Lock stitch sewing machine

20 minute read

introduction

The lockstitch machine, also known as an
oscillating hook machine, has a rich history dating
back to the late 19th century.
In 1874, Allen B. Wilson invented the first
lockstitch machine, revolutionizing the sewing
industry

Since then, the lockstitch machine has
undergone significant improvements, becoming an
essential tool in various industries.
A lockstitch machine is a type of sewing
machine that uses a rotating hook to create a
lockstitch, a specific type of stitch that loops one
thread around another to secure fabric together.

The lockstitch is characterized by its
simplicity, strength, and flexibility, making it an
ideal stitch for a wide range of applications.

This process creates a strong, flexible, and
reliable lockstitch, making the lockstitch machine an
essential tool.

Processes involved in using a lockstitch machine

Threading: Thread the machine with the
desired thread, following the manufacturer’s
guidelines.
Bobbin Winding: Wind the bobbin with the
same thread, ensuring proper tension.
Fabric Preparation: Prepare the fabric by
cutting, marking, and aligning it as needed.
Machine Setup: Adjust the machine settings,
such as stitch length and tension, according to
the fabric type and desired stitch.
Fabric Feedin: Feed the fabric into the
machine, guiding it smoothly and evenly.
Sewing: Begin sewing, using the handwheel or
foot pedal to control the machine.
Stitch Formation: The machine creates a
lockstitch, looping the thread around the
previous stitch.
Thread Take-Up: The machine pulls the thread
tight, securing the stitch.
Fabric Advancement: The feed dog pulls the
fabric forward, allowing continuous sewing.
Backstitching: Reinforce the beginning and
end of the seam with backstitches.
Thread Trimming: Trim excess thread with
scissors or a thread trimmer.
Fabric Inspection: Inspect the sewn fabric
for quality and accuracy.
Additionally, some lockstitch
machines may have specialized processes, such as:
Automatic Thread Cutter: Cuts the thread at the
end of the seam.
Automatic Backstitching: Reinforces the beginning
and end of the seam with backstitches.
Stitch Regulation : Adjusts the stitch length and
tension automatically.

PARTS OF LOCK STITCH SEWING MACHINE

Light/Medium Selector
found on some lockstitch machines that allows the
user to adjust the machine’s settings for sewing
different weights of fabric.
The Light/Medium Selector typically has two
settings:

Light: For sewing lightweight fabrics such as
cotton, silk, or voile with A symbol
Medium: For sewing medium-weight fabrics such
as denim, canvas, or upholstery fabric with ‘’ M ‘’
symbol

USES/FUNCTIONS OF EACH PART

1.The Pressure Regulating Thumb Screw is used to
the pressure of the presser foot on the fabric,
allowing for precise control over the fabric’s
movement and tension during sewing.
2.The Thread Take-Up Level is used to adjust the
thread tension and control the amount of thread
taken up by the machine, ensuring a consistent and
even stitch.
3.The Bobbin Thread Winder is used to wind thread
onto the bobbin, preparing it for use in the sewing
machine’s lockstitch mechanism.

The Switch Regulator controls the machine’s
speed and stitch length, allowing the user to adjust
the sewing machine’s settings for different fabrics
and sewing tasks.
The Backtrack Level is used to control the reverse
stitching function, allowing the user to set the
number of reverse stitches and secure the thread at
the beginning and end of a seam.
The Oscillating Hole (also known as the Lucrating
Hole) is the opening through which the bobbin
thread passes, allowing the hook to catch and form
the lockstitch.
The Face Plate is the metal cover on the front of
the sewing machine that protects the internal
mechanisms and provides a smooth surface for the
fabric to glide over as it is being sewn. It may also
have markings or guides to help with alignment and
stitching.
The Pressure Foot is a metal plate that holds the
fabric in place and applies pressure to ensure
smooth and even feeding of the fabric during
sewing, preventing slipping and bunching.
The Thread Tension Control is used to adjust the
tension of the upper thread, ensuring proper
stitching and preventing issues such as loose or
tight threads, puckering, or thread breakage.
The Slide Plate is a movable plate that allows
the user to easily access the bobbin area, making it
simpler to remove and replace the bobbin, and to
clean the machine.

USES OF LOCK STITCH SEWING MACHINE

A lockstitch sewing machine is a versatile and
essential tool for various applications, including:

Garment construction: Lockstitch machines are
widely used in the garment industry for sewing
clothing, dresses, and other apparel.
Home decor: They are ideal for sewing curtains,
pillowcases, and other home decor items.
Upholstery: Lockstitch machines are used for
sewing heavy fabrics, such as upholstery, canvas,
and denim.
Repair and alteration: They are perfect for
repairing torn seams, hemming pants, and making
alterations to existing garments.
Quilting: Lockstitch machines are used for piecing
and quilting layers of fabric together.
Crafting: They are suitable for sewing crafts, such
as bags, wallets, and other accessories.
Industrial applications: Lockstitch machines are
used in various industries, such as automotive,
aerospace, and medical, for sewing heavy-duty
materials.
Leatherwork: They can be used for sewing
leather goods, such as belts, bags, and shoes.
Sailmaking: Lockstitch machines are used for
sewing sails and other heavy canvas materials.
The lockstitch sewing machine is a reliable and
efficient tool for a wide range of applications,
making it an essential asset for any sewer, crafter,
or industry professional.

