21x25 Gauge 031021C Copper Flat Box Stitching Wire is a copper-coated low carbon steel flat wire designed for cardboard box stitching, corrugated carton closing, book binding, booklet stitching and industrial packaging. With a flat size of 0.031" x 0.021" / 0.80mm x 0.55mm, this stitching wire provides reliable stitch formation for work thickness from 1/16" to 1/2".
The 031021C stitching wire features a bright copper-coated surface, good corrosion resistance, smooth de-spooling performance and a clean flake-free finish. It is suitable for side stitching, saddle stitching and corner stitching in high-speed packaging and printing operations.
With a tensile strength range of 135,000-165,000 PSI, this flat box stitching wire balances stitch strength and machine compatibility. Proper tensile strength helps form consistent staples while reducing premature wear on stitching heads, clinchers and trimmer knives.
21x25 gauge flat stitching wire with 0.031" x 0.021" / 0.80mm x 0.55mm dimensions.
Copper-coated low carbon steel wire for bright appearance and improved corrosion resistance.
Tensile strength of 135,000-165,000 PSI for reliable stitch forming and machine compatibility.
Smooth, kink-free wire flow from the spool helps reduce downtime in high-speed stitching machines.
Clean, flake-free surface helps protect stitching heads, clinchers and trimmer knives.
559 feet per pound for efficient high-volume packaging and box stitching operations.
Recommended for work thickness from 1/16" to 1/2".
Suitable for side stitching, saddle stitching and corner stitching.
Used for cardboard boxes, corrugated cartons, books, booklets, furniture packaging, mattress packaging and machine parts packaging.
Copper coated and galvanized finishes are available for different packaging requirements.
| Specification | Details |
|---|---|
| Product Name | 21x25 Gauge 031021C Copper Flat Box Stitching Wire |
| Model | 031021C |
| Gauge | 21x25 |
| Wire Dimensions | 0.031" x 0.021" / 0.80mm x 0.55mm |
| Material | Low Carbon Steel |
| Finish | Copper Coated; Galvanized also available |
| Tensile Strength | 135,000-165,000 PSI |
| Tolerance | +/- 0.05mm |
| Feet per Pound | 559 |
| Recommended Work Thickness | 1/16" - 1/2" |
| Stitching Type | Side Stitching, Saddle Stitching, Corner Stitching |
| Main Applications | Cardboard boxes, corrugated cartons, books, booklets, furniture packaging, mattress packaging and machine parts packaging |
| Wire Gauge | Size in. | Size mm | Feet per Pound | Recommended Work Thickness |
|---|---|---|---|---|
| 18 x 20 | 0.047 x 0.035 | 1.20 x 0.90 | 221 | 5/8" - 2" |
| 19 x 21.5 | 0.041 x 0.030 | 1.05 x 0.75 | 283 | 1/2" - 1" |
| 19.5 x 21 | 0.037 x 0.031 | 0.95 x 0.80 | 283 | 1/2" - 1" |
| 20 x 24 | 0.035 x 0.023 | 0.90 x 0.60 | 408 | Up to 3/16" |
| 20 x 25 | 0.035 x 0.021 | 0.90 x 0.55 | 455 | 1/8" - 5/8" |
| 21 x 25 | 0.031 x 0.021 | 0.80 x 0.55 | 559 | 1/16" - 1/2" |
| Wire Gauge | German Wire Gauge mm | m/kg | ASWG mm | m/kg | ft/LBS | BWG mm | m/kg | ft/LBS |
|---|---|---|---|---|---|---|---|---|
| 21 | 0.8 | 253 | 0.81 | 247 | 368 | 0.81 | 247 | 368 |
| 22 | 0.75 | 288 | 0.73 | 304 | 452 | 0.71 | 322 | 479 |
| 23 | 0.65 | 331 | 0.65 | 384 | 571 | 0.63 | 409 | 609 |
| 24 | 0.6 | 451 | 0.58 | 482 | 717 | 0.56 | 517 | 769 |
| 25 | 0.55 | 536 | 0.52 | 600 | 893 | 0.51 | 624 | 929 |
| 26 | 0.5 | 649 | 0.46 | 767 | 1141 | 0.46 | 767 | 1141 |
| 27 | 0.45 | 801 | 0.44 | 838 | 1247 | 0.41 | 965 | 1436 |
| 28 | 0.4 | 1014 | 0.41 | 965 | 1436 | 0.36 | 1252 | 1863 |
| 29 | 0.37 | 1185 | 0.38 | 1123 | 1671 | 0.33 | 1489 | 2216 |
| 30 | 0.35 | 1324 | 0.36 | 1252 | 1863 | 0.3 | 1802 | 2682 |
The 031021C Copper Flat Box Stitching Wire is optimized for durable packaging, carton assembly and book stitching applications. Contact KYA Fasteners for bulk orders, wire gauge selection, finish matching, spool packing and custom specifications.
