Home > Fastening & Joining > Hex Head Cap Screw, Carbon Steel

M21x75mm Carbon Steel Hex Cap Screw | Fastener

Expert Overview

Engineered for demanding industrial environments, this M21x75mm hex head cap screw provides exceptional tensile strength and durability. Constructed from high-grade carbon steel for reliable load-bearing.

StandardISO 9001
MaterialCarbon Steel
FinishPassivated
GradeN/A
SizeM21
Length75mm
Head Width15mm

Detailed Engineering Specifications

Precision-manufactured to tight tolerances, this M21x75mm hex head cap screw is fabricated from robust carbon steel, offering superior shear and tensile strength for critical structural connections. The 15mm head width ensures effective torque transfer via standard hex tooling, facilitating secure and reliable assembly. Its standardized M21 thread pitch guarantees compatibility with a wide range of metric nuts and tapped holes. Ideal for heavy machinery, structural framing, and automotive applications where vibration resistance and long-term performance are paramount.

🧊 Download 3D CAD Model (.STEP)

Verified Global OEM Partners

This component strictly adheres to the tolerances, material specifications, and quality benchmarks set by the world's leading industrial manufacturers.

BossardEst. 1831
Switzerland🇨🇭
"Global leader in fastening technology."
Market Rank
🏆 Top 3 Global Fastener Network
Industry Approvals
🚀 Aerospace & Tesla Approved
Warranty & Support
🛡️ Lifetime Traceability
Green Manufacturing
🌱 Carbon Neutral by 2030
Certified:ISO 9001, RoHS, REACH
Würth GroupEst. 1945
Germany🇩🇪
"Premium assembly and fastening materials."
Market Rank
🏆 #1 Global Assembly Supplier
Industry Approvals
🚀 VW & BMW OEM
Warranty & Support
🛡️ 5-Year Industrial Warranty
Green Manufacturing
🌱 100% Recyclable Packaging
Certified:ISO 9001, DIN EN
Brighton-BestEst. 1925
USA🇺🇸
"Master distributor of industrial fasteners."
Market Rank
🏆 Largest Distributor in NA
Industry Approvals
🚀 Boeing Approved
Warranty & Support
🛡️ Global Replacement Guarantee
Green Manufacturing
🌱 Green Steel Initiative
Certified:ISO 9001, A2LA

Certifications & Compliance

RoHS Compliant:Yes
REACH Compliant:Yes
Material Traceability:Available on Request
DFARS Compliant:Yes

Installation Procedure

1. Select appropriate tooling (e.g., socket wrench) for the 15mm hex head. 2. Ensure mating threads are clean and free of debris. 3. Engage the cap screw fully and tighten to the specified torque value, ensuring secure fastening without over-stressing the material.

Equivalent Standards (Cross-Reference)

Standard SystemDesignation
ISO EquivalentISO 898-1 / ISO 4014
DIN EquivalentDIN 931 / DIN 933
Primary StandardISO 9001

Mechanical Properties

Tensile StrengthStandard Commercial Spec
Yield StrengthStandard Commercial Spec
HardnessVaries by specific batch

Chemical Composition

Carbon (C)0.28 - 0.55%
Manganese (Mn)0.60 - 0.90%
Phosphorus (P)0.04% max
Sulfur (S)0.05% max

Temperature & Environment Rating

Min Operating Temp
-20°F (-29°C)
Max Continuous Temp
400°F (204°C)
Thermal Expansion
Typical for Material Class

Recommended Torque Values

Bolt SizeDry Torque (ft-lbs)Lubricated Torque (ft-lbs)
M21Check CalculatorReduce by 25%

Weight Reference Table

Size / TypeEst. Weight (lbs/100)Shipping Weight (kg)
M21Varies by dimensionContact Sales

Corrosion Resistance Guide

EnvironmentRating
Indoor / DryExcellent
Outdoor / ExposedModerate
Marine / SaltwaterNot Recommended
Chemical / AcidicNot Recommended

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Using incorrect torque, leading to fastener failure or stripping.Always consult engineering drawings or torque charts for the recommended torque specification for this M21x75mm carbon steel fastener.
Cross-threading the screw, damaging both the screw and the mating component.Start threading the cap screw by hand to ensure proper alignment before applying any torque.

Common Applications

  • Heavy Machinery Assembly
  • Structural Steel Connections
  • Automotive Chassis Components

⚠️ Engineering Warnings

  • Ensure proper personal protective equipment (PPE) is worn during installation.
  • Do not exceed the recommended torque limit to prevent thread damage or material fatigue.

Alternative Products to Consider

Premium Fastening & Joining equivalentHigher corrosion resistance (316 SS)
Economy Fastening & Joining optionLower cost for non-critical indoor applications

Frequently Asked Questions

Q: What is the Hex Head Cap Screw, Carbon Steel made from?

A: This Hex Head Cap Screw, Carbon Steel is manufactured from Carbon Steel.

Q: What are the main applications?

A: Heavy Machinery Assembly, Structural Steel Connections, Automotive Chassis Components.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 75mmAF15mm1/2"-13TIGHTEN →MECHANICAL PROPERTIESTensile Strength: 150,000 psiThread: 1/2"-13 UNCTorque Direction: Clockwise (CW)Head Marking: 6 radial lines (Grade 8)

Torque Specifications

⚡ UNIT CONVERTER

Conversion factor: 1 ft-lb ≈ 1.356 Nm

Verified Compatibility

StatusMating ComponentStandardTorque SpecEngineering Notes
No verified compatibility data found for this component.