Mastering Techniques for Sewing Knits

To achieve a smooth seam finish, it's essential to avoid stretching the fabric before or after the needle. Simply guide the fabric and let the machine do the work. By using the right stitch types, you can ensure that your seams will stretch appropriately with the fabric.

Needle Selection

Use a ballpoint, jersey, or stretch needle. These needles have a rounded tip that prevents snagging, skipped stitches, and damaging the knit fabric. For thread and needle size pairings, check out our Zero to Hero Guide

Stitch Type

• Stretch Stitch Many newer sewing machines have a built-in stretch stitch, which allows the fabric to stretch without breaking the thread. This stitch resembles a straight stitch when sewn with narrow stitch width.
• Zigzag Stitch A narrow zigzag stitch (width of 0.5-1mm, length of 2.5-3mm) can also be used to allow the seam to stretch.

Stitch Settings

• Use a slightly longer stitch length (around 3mm) to prevent puckering.
• Reduce the presser foot pressure if your machine allows, to prevent stretching out the fabric as you sew.
• A walking foot attachment may help to feed multiple layers evenly with less stretch.

Seam Finishing

• Overcasting Use an overcast stitch or a zigzag stitch close to the raw edge to prevent fraying.

Sewing Machine

• Single Fold Hem Fold raw edge to wrong side once, stitch with stretch or zigzag.
• Double Fold Hem Fold the raw edge twice, concealing the raw edge, and stitch close to fold with stretch or zigzag.
• Twin Needle For a nice hem finish, use a twin needle to create parallel rows of stitching on the right side, which mimics a cover stitch. Lightweight knits can "tunnel" when sewn with a twin needle, so be sure to consult your machine's manual for the correct settings.

Serger

• Serge Raw Edge and Single Fold Hem Fold serged edge to wrong side by 5/8 inch (1.6cm), stitch close to fold with twin needle or stretch stitch.
• Advanced serger options include a serger blind hem or mock flatlock hem. Refer to the settings and techniques in your machine's manual.

Coverstitch Machine

This specialty machine creates professional hems with parallel stitching on right side, serged finish on wrong side, and is ideal for knit hems and cuffs.

Tip Using spray starch or a washable school glue stick helps the hemline hold a crisp press and stabilizes your hemline during construction.

A sewing machine is capable of sewing knit fabrics with moderate stretch (30-50% stretch) and a serger is not required for those materials. However, when working with fabrics that have high elasticity (over 60% stretch), a serger is essential for a few key reasons:

Stretch and Durability

Sergers create strong, flexible seams that can withstand the significant stretching and movement of highly elastic fabrics. Traditional sewing machines might struggle to produce seams that can handle the stress without breaking.

Professional Finish

Sergers trim, sew, and finish the fabric edges in one step, resulting in clean, professional-looking seams that resist fraying. This is particularly important for stretchy fabrics, which can fray or curl easily. With dual feed dogs and differential feed rates, a well tuned serger eliminates wavy or overstretch seams.

Efficiency

Sergers sew at high speeds and handle fabric edges efficiently, saving time and effort. This is especially useful when working with fabrics that can be difficult to manage due to their stretchiness.

Seam Stretchability

The serged seams are highly stretchable, maintaining the fabric's elasticity and ensuring the garment can move with the body without the seams restricting movement or causing discomfort.

Therefore, using a serger for fabrics with more than 70% stretch is crucial to achieve durable, professional, and flexible seams that can handle the unique properties of these materials.

Recommended Sergers

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• Brother 1034d
• Juki MO654DE
• Bernette b44

Needle Selection

Use Ballpoint or Stretch Needles These needles have a rounded tip that prevents snagging and damaging lightweight knit fabrics.

Stitch Type

• 4-Thread Overlock Stitch Ideal for constructing lightweight knits, this stitch type provides both strength and stretch, accommodating the fabric's natural elasticity without breaking.
• 3-Thread Overlock Stitch Useful for finishing edges on lightweight knits, this stitch is less bulky and works well for finishing raw edges after sewing a seam.

Stitch Settings

• Stitch Length Set the stitch length to around 3mm to prevent puckering. Lightweight fabrics can bunch up easily, and a slightly longer stitch helps avoid this.
• Presser Foot Pressure Reduce the presser foot pressure if your serger allows. This helps prevent stretching the fabric out of shape as you sew.

Beginner Tips for Sewing with a Serger

• Practice on Scraps Before sewing your actual project, practice on scraps of your lightweight knit fabric. This helps you get a feel for the fabric and make any necessary adjustments.
• Test Stitches Always test your stitches on a scrap piece to ensure the tension, stitch length, and differential feed are correctly set for your fabric type.
• Use Differential Feed If your serger has a differential feed, use it to control fabric stretch and prevent wavy seams on lightweight knits.
• Stabilize Hems Use a water-soluble stabilizer or tissue paper under the fabric when hemming to prevent the fabric from stretching out of shape.
• Go Slow While sergers are fast, taking your time with lightweight knits can help avoid mistakes. Control the fabric carefully as you sew to ensure smooth, even seams.

Mastering sewing with knits opens up a world of possibilities for creating comfortable, stylish garments. With these tips and techniques, you'll be well on your way to sewing knit fabrics with confidence and achieving professional results. Happy sewing!