ISO 14581 Hexalobular (Torx®) Countersunk (CSK) Head Machine Screw Datasheet
ISO 14581 Hexalobular (Torx®) CSK Head Machine Screw
ISO 14581 specifies hexalobular (Torx®) socket countersunk flat head machine screws with a 90° countersunk head and common head style. These screws provide significantly better torque transmission and reduced cam-out compared to Phillips or Pozidriv countersunk screws, making them ideal for automated assembly and high-volume manufacturing.
Unlike ISO 14582, ISO 14581 screws feature a common countersunk head with reduced loadability, making them suitable where flush mounting and reliable drive engagement are more important than maximum tensile capacity. The standard covers metric coarse threads from M2 to M10 in Product Grade A.
Table of Contents
ITEM CODE: 1046
| Standard | Status |
|---|---|
| ISO 14581 | Primary Standard |
| EN ISO 14581 | Equivalent |
| DIN EN ISO 14581 | German Adoption |
| BS EN ISO 14581 | British Adoption |
Dimensions
| d1 | M2 | M2.5 | M3 | M4 | M5 | M6 | M8 |
|---|---|---|---|---|---|---|---|
| d2 | 3.8 | 4.7 | 5.5 | 8.4 | 9.3 | 11.3 | 15.8 |
| k | 1.2 | 1.5 | 1.65 | 2.7 | 2.7 | 3.3 | 4.65 |
| t | 0.64 | 0.79 | 0.83 | 1.53 | 1.51 | 1.78 | 2.54 |
| A | 1.75 | 2.4 | 2.8 | 3.95 | 4.5 | 5.6 | 7.95 |
| Drive | T6 | T8 | T10 | T20 | T25 | T30 | T45 |
all dimensions in mm
Dimensions Tolerances:
General dimensional tolerances for standard metric fasteners—including thread diameter, overall length, head diameter, head height/thickness, across flats, and washer dimensions—are available in our Standard Dimensional Tolerances for Common Metric Fasteners guide.
Certain product-specific features, such as drive recess dimensions, socket depth, countersink geometry, under-head radii, and other special characteristics, are governed by the applicable DIN or ISO product standard and may not included in this datasheet.
Download Technical Datasheets
Stainless Steel
| Grade | Download |
|---|---|
| A2-70 (SS304) | ⬇️ Download Datasheet |
| A4-70 (SS316) | ⬇️ Download Datasheet |
Mechanical Properties
| Material / Property Class | Tensile Strength | Yield Strength | Standard |
|---|---|---|---|
| Steel 4.8 | ≥ 400 MPa | ≥ 320 MPa | ISO 898-1 |
| Steel 5.8 | ≥ 500 MPa | ≥ 400 MPa | ISO 898-1 |
| Steel 8.8 | ≥ 800 MPa | ≥ 640 MPa | ISO 898-1 |
| Stainless Steel A2-50 | ≥ 500 MPa | — | ISO 3506-1 |
| Stainless Steel A2-70 | ≥ 700 MPa | ≥ 450 MPa | ISO 3506-1 |
| Stainless Steel A4-70 | ≥ 700 MPa | ≥ 450 MPa | ISO 3506-1 |
| Titanium Grade 2 | Approx. 345 MPa | Approx. 275 MPa | ASTM B348 |
| Titanium Grade 5 | Approx. 895 MPa | Approx. 828 MPa | ASTM B348 |
Material Characteristics and Recommended Applications
| Material | Characteristics | Typical Applications |
|---|---|---|
| Steel Class 4.8 | General-purpose fastening | Electrical assemblies, furniture |
| Steel Class 8.8 | Higher tensile strength | Industrial machinery |
| Stainless Steel A2 (304) | Excellent corrosion resistance | Food processing, HVAC, electrical panels |
| Stainless Steel A4 (316) | Superior corrosion resistance | Marine, offshore, chemical plants |
| Brass | Non-magnetic, decorative, conductive | Electrical equipment, instrumentation |
| Titanium Grade 2 | Lightweight, corrosion resistant | Aerospace, medical equipment |
| Titanium Grade 5 | High strength-to-weight ratio | Aerospace, motorsports, high-performance engineering |
Technical Specifications
| Property | Specification |
|---|---|
| Standard | ISO 14581 |
| Screw Type | Machine Screw |
| Head Style | Countersunk Flat Head |
| Head Angle | 90° |
| Drive Type | Hexalobular (Torx®) |
| Thread | ISO Metric Coarse |
| Thread Direction | Right Hand |
| Product Grade | Grade A |
| Standard Size Range | M2 – M8 |
| Materials | Stainless Steel, Carbon Steel, Alloy Steel, Titanium |
| Finish Options | Plain, Zinc Plated, Yellow Zinc, Black Oxide, Geomet®, Dacromet®, Passivated Stainless |
| Installation | Flush Mounting |
| Assembly Tool | Torx Driver Bit |
ISO 14581 CSK Torx Head Screw Weight Chart
Weight in kgs. per 1,000 pcs. All weights are approximations.
