Lock Stitch - Stop Seams Unravelling Fast

Lock stitch has a way of sounding secure. We use locks all the time to keep ourselves locked in or undesirables locked out. Lock stitch is the basic sewing machine stitch that does exactly that. It locks into the fabric at every stitch and locks together before moving on making the stitch secure.

Sewing Lock Stitch

Whenever you set your machine to make a simple straight stitch or single zigzag stitch you are setting out to sew lock stitches. The locking takes place between the needle threads on one side of the fabric interlacing with the bobbin thread on the underside of the fabric.

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 beginning and end of the seam on fine fabrics where a double set of stitches going back and forth would show and look ugly. The lock stitch, using smaller stitches to start and finish, 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.

Automatic Lock Stitch

A lock stitch that is a built-in feature of some automatic machines 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 user’s manual and find how the stitching mechanism works.

Manual Lock Stitch

Method #1:

A machine without an automatic lock can simply start with small stitches and sew two to four stitches on the spot as a way of jamming the stitches together. This is done at the beginning and the end of the stitch line.

Method #2:

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.

• Remember to leave a tail of thread at the beginning and the end of the line of stitching. 
• Pull the top end of the thread through to the wrong side of the fabric. You do this by pulling the under thread and as you do so the top thread appears like a loop on the underside of the fabric. 
• Use the point of a pin to pull the loop through so there are two threads visible on the wrong side of the fabric. 
• You can knot these together or sew them with a double back stitch to the wrong side of the fabric. 

Pin

Advantages of a Lock Stitch

Lock stitch has the following simple advantages:

• Does not use a lot of thread.
• Does not tend to seam pucker.
• It is the threads of lock stitch that interlace to form a strong stitch.
• Looks the same on both sides of the fabric.
• Should not be compared with chain stitch.

Best Thread for Lock Stitch

It is important to use the right type of thread for your lock stitch. It is a strong stitch with great resilience and is used for large quantities of seams needing a single needle thread and single bobbin thread. 

When to Use Lock Stitch

The lock stitch is particularly useful for sewing situations where the front and the back of the sewing must look the same. Topstitching for cuffs and collars is a fine example of how a lock stitch can provide the same stitch front and back of the edging.

Lock Stitch on Sewing Machines

Lock stitch is the most widely used sewing stitch found on sewing machines.  It is the automatic stitching formed by repeated threading the upper thread through the needle down through the fabric to pick up or lock with the lower thread and together they form a series of straight stitches. Modern sewing machines may have a double lock stitch facility. A twin needle and double threads make this double lock stitch possible.

Lock stitch Used as an Embroidery Stitch

Lock stitch, used as a hand embroidery 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. 
2. Change color.
3. Bring the new color up on the left of the first stitch.
4. With the thread above the needle, insert the needle under the first stitch from right to left.
5. Move to the next paralel stitch (blue). Insert the needle uncer the stitch making sure that this time the thread is below the needle.
6. Continue in this fashion across the row.

Pin

Lock Stitch - In Conclusion

Beginners can master the lock stitch on a straight sewing stitch setting on an automatic sewing machine. Changing the length will enable the sewer to change the length of the lock stitch and try different effects with the stitch. 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.