Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D6193-16 – Standard Test Method Technical Guide
📜 Scope and Classification of Stitches and Seams
ASTM D6193-16 (Reapproved 2020) is a standard practice that covers the requirements, characteristics, category, formation, and general purpose for stitch types and seam types used in the fabrication of sewn items. This standard has been approved for use by agencies of the U.S. Department of Defense.
The standard is organized into distinct sections providing a comprehensive reference. Section 5 provides the Classification of Stitch Types for which drawings are shown in Stitch Figs. 1-69. Section 6 provides the Classification of Seam Types for which drawings are shown in Seam Figs. 70-288. Further practical guidance is offered in Annex A1, which covers Seam Assembly Recommendations.
International Standardization: This standard was developed in accordance with internationally recognized principles on standardization established by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
🧵 Critical Terminology and Bartack Specifications
The standard provides key definitions for the evaluation of sewn products. A bartack is defined as a reinforcement stitch that effectively minimizes tearing at the ends of critical stress stitchlines, including zippers, pocket flaps, and crotch/seat seams. Unlike typical seams, a bartack is specified strictly as a relationship between length, width or throw, and total stitches. It does not incorporate stitches per inch as a typical seam specification might.
The standard warns that bartacking, because of the stitch density, can exhibit severe needle-cutting, creating a self-destructive characteristic if the number of stitches is excessive, or if the sewing needle or thread size is too large for the fabric. Counting finished bartack stitches is considered virtually impossible given the three-stage process of horizontal placement, zig-zag formation, and backstitching to lock the stitches and prevent raveling.
| 🛡️ Feature | 🔷 Bartack | 🔷 Standard Seam |
|---|---|---|
| Specification Basis | Length, width/throw, and total stitches | Stitches per inch (SPI) |
| Locking Mechanism | Backstitching at both ends of the zig-zag lock | Continuous stitch formation / backtack |
| Key Risk Factor | Self-destructive needle-cutting if excess stitches or large needle/thread | General seam failure, seam grin, raveling |
⚠️ Caution on Needle Damage: The standard formally defines needle damage as “the partial or complete yarn severance or fiber fusing caused by a needle passing through a fabric during sewing.” Careful selection of needle size, thread size, and stitch density is critical in dense stitch configurations like bartacks to avoid compromising fabric integrity.
📐 Seam Assembly and Allowances
ASTM D6193 also defines the physical properties of the assembly. A seam is a line where two or more fabrics are joined, usually near the edge. The seam allowance is strictly defined as the distance from the edge of a fabric to the parallel stitch line furthest from that edge. The seam assembly is the composite structure obtained when fabric(s) are joined by means of a seam.
| 🟦 Term | 📖 Definition per D6193 |
|---|---|
| Seam | A line where two or more fabrics are joined, usually near the edge. |
| Seam Allowance | The distance from the edge of a fabric to the parallel stitch line furthest from that edge. |
| Seam Assembly | The composite structure obtained when fabric(s) are joined by means of a seam. |
| Needle Damage | The partial or complete yarn severance or fiber fusing caused by a needle passing through a fabric. |
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D6193?
This practice covers the requirements, characteristics, category, formation, and general purpose for stitch types and seam types used in the fabrication of sewn items. It includes classification schematics for stitch types (Figs. 1-69) and seam types (Figs. 70-288).
💡 How does a bartack specification differ from a standard seam specification?
A bartack is specified strictly as a relationship between its length, width/throw, and total number of stitches. It does not incorporate stitches per inch (SPI) as a typical seam specification does.
⚡ What is the primary risk associated with bartacking according to the standard?
Due to high stitch density, bartacking can exhibit severe needle-cutting, creating a self-destructive characteristic if the number of stitches is excessive, or if the sewing needle or thread size is too large for the fabric.
📌 Which ASTM document is referenced for terminology in this standard?
ASTM D123, Terminology Relating to Textiles, is the primary referenced document that provides the foundational terminology for terms used within this practice.