You need three sewing machine stitches for almost every garment: a straight stitch with adjustable length, a zigzag with adjustable width and length, and a buttonhole. Add a stretch stitch for knits, a three-step zigzag for elastic and seam finishing, and a blind hem stitch if you hem trousers often, and you have covered what a dressmaker uses in a year. The other 50 or 100 stitches on the dial are decorative and optional.
| Stitch | What it is for | Typical setting |
|---|---|---|
| Straight | Seams, topstitching, basting, gathering | 2.5 mm; 3 to 3.5 mm on thick fabric; 4 mm or more for basting |
| Zigzag | Finishing raw edges, appliqué, sewing on elastic, a stretchy seam in a pinch | 2 mm wide, 2 mm long for edges; 5 mm wide for elastic |
| Buttonhole | Buttonholes, one-step or four-step | Length set by the button |
| Stretch (lightning) | Seams in knits that must stretch | Width 1 mm, length 2.5 mm |
| Three-step zigzag | Elastic, swimwear, finishing fabrics that tunnel under a plain zigzag | 5 mm wide, 1 mm long |
| Triple straight | Reinforced seams: crotch, armholes, bag straps | 3 mm long |
| Blind hem | Nearly invisible hems on trousers and skirts | Width 2 to 3 mm, with the blind hem foot |
| Overcasting (overlock) | A seam finish that imitates a serger, with the overcasting foot | Preset |
Which stitches do you use in nearly every project?
The straight stitch does the seams, the hems, the topstitching and the basting. The zigzag finishes raw edges, sews elastic and rescues a seam in a stretchy fabric. The buttonhole closes shirts, skirts and cushion covers. Everything else is a specialist.
On a mechanical machine those three are a dial away. On a computerized machine they are usually the first three on the stitch chart. If a machine you are considering lacks any of the three, or has a buttonhole that needs an attachment, it is not a garment machine.
How do you set the straight stitch length?
The stitch length is the distance the feed dogs move the fabric between needle strikes, in millimeters. A 2.5 mm stitch is the standard for seams in medium-weight fabric: strong enough to hold, long enough to unpick. Lengthen to 3 or 3.5 mm on denim, canvas and thick wool so the stitches do not sink and pucker. Shorten to 1.5 to 2 mm on fine fabric and on curves, where shorter stitches follow the line more closely.
Lengthen to 4 mm or more for basting and for gathering, where you want to pull the bobbin thread. Old guides give stitch length in stitches per inch: 2.5 mm is about 10 stitches per inch, 4 mm about 6.
When do you use a zigzag stitch?
The zigzag stitch swings the needle from side to side; its width is the swing and its length the distance between swings. Its first job is finishing: a zigzag 2 to 3 mm wide and 2 mm long over the raw edge of a seam allowance stops woven fabric fraying. Its second job is anything that must stretch: sewing elastic to a waistband, a knit hem, or a narrow seam in jersey when your machine has no stretch stitch. A zigzag 1 mm wide and 2.5 mm long gives a seam that stretches a little.
A zigzag set to 0 mm wide is a straight stitch, which is why many machines use the same foot for both.
What is the three-step zigzag for?
A plain zigzag on thin or elastic fabric tends to make a ridge, because the two needle positions pull the fabric into a tunnel. The three-step (or multi-stitch) zigzag places three small straight stitches on each diagonal, so the fabric stays flat. Use it to sew elastic directly to a waist or a leg opening, on swimwear and lingerie, to finish the edge of a fine fabric, and to mend a tear. It is the stitch that earns its place on a beginner machine ahead of every decorative one.
Which stitch should you use for knit fabric?
A seam in jersey has to stretch as far as the fabric does, or the thread snaps the first time you pull the T-shirt over your head. A straight stitch cannot stretch. The stretch stitch, drawn on most dials as a lightning bolt, is a very narrow zigzag that lies almost straight and stretches with the seam. Set it 1 mm wide and 2.5 mm long and sew with a ballpoint or stretch needle.
If your machine has no stretch stitch, a plain zigzag at the same setting does the same job. For hems on knits, a twin needle gives two parallel rows on the right side and a zigzag on the wrong side that stretches. The whole approach, including a walking foot and the right needle, is in sewing knit fabrics on a regular sewing machine, and a T-shirt cut to your measurements is the project to try it on.
When is a triple straight stitch useful?
The triple straight stitch (sometimes called the stretch straight stitch) sews each stitch three times, forward, back and forward again. The result is a thick, strong line that also stretches a little. Use it on seams under strain, such as the crotch seam of trousers, the strap of a tote bag or the armholes of a close-fitting top, and for bold topstitching on denim without buying thicker thread. It is slow and hard to unpick, so keep it for seams you are sure of.
Do you need a blind hem stitch?
If you hem trousers and skirts regularly, yes. The blind hem stitch sews several straight stitches on the hem allowance and one wide zag that catches a thread or two of the garment. With the blind hem foot, which has a guide that runs against the fold, the result is almost invisible on wool and medium cottons. On fine fabrics or when the hem is on show anyway, a double-fold hem with a straight stitch is quicker. Both are explained step by step in how to hem.
One-step or four-step buttonhole?
A one-step buttonhole uses a foot that holds the button; the machine measures it and sews the two sides and the two bar tacks in one pass. A four-step buttonhole asks you to turn a dial through four positions and to judge the length yourself. Both give a usable buttonhole, but the one-step version is repeatable, which matters on a shirt with eight of them. If you are choosing a machine, the one-step buttonhole is worth paying for; the method for both is in how to sew buttonholes.
Which stitches can you ignore?
Decorative stitches, satin stitch patterns, alphabets and quilting stitches are not used in garment sewing except by choice. The overcasting stitch is pleasant with its foot but a zigzag does the same job. Preset stretch patterns beyond the lightning stitch are variations on the same idea. If a machine lists 60 stitches, you will use 6 of them in a year; the rest are a reason not to pay more.
How many stitches should a sewing machine have?
Between 12 and 20 stitches, with the straight stitch, zigzag, buttonhole, stretch stitch, three-step zigzag and blind hem among them, is enough for a lifetime of garments. What matters more is that the length and width of each are adjustable, because a stitch you cannot adjust fits only the fabric the factory had in mind. The full checklist for a first machine is in choosing a sewing machine for beginners.
When a pattern's instructions name a stitch you are not sure about, the sewing guide attached to each Sewly pattern can be asked directly ("which stitch for the side seams of this T-shirt?") and answers for your garment and fabric.