The stitch length setting is a basic function of any sewing machine, and most patterns will advise that you change the setting at least once during the construction process. The type of seam, thread, and even fabric can all impact the ideal stitch length, which in turn will affect how well the garment holds up over time. But what are the pros and cons of longer or shorter stitches, and how do you know when each setting is appropriate for your project?
What is the stitch length?
Simply put, the stitch length setting determines how much fabric is pulled through and sewn on the machine between each stitch. It is almost always measured in millimeters, although occasionally you see it referenced as stitches-per-inch. For this post, we will be using millimeters since this corresponds with the settings on most sewing machines. This means that a 2.5 stitch length setting will sew stitches that are 2.5 mm long, and a 5 stitch length setting will sew stitches that are 5 mm long. A stitch length setting of 0 will stitch in place.
How to Change Your Stitch Length
Sewing machines will vary in both how this setting is changed, and the range of stitch lengths offered. While most machines will go up to at least a 4 or 5 mm length, some machines (like our studio Pfaffs) can go up to a 7 mm length.
Luckily, because stitch length is such an important and basic setting it is usually an easy one to find and change on your machine. If you have a manual or vintage machine, the setting is likely to be located on a dial or knob on the front of or the top of your machine. Note that this should not be confused with the stitch width setting, which is often nearby and demarcated with a zigzag-shaped line.
On computerized machines, like the Pfaff Quilt Expression shown here, you can find the setting located front and center on the touchscreen. We love a computerized machine for this because it not only gives us exact precision when choosing a stitch length, but it also has the capability to save our settings for specific fabrics and techniques like the ones we will discuss below.
Learning to sew can feel like learning a new language, and the vocabulary dedicated to various stitch techniques is no exception. Here are some common terms and what they mean for you stitch length settings:
Standard stitch length: Refers to a 2.5 mm stitch length. Commonly used for regular seams when assembling two pieces of fabric. This is considered the “default” stitch length unless otherwise noted, but you may choose to change your standard stitch length for a particular project if the fabric or technique calls for it.
Topstitching: Decorative stitches placed on the exterior of garments such as jackets and pants. This are typically sewn parallel to existing seamlines, but not always. Topstitching requires a longer stitch length because of the extra layers of fabric and heavier-weight thread used (optional). For lightweight fabrics we recommend a setting of 3 mm, and for mid- to heavyweight fabrics a setting of 3.5 mm.
Staystitching: A line of stitching sewn just inside of the intended seam line of a pattern piece to prevent future stretching and distortion. Staystitching is typically around necklines, armholes, and any other bias cut angles. Using a shorter stitch length here will help secure the fabric further and keep it from stretching. For this application, we recommend a setting of 2 mm.
Basting: Also known as tacking, these are long stitches used to temporarily hold fabric in place for fitting or added precision around tricky-to-sew areas like necklines and armscyes. A longer stitch length is ideal for basting because the seam will be faster to sew and the thread easier to remove later. For areas that require more accuracy (like the a fly front on a pair of pants), we recommend using a setting of around 4 mm. For other seams, feel free to go all the way up to the max offered by your machine.
When it comes to different sewing techniques, adjusting the stitch length appropriately can have a huge impact on the final result. Here’s what you need to know about stitch length for some of the most common sewing skills:
Gathering: The longer the stitch length, the easier and faster it will be to pull the fabric along the gathering threads. However, the shorter the stitch length, the easier it will be to achieve even gathers. We find a 4.5 mm setting to be a good compromise, but it’s always a good idea to test and see what you prefer. We have a full post dedicated to gathering here.
Darts: In general, darts should begin with a longer stitch length, and gradually decrease in stitch length as you sew towards the end or “point” of the dart. We like to begin darts with a standard stitch length (2.5mm) and gradually decrease until the last couple of centimeters are finished with a shorter stitch length (1.5 mm). Since there is no backstitching at the end of a dart, this helps secure the stitches and prevents bubbling.
Curves: Shortening the stitch length is an easy way to achieve a smoother result when sewing curved seams (like the pockets of the Acajou pants). Longer stitches leave less room for error and can make curves appear more angular. When approaching a curve, try shortening the stitch length by 0.5 mm to make sewing easier.
The guidelines above are all general rules of thumb, but it’s equally important to consider the fabric itself and adjust accordingly when choosing a stitch length.
Lightweight fabrics: Have you even sewn a delicate fabric only to be frustrated that is gathering and puckering when stitched? A shorter stitch length can help prevent this. For lightweight fabrics, a 2 mm setting for standard seams can improve your results.
Thick fabrics: Heavyweight fabric like denim can require a longer stitch length to get through multiple thick layers. In these instances, try increasing to a 3 mm setting for standard seams.
Fabrics prone to holes: Some materials like leather, vinyl, or suede can produce permanent holes with every stitch. Unlike regular fabric where the stitches will pass through the weave of the fibers, these holes can actually weaken the integrity of the material. To create a sturdier seam, use a longer stitch length to reduce the overall number of holes.
Stitch length is a basic setting on any machine and can often be overlooked in the flow of an exciting sewing project. However, taking the time to consider and select the appropriate stitch length will not only make your sewing easier, it can also help your projects turn out better! We hope that these tips and tricks taught you something new, and will help you tackle your next project with confidence and ease.