This article was originally published on 16 July 2025 and was significantly updated by Gail Butcher on January 27, 2026, to include new step-by-step locking techniques, troubleshooting for modern machines, and expert tool recommendations.
If you’re just starting out with sewing, you’ll hear the term “locking stitch” pretty early on. It’s a simple but important sewing technique that helps secure the beginning and end of your stitches, so they don’t come undone after you finish sewing, because, as you know, there’s nothing more frustrating than a seam that unravels.
In the world of sewing, the term ‘lockstitch’ can be confusing. It refers both to the mechanical way your sewing machine creates a stitch and the specific technique used to tie off a thread at the beginning of a seam.
In this guide, I’m going to clarify what a locking stitch is, how it differs from a backstitch, and how you can use it to create professional, durable garments that will last and look great.
How To Find The Locking Stitch
There’s a locking stitch button (sometimes called a “tie-off” or “backtack” button). When you press it, the machine sews a few stitches forward, backward, or in place to “lock” the thread. It’s like tying a tiny knot with your machine instead of by hand.
A locking stitch sewing machine is helpful for:
- Sewing seams that won’t unravel
- Keeping your projects neat and strong
- Saving time (no need to backstitch manually!)
Sounds important to know, right? Ok, so let’s learn it together. So you don’t mix up lockstitch vs straight stitch sewing machine.
Table of Contents
What Is Lock Stitching?
A lock stitch on a sewing machine interlocks an upper thread with a lower thread right inside the fabric. This “locking” action is what makes the stitch strong and secure. The technique involves stitching over the first and last 1/2 inch of seam to lock threads in place.
- The Mechanism: Most modern sewing machines are technically “lockstitch machines,” meaning they use a needle thread and a bobbin thread that interlock inside the fabric.
- The Technique: A “locking stitch” (sometimes called a tie-off stitch) is an inconspicuous way to secure your thread without the buld of a traditional backstitch.
- International Terms: Depending on where you are, you may here this called a point noue (French) or a locksteek (Dutch).
It’s the most common type of stitch you’ll find used in both home sewing machines and industrial ones, because it holds up well and looks neat on both sides of the fabric, like edge stitching.
How to Lock A Stitch on a Sewing Machine (Step-by-Step)
To do a lock stitch on a sewing machine, follow these steps:
- Position Your Needle: Start at the very beginning of your seam line.
- Adjust Stitch Length: Set your stitch length to the smallest possible setting (around 0.5mm or “fine”).
- Sew 3-4 Stitches: Sew a few tiny stitches in place to “lock” the needle and bobbin threads together.
- Resume Normal Sewing: Change your stitch length back to your standard setting (usually 2.5mm) and continue your seam.
- Repeat at the End: When you reach the end of the seam, shorten the stitch length again for the final 3-4 stitches to tie off the thread.
1. Position Your Needle
Start at the very beginning of your seam line. I usually use a Universal 80/12 needle for medium-weight fabrics like cotton or linen. For lightweight fabrics (like voile or batiste), I switch to 70/10; for heavier materials (like denim), I go with 90/14.
I go with a good-quality all-purpose polyester thread. It’s strong, doesn’t break easily, and works great with lock stitches.
I also recommend good-quality micro-tipped scissors, as they allow you to cut threads flush against the fabric without nicking your work and a cleaning brush to help prevent lint building up in the bobbin race.
2. Adjust the Stitch Length
I set my machine to a standard stitch length of 2.5mm. It’s the sweet spot, tight enough to hold the seam, but not so tight it puckers the fabric. Being too tight can cause a jump stitch issue.
Once everything’s threaded and ready, I place my fabric under the presser foot, lining the edge up with one of the seam allowance guides (like the ⅝” or 1cm line) on the needle plate.
3. Sew 3-4 Stitches
Lower the presser foot and hold your fabric lightly in place. Sew forward 3 to 5 stitches. (This is just enough to anchor the thread.)
Hit the reverse button (or lever, depending on your machine), and sew backwards over those same 3 to 5 stitches. Release the reverse button and continue sewing forward along the seam as normal.
This back-and-forth creates a mini overlap of stitches. This is what “locks” the thread in place, so it won’t unravel.
4. Resume Normal Sewing
I guide my fabric gently without pulling or pushing, letting the feed dogs do the work. I watch the edge of my fabric and keep it lined up with the seam guide on the needle plate to keep it straight.
If I’m sewing something slippery (like silk), I’ll lower the stitch length slightly (maybe to 2.0mm), and if I’m topstitching, I might increase it to 3.0mm for better visibility.
Locking the End of the Seam
When I near the end of the seam, about ½ inch from the edge. I stop and prepare to lock it off. Sew until you’re just before the fabric ends.
Hit the reverse button again and sew backwards 3–5 stitches. Release the button and sew forward right to the edge. Now, just like the beginning, the end of my seam is locked down securely.
5. Repeat at the End
I make sure the thread take-up lever is at the top (the little hook that moves up and down). If it’s not, the machine may not have fully formed the last stitch, and I might end up fighting with the thread.
Then, I lift the presser foot and gently pull the fabric out toward the back of the machine. Finally, I snip the threads, leaving about 2–3 inches of thread tail.
And that’s it! You got your lock stitch on your sewing machine.