| Diameter/ Length | M2 | M2.5 | M3 | M4 | M5 | M6 | M8 |
|---|---|---|---|---|---|---|---|
| 3 | 0.101 | 0.175 | |||||
| 4 | 0.119 | 0.206 | 0.29 | ||||
| 5 | 0.137 | 0.236 | 0.335 | 0.676 | |||
| 6 | 0.152 | 0.266 | 0.379 | 0.754 | 1.21 | ||
| 8 | 0.193 | 0.326 | 0.467 | 0.91 | 1.45 | 2.19 | |
| 10 | 0.231 | 0.386 | 0.555 | 1.06 | 1.7 | 2.54 | 5.03 |
| 12 | 0.268 | 0.446 | 0.643 | 1.22 | 1.95 | 2.89 | 5.67 |
| 14 | 0.306 | 0.507 | 0.731 | 1.37 | 2.19 | 3.25 | 6.3 |
| 16 | 0.343 | 0.567 | 0.82 | 1.53 | 2.44 | 3.6 | 6.94 |
| 18 | 0.381 | 0.627 | 0.908 | 1.68 | 2.69 | 3.95 | 7.57 |
| 20 | 0.417 | 0.687 | 0.996 | 1.84 | 2.94 | 4.31 | 8.21 |
| 22 | 0.747 | 1.08 | 1.99 | 3.18 | 4.66 | 8.84 | |
| 25 | 0.838 | 1.22 | 2.22 | 3.55 | 5.19 | 9.79 | |
| 28 | 1.35 | 2.46 | 3.93 | 5.72 | 10.7 | ||
| 30 | 1.44 | 2.61 | 4.16 | 6.08 | 11.4 | ||
| 35 | 3 | 4.65 | 6.96 | 13 | |||
| 40 | 3.38 | 5.4 | 7.84 | 14.6 | |||
| 45 | 6.02 | 8.73 | 16.2 | ||||
| 50 | 17.8 | ||||||
| 55 | 19.4 | ||||||
| 60 |
Applications
ISO 14581 CSK Torx Screws are commonly used in:
- Electrical control panels
- Electronics enclosures
- Telecommunications equipment
- Data centre hardware
- Robotics
- Medical equipment
- Precision instruments
- Industrial automation
- Consumer electronics
- Automotive interiors
- Aerospace assemblies
- Machine guards
- Sheet metal fabrication
Advantages
- Excellent torque transmission
- Superior resistance to cam-out
- Suitable for automated assembly
- Flush installation in countersunk holes
- Better tool engagement than Phillips or Pozidriv
- Reduced recess wear
- Improved assembly consistency
- Available in corrosion-resistant materials
- Clean, professional appearance
- Widely used in electronics and precision engineering
Frequently Asked Questions
What is ISO 14581?
ISO 14581 specifies hexalobular (Torx®) socket countersunk flat head machine screws with a common head design intended for flush mounting applications.
What is the difference between ISO 14581 and ISO 14582?
ISO 14581 has a common-height countersunk head with reduced loadability, whereas ISO 14582 uses a high countersunk head that provides full tensile loadability. They are not interchangeable because the head dimensions differ.
Why choose Torx instead of Phillips?
The Torx drive provides higher torque transfer, minimizes cam-out, reduces driver wear, and is better suited to automated assembly.
What sizes are covered by ISO 14581?
The ISO standard covers M2 through M10 metric coarse thread screws.
What materials are commonly available?
Carbon steel, alloy steel, stainless steel (A2, A4), titanium.
Are stainless steel versions available?
Yes. Common grades include A2-70 and A4-70, with A4 recommended for marine and corrosive environments.
What industries commonly use ISO 14581 screws?
Automotive, electronics, telecommunications, industrial machinery, robotics, aerospace, medical equipment, and electrical manufacturing.
Need Technical Assistance or a Quote?
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- Standard Dimensional Tolerances
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