BENEFITS

1.Bottom thread detection
It accurately detect the balance bottom thread in
the hook when the thread is less than 30cm.the
machine will stop and alarm to remind.

300mm/130mm space suitable for sewing
cotton cloth, down jacket, curtain, suit, manual
template etc

MAINTENANCE FOR A LOCKSTITCH SEWING
MACHINE

Regular cleaning: Remove lint and debris from
the machine’s interior and exterior.
Oil regularly: Lubricate moving parts to prevent
friction and wear but not all part need oil like
this sealed part in the diagram below which is
called the The oil pan is sealed, preventing dust

from entering, keeping the machine clean and
durable, ensuring perfect lubrication.

The head is dry, the needle bar in black DLC
(treatment that is used to give high hardness and
wear resistance) is lubricated with grease.
And also use high quality mineral grease for
lubrication with sealed oil tank preventing dust and
thread lint to enter the machine body

3.Thread take-up lever maintenance: Clean and
oil the thread take-up lever to ensure smooth
thread movement.

4.Bobbin winder maintenance: Clean and oil the
bobbin winder to prevent thread tangles.

5.Needle maintenance: Regularly replace needles
to prevent breakage and poor stitching.

6.Tension adjustment: Regularly check and adjust
thread tension to prevent puckering or loose
stitches.

7.Check and replace parts: Regularly inspect and
replace worn or damaged parts, such as the
presser foot or feed dogs.

8.Store properly: Keep the machine in a dry, cool
place, covered and protected from dust.

9.Follow manufacturer’s instructions: Refer to
the user manual for specific maintenance
recommendations for your machine. Regular
maintenance ensures optimal performance,
prevents issues, and extends the machine’s
lifespan.

SAFETY MEASURES

When operating a Jack A6 lockstitch sewing
machine, take the following safety measures:

Read the manual: Familiarize yourself with the
machine’s instructions and guidelines.
Keep children away: Ensure children are at a safe
distance to avoid accidents.
Use proper lighting: Ensure adequate lighting to
see the machine and fabric clearly.
Keep the machine stable: Ensure the machine is
placed on a stable, level surface.
Use the correct needle: Use the recommended
needle type and size for the fabric being sewn.
Keep fingers away: Keep fingers at least 6 inches
away from the needle and moving parts
Use the presser foot: Keep the presser foot down
to prevent fabric from getting caught under the
needle.
Keep the machine clean: Regularly clean the
machine to prevent dust and debris build-up. Use
the recommended thread type and size for the
fabric being sewn.
Avoid overloading: Don’t overload the machine
with too much fabric or thread. Regularly oil and
maintain the machine to prevent mechanical issues.
Turn off when not in use: Switch off the
machine when not in use to prevent accidental
start-ups.
By following these safety measures, you can
minimize the risk of accidents and ensure safe and
efficient operation of the Jack A6 lockstitch sewing
machine. Long press of this button will reset the
factory
Using oil window and oil alarm to double
remind real time monitoring of machine oil
quantity to avoid machine jam. Add the oil on
top no need to turn over the machine

QUESTIONS

FROM THE DIAGRAM BELOW CHOOSE THE CORRECT COMPONENT FROM (I)
TO (X)

1)The component labeled (I) is known as ______________ (A) Bobbin thread winder (B) switch regulator (C) pressure regulating thumb screw (D) thread take_up lever

2)The component labeled (ii) is known as _____________
(A) Backtrack lever
(B) lubricating hole
(C) slide plate
(D) thread take up lever
3)The component labeled (iii) is known as_____________ (A) Bobbin thread winder (B) switch regulator (C) backtrack lever

4)The components labeled (iv) is known as ______________
(A) pressure foot
(B) switch regulator
(C) Bobbin thread winder
(D) face plate

5)The component labeled (x) is known as_________________

(A) thread tension control (B) switch regulator (C) slide plate (D) pressure foot

6) The component labeled (ix) is known as ______________
(A) pressure foot
(B) thread tension control
(C) None of the above
(D) Oscillating hole

7)The component labeled (vii) is know as ______________
(A) lubricating hole
(B) oscillating hole
(C) A&B
(D) None
8) The component labeled (v) is known as______________

(A) lubricating hole
(B) pressure regulating thumb screw
(C) Bobbin thread winder
(D) face plate

9)The component labeled (vi) is known as _____________
(A) oscillating hole
(B) face plate
(C) slide plate
(D) Backtrack lever
10)The component labeled (viii) is known as_____________

