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M21x137mm Brass Hex Head Cap Screw | Corrosion Resistant

Expert Overview

This M21x137mm Hex Head Cap Screw, crafted from premium brass, offers exceptional corrosion resistance and durability. Its robust construction ensures reliable fastening in demanding applications.

StandardDIN 933
MaterialBrass
FinishPassivated
GradeN/A
SizeM21
Length137mm
Head Width35mm

Detailed Engineering Specifications

Engineered for reliability and performance, this M21x137mm Hex Head Cap Screw boasts a substantial 35mm head width for optimal torque application and secure seating. Fabricated from high-grade brass, it exhibits excellent resistance to galvanic corrosion and chemical degradation, making it ideal for marine, chemical processing, and outdoor environments. The precisely machined threads conform to international standards, ensuring seamless integration with M21 tapped holes and nuts, providing a strong and stable mechanical joint with superior tensile and shear strength.

🧊 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. Select the appropriate mating component with an M21 internal thread. 2. Insert the cap screw through the components to be joined. 3. Tighten the cap screw using a suitable wrench applied to the 35mm hex head, ensuring the specified torque is achieved without over-tightening.

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

Chemical Composition

Copper (Cu)60.0 - 63.0%
Zinc (Zn)Balance
Lead (Pb)2.5 - 3.7%

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 excessive force leading to thread stripping or component damage.Apply the recommended torque specification for the M21 size and the materials being joined. Consult engineering drawings or torque charts.
Incorrectly matching thread pitch or diameter, leading to cross-threading.Always verify that the M21 thread size and pitch of the cap screw are compatible with the M21 tapped hole or nut before attempting installation. Hand-start the screw to check for proper engagement.

Common Applications

  • Marine hardware and fittings
  • Chemical processing equipment
  • Electrical grounding and bonding applications
  • Architectural metalwork in corrosive environments

⚠️ Engineering Warnings

  • Brass is a softer material than steel; avoid impact loads or applications requiring extreme hardness.
  • Ensure compatibility with mating materials to prevent galvanic corrosion in mixed-metal assemblies.

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, Brass made from?

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

Q: What are the main applications?

A: Marine hardware and fittings, Chemical processing equipment, Electrical grounding and bonding applications, Architectural metalwork in corrosive environments.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 137mmAF35mm1/2"-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.