This M21x125mm Hex Head Cap Screw, constructed from robust carbon steel, offers exceptional tensile strength and durability. Its precise dimensions and reliable performance make it a cornerstone for critical structural and mechanical assembly.
| Standard | DIN 933 |
| Material | Carbon Steel |
| Finish | Passivated |
| Grade | N/A |
| Size | M21 |
| Length | 125mm |
| Head Width | 31mm |
Trusted by engineers across multiple sectors, this M21x125mm Hex Head Cap Screw is engineered from high-grade carbon steel, providing superior tensile strength and resistance to shear forces. The M21 thread size ensures robust engagement, while the 125mm length facilitates substantial grip in thicker materials. Its 31mm hex head width allows for high torque application using standard tooling, crucial for maintaining pre-load integrity in heavy machinery, structural frameworks, and automotive applications where reliability is paramount.
This component strictly adheres to the tolerances, material specifications, and quality benchmarks set by the world's leading industrial manufacturers.
1. Ensure the mating threads are clean and free from damage. 2. Hand-thread the cap screw to confirm proper alignment and prevent cross-threading. 3. Tighten the cap screw to the specified torque using an appropriate wrench or torque multiplier.
| Standard System | Designation |
|---|---|
| ISO Equivalent | ISO 898-1 / ISO 4014 |
| DIN Equivalent | DIN 931 / DIN 933 |
| Primary Standard | DIN 933 |
| Tensile Strength | Standard Commercial Spec |
| Yield Strength | Standard Commercial Spec |
| Hardness | Varies by specific batch |
| Carbon (C) | 0.28 - 0.55% |
| Manganese (Mn) | 0.60 - 0.90% |
| Phosphorus (P) | 0.04% max |
| Sulfur (S) | 0.05% max |
| Bolt Size | Dry Torque (ft-lbs) | Lubricated Torque (ft-lbs) |
|---|---|---|
| M21 | Check Calculator | Reduce by 25% |
| Size / Type | Est. Weight (lbs/100) | Shipping Weight (kg) |
|---|---|---|
| M21 | Varies by dimension | Contact Sales |
| Environment | Rating |
|---|---|
| Indoor / Dry | Excellent |
| Outdoor / Exposed | Moderate |
| Marine / Saltwater | Not Recommended |
| Chemical / Acidic | Not Recommended |
| ❌ Mistake | ✅ Correct Approach |
|---|---|
| Over-tightening the cap screw, leading to thread stripping or component deformation. | Always adhere to the recommended torque specifications for the material and application. Utilize a calibrated torque wrench. |
| Using the wrong size wrench, which can round the hex head and impede proper tightening or removal. | Select a wrench that precisely fits the 31mm hex head to ensure maximum surface contact and prevent slippage. |
A: This Hex Head Cap Screw, Carbon Steel is manufactured from Carbon Steel.
A: Heavy machinery assembly, Structural steel connections, Automotive chassis and powertrain.
Conversion factor: 1 ft-lb ≈ 1.356 Nm
| Status | Mating Component | Standard | Torque Spec | Engineering Notes |
|---|---|---|---|---|
| No verified compatibility data found for this component. | ||||