Sewing in knit fabrics

This is a little introduction to knit fabrics. I've also gathered some tips for how to succeed when using a sewing machine for knit fabrics.

Knit fabric doesn't fray, which means that you don't have to finish seams, which you would do with woven fabrics. Neither does knit get wrinkly, as much as woven fabrics usually do. 

Knits shrink when washing for the first time, so you'll want to pre-wash the fabric before cutting into it.

Knit fabrics can have different amounts of stretch. Generally ribbing has a lot of stretch, while jersey and interlock has less. But it depends on if and how much lycra is in the fabric.

It's a good idea to evaluate the stretch of the fabric before sewing. For some sewing patterns the amount of stretch needed in the fabric is specified. 


Sewing in knit fabric with a sewing machine

When you're sewing in knit fabric an overlocker or serger is great to use. But it's not necessary and you can achieve really nice results with a regular sewing machine too. 

  1. Use the correct needle
    The most important thing is to switch out your universal needle on the sewing machine for a ballpoint/jersey or stretch needle (B). They have a rounded tip which won’t ruin the fabric. The same goes for your twin needle, if you’re using one. That one should also be ballpoint/jersey or stretch (A).
  2. Use a stretch stitch
    This is really important, especially for horizontal seams where stretch is needed (e.g. the neckline). A seam that doesn’t require much stretch, e.g. vertical seams such as the side seams, can be sewn with a narrow zigzag stitch.
    A: Overlocks seam, for that you will need an overlocker/serger. 
    B: Narrow zig zag stitch (approx. 1,5 mm wide and 1,5 mm long). 
    C: Wide zig zag stitch (approx. 2,5 mm wide and 2,5 mm long).
    D: Twin seam (switch out the needle for a twin needle, and use a stitch length of approx. 3).

  3. Don’t pull the fabric
    Try not to pull the fabric as you’re sewing. That generally results in a “bubbly” seam. Neither should you let the fabric hang down from the table. Lift it up so that it can be easily fed into the machine.
  4. Press seams
    Always press a seam after you’ve sewn it. Don’t wait until the entire garment is finished. Pressing is often the thing that takes away that “homemade” look and gives the garment a professional feel. When you’re pressing, the thread “melts” into the fabric.
  5. Use a walking foot
    If none of the above helps you could try switching to a walking foot (C) instead of a regular presser foot (D). It keeps the fabric from stretching as you sew.