that a
broken machine can spell danger. As such, you should make sure to listen for any
problems your machine could have. If you hear any rattling or grinding, for example,
you should consider taking your machine to get checked out.

9. Service your machine
A sewing machine, much like a car, needs regular maintenance. About every two years,
you should take your machine to get serviced by a professional so you can avoid the
mishaps that a broken machine can cause.

10. Turn it off when not in use
Don’t let your sewing machine sit on idly even if you’re only stepping away from a
project for a minute to avoid any accidents. You should especially make sure the
machine is off and unplugged before you start making any repairs-the last thing you
want is to have your hand in the machine and for it to cut on.