What is lockstitch sewing machine

What Is Lockstitch Sewing Machine?

A lockstitch uses a seam to create a strong and durable connection between two pieces of fabric. before you begin stitching, stretch your fabric, since your fabric can be tight when you first started.  Lockstitches are often used in areas where there is a lot of strain on the material, such as, around zippers or buttons. You have to use plenty of thread so that your seams don’t start to show through after you have finished stitching them together.

Lockstitch sewing machine works in five basic steps: pick, place, and align. Sew and dispose of. Two or three different plies of the same shape or different shapes are picked up one by one by the operator. These plies are then placed on the bed of the machine with the end to be sewn near or under the presser foot. Lockstitch sewing machines are used for a wide range of materials, including fabrics and synthetics. In this article, we have discussed in detail the lockstitch sewing machine, its different features, characteristics, functionality, maintenance, etc.

Key Takeaways

  • We have gone through an overview of the lockstitch sewing machine.
  • Different types of lockstitch sewing machine.
  • The functionality of the lockstitch sewing machine and its maintenance.

Lockstitch Sewing Machine Explained

Lockstitch sewing machine explained
Lockstitch sewing machine explained

A lockstitch sewing machine will bind cloth together with two spools of thread and a needle with an eye to the base. A lock stitch sewing machine is different from a chain stitch sewing machine, it will make strong, straight seams. It is a commercial sewing machine. It has a wide variety of applications. This machine works by interlocking two threads from two bobbins. The length of the stitch and the firmness can be controlled by a dial. The first spool will sit on top of the machine. The thread runs through a tension arm to feed it smoothly. The needle is attached to a foot which will press the fabric against a feed. The second thread is hidden in a compartment beneath the foot. the second thread will get pulled on a shuttle to loop around the thread from above.  The needle stitches up and down by a manual foot treadle or a motor controlled by a pedal.

It took decades to perfectly build an automated lockstitch sewing machine. In 1846, Elias Howe first thought of looping one thread through another, while the hand-operated needle would stitch back and forth. After getting a patent, he never engineered or marketed it successfully. In the 1850s, Isaac Singer improvised the machine, then built a machine where the needle moved up and down, the crank was controlled by foot, so hands could be free to sew the cloth. He then perfected the second shuttle which sits underneath to control the bobbin. A modern lockstitch sewing machine has convenience, strength, and flexibility. They are computerized, so the foot pedal controls the stitching with a motor. With the proper settings, it will let you do them, quilt, form buttonholes, embroider decorative seams, straight seams, etc. It supports spools of different sizes, fabric of various thicknesses, and other customized projects.

How Does It Work?

Lockstitch sewing machines produce lockstitches, which are created when the upper thread (from the spool on the top spindle) and the lower thread (from the bobbin) interlock or twist together as they pass through the hole which is created by the needle. The stitches on top of the fabric will appear the same as those on the bottom. Lock stitch sewing machines can create zigzag stitches which are very helpful for hemming fabrics or for doing buttonholes, they are also useful for stitching stretchy fabrics.

Types of Lock Stitch Sewing Machines

Types of lock stitch sewing machines
Types of lock stitch sewing machines

It has different types for a variety of needs. For industrial purposes- A class 7 machine with ¾’’ foot lift is one example. For medium and light-duty use, you will get drop feed machines, if you want to do versatile stitching, you will need walking foot machines. To get your job done properly, it is essential to find the right lock stitch machine. When you are making your purchase, you should also consider features and specs which will suit your needs. Lockstitch is created when a rotary hook will catch a needle thread loop since it goes around the bobbin and interlocks two threads. This type of stitch can be used in clothing and upholstery fabrics.

In the garment factory, there are two types of lock stitch sewing machines used.

1. Single needle lockstitch machine.

2. Double (two) needle lockstitch machine.

1. Single needle lock stitch machine

A single-needle lock stitch machine is stitched by one needle of a machine by lock stitch. A single needle lock stitch machine is called a plain needle sewing machine. A single needle lock stitch machine is used for industrial sewing machines. Today you will get a single needle lockstitch with thread trimmer which will operate at the highest speed.

2. Double – Needle lock stitch machine

Double-needle/ twin/ two needles is a needle with a single shank and two shafts, when you proceed stitching with double stitching, you will get two parallel rows on the face of the fabric and a zig-zag stitch on the back of the fabric.

3. Using a lock stitch sewing machine – What to expect

There are some common things that you will come across when using a lock stitch sewing machine in terms of setting it up, the different functionalities it has, proper maintenance, and when to properly replacement of it when needed. Here are all of these things mentioned below in more detail.

4. Setting


The setting of the lock stitch machine is very important. Before running the machine, you have to ensure that the machine has the right setting.