(A) face plate
(B) slide plate
(C) Thread tension control
(D) Thread Take up lever

PART B

Pick the right option in each question

Who invented the first lockstitch machine in
1874?
(A) Allen B. Wilson
(B) Isaac Singer
(C) Elias Howe
(D) Thomas Edison
What type of stitch does a lockstitch machine
create?
(A) Running stitch
(B) Backstitching
(C) Lockstitch
(D) Embroidery stitch
What is the lockstitch characterized by?
A) Complexity, weakness, and in flexibility
(B) Simplicity, strength, and flexibility
(C) low, efficiency, and durability
(D) None of the above
What is the purpose of the rotating hook in a
lockstitch machine?
(A) To create a straight stitch
(B) To create a lockstitch
(C) To cut the fabric
(D)wind the bobbin
In what year was the first lockstitch machine
invented?
(A) 1850
(B) 1874
(C) 1890
(D) 1910
What type of sewing machine is a lockstitch
machine?
(A) Overlock machine
(B) Coverstitch machine
(C) Oscillating hook machine
(D) Chainstitch machine
What is the result of the lockstitch machine’s
stitching process?
(A) A weak and unreliable stitch
(B) A strong, flexible, and reliable lockstitch
(C) A slow and inefficient stitch
(D) A complex and difficult stitch
What is the purpose of the Light/Medium
Selector feature on some lockstitch machines?
(A) To adjust the machine’s speed
(B) To adjust the machine’s settings for sewing
different weights of fabric
(C) To adjust the machine’s thread tension
(D) To adjust the machine’s needle size
How many settings does the Light/Medium
Selector typically have?
( A) 3
(B) 2
(C) 4
(D) 5
What type of fabrics is the “Light” setting
suitable for?
(A) Heavyweight fabrics like denim and canvas
(B) Lightweight fabrics like cotton, silk, or voile
(C) Medium-weight fabrics like upholstery fabric
(D) All types of fabrics
What symbol is typically used to represent the
“Light” setting?
(A) M
(B) A
( C) L
(D) +
What type of fabrics is the “Medium” setting
suitable for?
A) Lightweight fabrics like cotton and silk
(B) Medium-weight fabrics like denim, canvas, or
upholstery fabricl
(C) Heavyweight fabrics like leather and vinyl (D)
All types of fabric
What is the purpose of the Pressure Regulating
Thumb Screw?
(A) To adjust thread tension
(B) To control fabric movement and tension
(C) To wind thread onto the bobbin
(D) To adjust stitch length
What does the Thread Take-Up Level control?
A) Thread tension
(B) Fabric movement
(C) Stitch length
(D) Bobbin winding
What is the function of the Bobbin Thread
Winder?
( A) To adjust thread tension
(B) To wind thread onto the bobbin
(C) To control fabric movement
( D) To adjust stitch length
What does the Switch Regulator control?
(A) Thread tension
(B) Fabric movement
(C) Machine speed and stitch length
(D) Bobbin winding
What is the purpose of the Backtrack Level? (A) To adjust thread tension
(B) To control reverse stitching
(C) To wind thread onto the bobb
D) To adjust stitch length
What is the Oscillating Hole also known as?
(A) Lucrating Hole
B) Bobbin Hole
(C) Thread Hole
(D) Stitch Hole
What is the function of the Face Plate?
(A) To protect internal mechanisms
(B) To wind thread onto the bobbin
(C) To control fabric movement
D) To adjust thread tension
What is the purpose of the Pressure Foot?
(A) To apply pressure to the fabric
B) To wind thread onto the bobbin
( C) To control thread tension
(D) To adjust stitch length

PART C

Fill in the gap

What is the first step in operating a Jack A6
lockstitch sewing machine safely? –_____________
Why should children be kept away from the
sewing machine? –____________
What is essential for clear visibility while
operating the sewing machine? –___________
How should the sewing machine be placed to
ensure stability? –_
What is crucial for sewing different fabrics on
the Jack A6 lockstitch machine? –__
How far should fingers be kept away from the
needle and moving parts? –______
What prevents fabric from getting caught under
the needle? –________
Why is regular cleaning of the sewing machine
important? —____________
What should be avoided to prevent mechanical
issues with the sewing machine? _____________

What does the Thread Tension Control adjust?

What is the purpose of the Slide
Plate?______________________
What is the result of adjusting the Pressure
Regulating Thumb Screw?__________
What is the effect of adjusting the Thread Take-Up Level?____________
What is wound onto the bobbin using the
Bobbin Thread Winder?___________
What settings can be adjusted using the Switch
Regulator?________
What is the purpose of the Backtrack Level in
reverse stitching?________
What is the name of the metal cover on the
front of the sewing machine?______
What is the function of the Pressure Foot in
preventing fabric slipping and
bunching?____________
What is the recommended distance to keep
your fingers away from the needle and moving
parts?____________
What should you do to the machine when you
are not using it to prevent accidental start-ups