When you sew, you do not only join two pieces of fabric together. The type of seam you use decides how strong, stretchy, and neat your sewing will be. A seam type (Nahttyp) means the way fabric is joined or finished.
This guide explains the most common seam types, when to use them, machine settings, and tips to fix problems. Tables and lists make it easy to follow.
Basics: What makes a good seam?
Fabric types
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Woven fabrics (cotton, linen): strong but not stretchy → best with straight seams or flat-felled seams.
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Knits/Jersey fabrics: stretchy → need elastic seams like zigzag, overlock, or flatlock.
Stress areas
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High stress areas (shoulder, crotch): need very strong seams like flat-felled seams.
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Low stress areas (side seams of a blouse): simple seams are fine.
Machine settings
| Fabric Type | Stitch Length | Needle Type | Notes |
|---|---|---|---|
| Light fabrics | 2–2.5 mm | Microtex 70–80 | Small stitches, fine needle |
| Medium fabrics | 2.5–3 mm | Universal 80–90 | Standard settings |
| Heavy fabrics | 3.5–4 mm | Jeans 100–110 | Longer stitch for strength |
| Stretch fabrics | 2.5–3 mm | Stretch 75–90 | Use elastic stitch if possible |
Overview: Main seam types
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Straight stitch seam – the basic seam for woven fabrics
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Zigzag seam – flexible, used for stretch fabrics and finishing edges
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Overlock seam – trims, sews, and finishes in one step
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Flatlock seam – lies flat, used in sportswear
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Flat-felled seam (Kappnaht) – very strong, seen in jeans
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French seam – neat finish for fine or see-through fabrics
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Topstitching / Decorative seams – add strength and style
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Hems – different styles for fabric edges
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Bindings and piping – neat edges or decorative lines
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Tucks (Biesen) – small folds for design
Seam types explained
1. Straight stitch seam
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Use: everyday seams on woven fabrics
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Good: simple, strong
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Bad: not stretchy, not for jersey
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Setting: stitch length 2.5–3 mm
2. Zigzag seam
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Use: stretch fabrics, appliqué, buttonholes
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Types: narrow zigzag for finishing edges, wide zigzag for decoration
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Special: allows fabric to stretch
3. Overlock seam
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Use: knits, jersey, edge finishing
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Good: trims fabric, sews, and finishes edges at once
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Machine: done best with overlock machine
4. Flatlock seam
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Use: sportswear, underwear
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Good: seam is very flat, no rubbing on skin
5. Flat-felled seam (Kappnaht)
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Use: jeans, workwear, outdoor clothes
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Good: very strong, no raw edges inside
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Look: two lines of stitching visible outside
6. French seam
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Use: thin fabrics (chiffon, organza)
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Good: edges hidden inside, neat and elegant
7. Topstitching and decorative seams
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Use: jackets, bags, trousers
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Good: looks nice and also adds strength
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Tip: use twin needle for double lines
8. Hems
Types of hems:
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Simple fold hem
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Double fold hem
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Blind hem (invisible from outside)
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Coverstitch hem (stretchy, often in T-shirts)
9. Binding and piping
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Binding: edge finished with bias tape
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Piping: a small cord sewn into seam for decoration
10. Tucks (Biesen)
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Use: blouses, tablecloths, children’s clothes
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Good: small folds for shape or decoration
Read also: Dihward
Which seam for which fabric? (Quick table)
| Seam Type | Best for | Special Feature |
|---|---|---|
| Straight stitch | Cotton, linen | Standard, not stretchy |
| Zigzag | Jersey, appliqué | Elastic and flexible |
| Overlock | Jersey, sweat fabric | Cuts + sews + finishes |
| Flatlock | Sportswear | Flat and smooth |
| Flat-felled seam | Jeans, work clothes | Very strong |
| French seam | Sheer fabrics | Elegant finish inside |
| Topstitch/Decorative | Visible seams, design | Style + stability |
| Hem | All fabrics | Neat edge finish |
| Binding/Piping | Edges, cushions | Decorative and neat |
| Tucks | Blouses, linens | Folds for design |
Simple decision guide
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Woven cotton: straight stitch or flat-felled seam
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Stretchy jersey: zigzag, overlock, or flatlock
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Thin, see-through fabric: French seam
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Strong and tough areas: flat-felled seam or double stitched seam
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Decoration: topstitching, piping, tucks
Common sewing problems and fixes
| Problem | Cause | Fix |
|---|---|---|
| Fabric waves | Stitch too short, tension high | Use longer stitch, reduce tension |
| Loops of thread | Wrong bobbin tension | Check bobbin, rethread |
| Skipped stitches | Wrong or blunt needle | Use new correct needle |
| Seam breaks on stretch | Used straight stitch | Use zigzag or stretch stitch |
How to check if a seam is strong
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Stretch test: pull fabric slightly – seam should not break
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Wash test: wash a sample to see if seam holds
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Extra step: topstitching makes seams stronger
Seams in other areas (not sewing)
The word “Nahttypen” is also used in other fields:
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Welding seams: butt joints and fillet welds, used in metalwork.
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Surgical seams: stitches for closing wounds, like mattress stitch or U-stitch.
Frequently asked questions
Which seam is best for jeans?
Flat-felled seam, very strong.
What seam for jersey without overlock?
Zigzag or stretch stitch.
What stitch length for light fabric?
2–2.5 mm.
How to stop wavy seams?
Use walking foot and longer stitch.
Flatlock or overlock – what’s the difference?
Flatlock is flat, overlock trims and finishes edges.
Conclusion
There are many types of seams, each with its own use. Some are strong, some are stretchy, some are just for decoration. By choosing the right seam, your sewing becomes stronger, neater, and more fun.
Practice on scraps, test different seams, and soon you will know which one works best for each project. Sewing becomes easier when you know your seam types!
