Lock Stitch – Stop Seams Unraveling Fast

Lock stitch prevents seams from unraveling or stretching at the ends. It is an alternative to backstitching and is better for fine fabrics and sewing darts. Lock stitch ends are less bulky and equally secure, and do not change the drape on the fabric edges. A lockstitch is usually done on a sewing machine, but this tutorial will also cover embroidery or hand lockstitching.

What is Lockstitch?

Lockstitch is a type of stitch for sewing seams. Whenever you set your machine to make a simple straight stitch or zigzag stitch, you can start and finish with a lock stitch. 

Learn more about essential sewing machine stitches for beginners.

One of the most important purposes of this stitch is to secure the beginning or end of the sewing to stop the stitches from unraveling. This is a particularly good way to secure the seam on fine fabrics, where a double set of stitches going back and forth would show and look ugly. Lock stitch is useful when sewing quilt blocks to reduce bulk and to make the back of the quilt more attractive.

The lock stitch, using smaller stitches, and tying a knot at the beginning and the end, ensures a neat and secure finish to the starting point and the end of the seam.

How to Sew Lock Stitch (Step by Step)

If you have a mechanical or industrial sewing machine, it will not have an automatic lock stitch function. Here is how to sew a lockstitch with a simple adjustment to the stitch length.

1. Start with small stitches (L 0.5 or less) and sew two to four stitches on the spot as a way of jamming the stitches together. 
2. Adjust the stitch length to suit the fabric (most are L2.5) and sew normally until the end.
3. Lockstitch at the end of the seam.

Alternative Way to Lock Stitch with a Knot

A lock stitch that needs extra securing may be ‘locked’ by hand after the stitching has been started. This is a time-consuming method if you are in a hurry to finish your garment, but for fine fabrics and delicate seams, this is a sure way of locking the threads and keeping the seam secure.

1. Leave a tail of thread at the beginning and the end of the line of stitching. 
2. Pull the top end of the thread through to the wrong side of the fabric. 
3. Use the point of a pin to pull the loop through so there are two threads visible on the wrong side of the fabric. 
4. Knot these together on the wrong side of the fabric. 

Lockstitch vs Backstitch

Lockstitch gives a less bulky end than backstitch. Compare these 2 examples. See how the backstitch has the ends with 3 layers of stitching. When backstitching, you will start, go forward and stitch a few stitches, then reverse and go forward again. In comparison, lockstitch has no reverse stitching. The ends are secured by tiny stitches that are hard to unravel.

Embroidery Lock Stitch

Lock stitch, used as a hand stitch, makes a very simple foundation for a border in an embroidery pattern. The stitch itself is a basic stab style stitch making straight parallel stitches the same distance apart. Lock stitch can be used as part of a curved border as the stitch direction makes a subtle curve across the pattern or edging of the embroidery design. 

1. Create a base row of straight stitches between two lines. Change color.
2. Bring the new color up on the left of the first stitch.
3. With the thread above the needle, insert the needle under the first stitch from right to left.
4. Move to the next parallel stitch (blue). Insert the needle under the stitch, making sure that this time the thread is below the needle.
5. Continue in this fashion across the row.

Lock Stitch on the Sewing Machine

A lock stitch is a built-in feature of some computerized machines. This is called an automatic lock stitch. It will have the ability to start small with a single stitch moving forward and backward. The best way to navigate this stitch on a new machine is to consult the sewing machine manual and find out how the stitching mechanism works.

Lock Stitch FAQs

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Lock Stitching – In Conclusion

A lock stitch will prevent the ends of your seams from unraveling. It creates strength and durability while reducing bulk in delicate and fine fabrics. If you start simple with this basic stitch you will soon be locked into the joys of sewing and easily move on to other stitches and uses of your sewing machine. 

For a complete overview of hand and machine sewing stitches, explore the full types of sewing stitches guide.

Here are more seams to discover

• Types of Seams
• Fell Seams
• Slot Seams
• Lapped Seams
• Pinked Seams