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M21x139mm Brass Hex Cap Screw | Fastener Experts

Expert Overview

This M21x139mm brass hex head cap screw offers excellent corrosion resistance and non-magnetic properties. It is precisely engineered for secure fastening in demanding environments, ensuring reliable performance and a clean aesthetic.

StandardISO 9001
MaterialBrass
FinishPlain
GradeN/A
SizeM21
Length139mm
Head Width31mm

Detailed Engineering Specifications

Precision-manufactured to tight tolerances, this M21x139mm hex head cap screw is constructed from high-grade brass (e.g., UNS C36000), providing superior corrosion resistance to saltwater, chemicals, and atmospheric conditions. The hexagonal head, with a nominal width of 31mm, allows for high torque application via standard wrenches and sockets. Its M21 metric thread ensures a robust and secure connection in a variety of substrates. The inherent non-magnetic properties of brass make it ideal for applications where magnetic interference is a concern, such as in electrical components and sensitive equipment.

🧊 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 threads are clean and free of debris. 2. Hand-thread the screw to confirm proper engagement and alignment. 3. Tighten the screw using an appropriate wrench or socket to the recommended torque specification, avoiding over-tightening.

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

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 material deformation.Consult torque charts for brass fasteners or use a calibrated torque wrench to achieve the correct tension without damaging the components.
Mating brass screws with incompatible materials that can cause galvanic corrosion.When joining dissimilar metals, consider isolating the brass fastener with non-conductive washers or coatings to mitigate galvanic corrosion risks.

Common Applications

  • Electrical conductivity components
  • Marine hardware and fittings
  • Decorative and architectural elements
  • Corrosion-resistant assemblies

⚠️ Engineering Warnings

  • Brass can deform under excessive impact or stress; handle with care.
  • While corrosion-resistant, prolonged exposure to certain aggressive chemicals may affect brass integrity.

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: Electrical conductivity components, Marine hardware and fittings, Decorative and architectural elements, Corrosion-resistant assemblies.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 139mmAF31mm1/2"-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.