  1. Stitch Density Controller: it will control the no of stitches per inch. Stitches per inch are determined by rotating the knob and fixing the knob at the correct position.
  2. Motor: The speed of the machine is determined by Motor rpm. The speed will be controlled by tightening or loosing the belt over the machine and machine pulley.
  3. Needle: The needle will go accurate setting to ensure proper sewing. The needle will be attached utilizing a screw which will need to be tightened to sew easily. Also, the needle size is important to avoid tearing onto the fabric.
  4. Pressure Foot: the type of pressure foot you are going to use and the proper setting of it is also important, which will ensure the attachment of the moor through the machine pulley.
  5. Feed Dog: when you are working randomly, the feed dog will be loose which may cause an accident. The feed dog must be set properly with a screw.

5. Functionality


Lockstitch sewing machine is most commonly used in homes and also for educational purposes. It runs on foot and can be converted to an electric power machine when it is needed. This machine is tricky to use, but with some practice, it becomes easier. It is a very strong machine, with a correct combination of thread and fabric, and it can be used for most purposes. It has a limited bobbin thread length which means you will need to change the bobbin from time to time. This is a perfect machine for repairing garments or altering them.

For sewing light and heavy fabrics, such as all kinds of plain sewing, you have to thread a needle and tie off the end of the thread. You can make a loop by taking the thread around your fingers, then pulling the thread through the hole you made. Hold onto one side of the fabric so that you don’t lose it as you make another loop, this time you will cross over from where you started. Pull tight on both ends of your new loop, so that, they are even with each other; they will look like two vs facing each other.

When it is needed, cut away excess fabric. Trim enough so that there is about a 1/8’’ overlap between loops when closed up again – don’t cut too close or else you will have a big hole. When you are using a hi-speed lockstitch machine which has a heavy-duty operation and features an auto lubricating system, so that, it can sew thin materials without wrinkles and thick materials without breaking threads possible.

This machine has a reverse feed mechanism that can sew thin material easily without breaking the thread, it can also sew thicker material without any breaks as well. High speed of operation makes this machine ideal for all kinds of sewing projects whether it is for lightweight projects or heavy-duty projects, so it makes motorcycle helmets or car upholstery perfectly. It has a sleek appearance, too.

A lockstitch will create a strong seam that will stay for a longer time. It is perfect for beginners and can be used on most fabrics and in most sewing projects. Make sure your thread size is correct and check the manufacturer’s instructions before you start your projects.

6. Maintenance


It has different types of maintenance. We have given the important ones below:

1. Routine maintenance: For routine maintenance, you need to do lubrication and regular inspection. When you are lubricating your machine, it will ensure the long life of the machine and all the equipment will work safely. When you are inspecting the machine, you are trying to detect faults in the equipment, so that, if repairs and replacements are needed, they will be taken at the right time.

2. Schedule maintenance: you will get this type of maintenance for inspection, overhaul, lubrication, and servicing of the machine. For this, you need to open the machine into the smallest components to carry out lubrication.

7. Replacement


If your machine is prone to break, a replacement will be needed. Even after repair, the components may become obsolete which will affect the production or sometimes they expire, in these situations, you will need to replace your parts. Replacement parts are needles, pressure feet, feed dog, etc. need frequent replacement.

Precautions: you need to take the following precautions, when you need to repair, do maintenance or you need to do replacement.

  1. All repair and maintenance should be done by switching off the machine.
  2. During replacement, the right tools should be placed on the right side.
  3. You need a skilled person for doing the maintenance and replacement.
  4.  You should handle all the components very carefully.
  5. You should tighten all the equipment properly.


1. What is a lockstitch sewing machine used for?

The Lockstitch machine is used for joining fabrics collars, cuffs, pockets, sleeves, facing, etc. Lockstitch type 301 is the simplest which is shaped from the needle thread and the bobbin thread.

2. Why it is called a lockstitch sewing machine?

The lockstitch uses two threads, an upper thread, and a lower thread. This is called lockstitch because the two threads, upper and lower, “lock” (entwine) together in the hole of the fabric which may pass through.

3. What are the 2 types of lockstitch sewing machines?

There are typically two types of lockstitch sewing machines-
1. Single Needle Lockstitch Machine: a single needle is used.
2. Double–Needle Lockstitch Machine: two needles are used with a single shank to give two parallel rows on the front of the fabric and a zigzag stitch on the back.

4. What is another name for a lockstitch sewing machine?

Lockstitches are also known as French seams or overlock seams.

Final Thoughts

In this article, we have discussed so far, different features and characteristics of a lockstitch sewing machine. Lockstitch sewing machine is usually used for industrial purposes. Given its features and characteristics, it can be used for household purposes, too, such as mending, alterations, hemming, etc. This sewing machine needs proper care and servicing, when it is needed, so that you can use your sewing machine for a longer time. Every time you start using your sewing machine, check if it needs any maintenance and inspect the parts of the machine for a new replacement.


Hey I’m Sherry Howes an expert in sewing, knitting, crocheting, and embroidery. With a passion for fiber arts and a talent for crafting, I Have spent years improving my skills and sharing knowledge with others. Whether teaching a class or creating a new project, I’m always excited to share my love of crafting with the world. I like researching new techniques and trends in the crafting arts community.

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