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M21 x 20mm Aluminum 6061 Hex Cap Screw | Fastening

Expert Overview

Engineered for critical connections, this M21 x 20mm Hex Head Cap Screw is precision-machined from Aerospace Grade Aluminum 6061. Offers superior strength-to-weight ratio for lightweight yet robust assemblies.

StandardDIN 933
MaterialAluminum 6061
FinishGalvanized
GradeN/A
SizeM21
Length20mm
Head Width11mm

Detailed Engineering Specifications

Designed for demanding industrial environments, this M21 x 20mm Hex Head Cap Screw leverages the exceptional properties of Aluminum 6061, a precipitation-hardening alloy known for its moderate to high strength, excellent corrosion resistance, and good weldability. The M21 thread pitch ensures a secure and high-torque fastening solution, while the 20mm length provides ample grip for a variety of joint thicknesses. The 11mm hex head width is optimized for standard industrial tooling, facilitating efficient installation and disassembly in applications ranging from structural components in aerospace and automotive manufacturing to marine hardware and precision machinery.

🧊 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:N/A

Installation Procedure

1. Ensure mating surfaces are clean and free of debris. 2. Hand-thread the screw to engage the threads properly and prevent cross-threading. 3. Tighten the screw to the specified torque using a calibrated torque wrench, ensuring even pressure distribution.

Equivalent Standards (Cross-Reference)

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

Mechanical Properties

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

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 / ExposedExcellent
Marine / SaltwaterNot Recommended
Chemical / AcidicNot Recommended

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Over-tightening the aluminum screw, leading to thread stripping or deformation.Always use a calibrated torque wrench and adhere to recommended torque values for Aluminum 6061 fasteners to avoid damage.
Using the wrong size or type of tool on the hex head, causing cam-out and potential damage to the head.Utilize a properly fitting socket or wrench for the 11mm hex head to ensure secure engagement and prevent slippage.

Common Applications

  • Aerospace structural components
  • Automotive chassis and engine assemblies
  • Marine hardware and fittings
  • Precision machinery and tooling

⚠️ Engineering Warnings

  • Aluminum 6061 has lower tensile strength than steel; select appropriate fastener size and torque for load requirements.
  • While corrosion-resistant, avoid prolonged contact with dissimilar metals in corrosive environments without proper isolation to prevent galvanic corrosion.

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, Aluminum 6061 made from?

A: This Hex Head Cap Screw, Aluminum 6061 is manufactured from Aluminum 6061.

Q: What are the main applications?

A: Aerospace structural components, Automotive chassis and engine assemblies, Marine hardware and fittings, Precision machinery and tooling.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 20mmAF11mm1/2"-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.