031021C copper flat stitching wire is designed for packaging and binding operations that require strong stitches, smooth wire feeding and consistent stitch formation. It is suitable for carton factories, corrugated box manufacturers, packaging plants, printing companies and industrial box stitching operations.
Stitching cardboard packaging boxes
Corrugated carton assembly and box closing
Booklet stitching and book binding
Side stitching, saddle stitching and corner stitching
Packaging furniture, mattresses and bulky goods
Securing machine parts in corrugated cartons
Industrial packaging lines and high-speed box stitching machines
Explore Related Stitching Wire
Wire tensile strength, measured in PSI, affects stitch forming, wire stiffness, machine wear and packaging reliability. The 031021C stitching wire uses a balanced tensile strength range of 135,000-165,000 PSI, helping the wire form strong stitches while remaining compatible with box stitching machines.
| Tensile Condition | Impact on Stitching Performance |
|---|---|
| Too High | Wire may be too stiff and may increase wear on stitching heads, clinchers and trimmer knives. |
| Balanced Range | 135,000-165,000 PSI supports strong stitches, smooth feeding and stable machine performance. |
| Too Low | Wire may be too soft and may fail to form consistent stitches in high-speed operation. |
| Finish | Best Use | Main Advantage |
|---|---|---|
| Copper Coated | Cardboard boxes, cartons, books, booklets and visible packaging stitches. | Bright finish, smooth feeding and clean stitch appearance. |
| Galvanized | Packaging applications requiring stronger zinc-based corrosion protection. | Improved rust resistance for selected packaging and storage environments. |
| Buyer Concern | Recommended Check |
|---|---|
| Wire Gauge | Choose 21x25 gauge for 0.031" x 0.021" / 0.80mm x 0.55mm flat wire applications. |
| Work Thickness | Match the wire size to the material thickness; 21x25 is recommended for 1/16" - 1/2" work thickness. |
| Tensile Strength | Use balanced tensile strength to avoid poor stitch forming or premature machine wear. |
| Machine Compatibility | Confirm wire size, spool type, wire feed path and stitching head requirements before bulk purchase. |
| Surface Finish | Choose copper coated wire for clean appearance and smooth feeding; choose galvanized finish when zinc-based corrosion resistance is required. |
| Spool and Packing | Confirm spool weight, carton packing, pallet packing, private-label packaging and shipping marks. |
KYA Fasteners supplies copper stitching wire, galvanized stitching wire, flat box stitching wire, book stitching wire and industrial packaging fasteners for global buyers. For corrugated carton factories, packaging plants, book binding factories, furniture packaging suppliers and machine parts packaging operations, KYA can support wire gauge selection, tensile matching, finish selection, sample testing, bulk supply and export packaging.
Factory supply for 21x25 gauge 031021C copper flat box stitching wire.
Copper coated and galvanized finish options available.
Multiple flat stitching wire sizes for different cardboard and carton thicknesses.
Balanced tensile strength for reliable stitch formation and machine compatibility.
Bulk order support for carton stitching, book stitching and industrial packaging applications.
Custom spool packing, carton labels, private-label packaging and export shipping support.
It is used for stitching cardboard boxes, corrugated cartons, books, booklets, furniture packaging, mattress packaging and machine parts packaging.
The 21x25 gauge size is 0.031" x 0.021", equal to approximately 0.80mm x 0.55mm.
Copper coated stitching wire provides a bright finish, smooth wire feeding, clean stitch appearance and practical corrosion resistance for packaging and carton stitching.
This wire uses a tensile strength range of 135,000-165,000 PSI, which helps balance stitch strength, wire flexibility and machine compatibility.
It is recommended for work thickness from 1/16" to 1/2", depending on material type, machine setting and stitch requirement.
Yes. 031021C flat stitching wire is suitable for side stitching, saddle stitching and corner stitching when matched with compatible stitching machines.
Smooth de-spooling helps reduce kinks, wire breaks, feeding interruptions and machine downtime in high-speed box stitching lines.
Yes. In addition to copper coated stitching wire, galvanized stitching wire is also available for applications that require zinc-based surface protection.
Yes. KYA can customize wire gauge, finish, tensile strength, spool packing, carton labels, private-label packaging and export packing according to buyer requirements.