Locking Stitch vs. Backstitch: Which is Better?
While both a lockstitch and a backstitch will prevent your stitch from unravelling, they serve different purposes:
| Feature | Backstitch | Locking Stitch (Tie-off) |
| Method | Sewing backward and then forward | Multiple tiny stitches in one spot |
| Visibility | Noticable and slightly bulky | Nearly invisable |
| Best For | Heavy fabrics and standard seams | Delicate fabrics and topstitching |
Lockstitch Vs Straight Stitch: A Quick Distinction
It is common to hear the terms “lockstitch” and “straight stitch” used interchangeably, but they actually refer to different aspects of sewing:
The Connection: On most home machines, a straight stitch is created using a lockstitch mechanism.
Lockstitch is the Mechanism: This refers to the mechanical process where the top thread and bobbin thread interlock to form a secure bond.
Straight Stitch is the Result: This is the visual appearance of the stitch—a simple, straight line on the fabric.
While a straight stitch is a specific pattern, the “lockstitch” mechanism is what makes that pattern durable and permanent. For a deeper look at how these two differ in professional settings, see our full guide on [Lockstitch vs. Straight Stitch].
| Feature | Lockstitch | Straight Stitch |
| Definition | A sewing method where two threads (top and bobbin) interlock. | A single line of identical stitches without any zig-zag or decorative patterns. |
| Mechanism | Requires a bobbin and a rotating hook to catch the top thread. | Can be formed by lockstitch or chain stitch mechanisms. |
| Appearance | Looks identical on both the top and bottom of the fabric. | Appears as a continuous straight line on the surface. |
| Used in | Home and industrial sewing machines like an interlocking stitch. | Almost all sewing machines |
| Stitch appearance | Same on both sides | Appears as a straight line on the top |
| Durability | High; very difficult to unravel once secured. | Depends on the lock; if not “locked” at the ends, it can pull out. |
How to Lock a Stitch by Hand
If you are working away from your machine, knowing how to secure a hand lock stitch is essential for durability:
- The Anchor Knot: Start by making a small knot at the end of your thread before your first pass through the fabric.
- The “Back-and-Loop” Method: After your final functional stitch, take a tiny stitch backwards.
- Create a Loop: Before pulling the thread tight, pass your needle through the resulting loop twice.
- Pull to Secure: Pull the thread firmly to create a “knot” that sits flush against the fabric.
Troubleshooting: Which is My Lockstitch Machine Locking Up?
If your thread is bunching or the needle won’t move, check these common culprits:
- “Birdnesting”: This is usually caused by incorrect top tension. Raise your presser foot and re-thread the top path completely.
- Skipped Stitches: This is often a dull or bent needle. Replace your needle and ensure it is the correct type for your fabric.
- Machine Jams: Check the bobbin race for lint or thread scraps that may be “locking” the mechanism.
Frequently Asked Questions
How many stitches do I need to lock with?
I usually go with 3 to 5 stitches forward and backward. That’s just enough to secure the seam without making it bulky.
Do all sewing machines have a lock stitch or reverse button?
Most modern machines do. If yours doesn’t have a reverse feature, you can manually turn the fabric around and sew back over those first few stitches to achieve the same effect.
Can I use a lock stitch on all fabrics?
Yes, but you might need to adjust your needle size and stitch length depending on the fabric. For example, light cotton likes a 70/10 needle and 2.0–2.5mm stitch length. Denim? Go with 90/14 and 3.0mm.
What is the difference between a lockstitch and a straight stitch?
A lockstitch refers to the mechanical way your machine interlocks two threads (needle and bobbin) to form a stitch. A straight stitch is the visual result—a simple, linear line of sewing. Most home machines create a straight stitch using a lockstitch mechanism.
How do you lock a stitch without a backstitch button?
If your machine lacks a dedicated “lock” or “tie-off” button, you can secure your seam by reducing your stitch length to 0.5mm (or nearly zero) for the first and last 3-4 stitches. This creates a tiny, secure knot that is much less bulky than a traditional backstitch.
Is a lockstitch the strongest hand stitch?
While the machine-made lockstitch is the standard for durability, the backstitch is actually considered the strongest stitch for hand sewing because each stitch overlaps the previous one, providing maximum reinforcement.
What is a Baby Lock sewing machine?
Baby Lock is a high-end brand of sewing machines and sergers. While they produce standard lockstitch machines, they are most famous for their specialized overlockers that feature automatic air-threading systems.
Conclusion: Mastering the Lock Stitch
Locking your stitches might seem small, but it makes a big difference. It keeps your seams from unravelling and gives your projects a clean, strong finish. Once you get the hang of it, it becomes second nature. Just a quick step that makes everything last longer. It’s also the fastest way to elevate your sewing from “homemade” to “handmade”. Whether you choose the traditional backstitch for heavy-duty projects or the discreet locking stitch for delicate finishes, securing your seams ensures your hard work stands the test of time.
We want to see your projects! Did this guide help you solve a “locking up” mystery, or did you try the tie-off technique for the first time?
- Share Your Work: Tag us on social media and show off your perfectly secured seams.
- Got a Question? If your machine is still acting up or you’re confused about a specific stitch, contact Gail Butcher directly through our contact page or leave a comment below.
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Happy sewing, and remember: a secure start leads to a flawless finish!
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