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M4 x 81mm 304 Stainless Steel Hex Cap Screw

Expert Overview

Engineered for robust connections, this M4 x 81mm hex cap screw boasts superior tensile strength and corrosion resistance. Ideal for critical infrastructure and demanding environments.

StandardISO 9001
Material304 Stainless Steel
FinishBlack Oxide
GradeN/A
SizeM4
Length81mm
Head Width17mm

Detailed Engineering Specifications

Purpose-built for heavy-duty applications, this M4 x 81mm hex cap screw is manufactured from premium 304 stainless steel, offering exceptional tensile strength and excellent resistance to corrosion, rust, and pitting, even in harsh chemical or marine environments. The machine thread ensures a secure, reliable fit within tapped holes or with mating nuts. Its robust hex head, with a nominal width of 17mm, provides ample surface area for torque application using standard wrenches or socket drivers, facilitating efficient assembly and disassembly of critical machinery, structural components, and high-stress equipment where consistent performance is 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. Ensure the mating threaded hole or nut is clean and free of debris. 2. Insert the M4 x 81mm hex cap screw by hand, ensuring smooth thread engagement. 3. Tighten the screw using an appropriate wrench or socket driver, applying torque gradually to the specified level for the application. Avoid 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 Strength75,000 psi (515 MPa)
Yield Strength30,000 psi (205 MPa)
Elongation in 2 in.40% min
HardnessRockwell B95 max

Chemical Composition

Carbon (C)0.08% max
Chromium (Cr)18.0 - 20.0%
Nickel (Ni)8.0 - 10.5%
Manganese (Mn)2.00% max

Temperature & Environment Rating

Min Operating Temp
-320°F (-195°C)
Max Continuous Temp
1400°F (760°C)
Thermal Expansion
Typical for Material Class

Recommended Torque Values

Bolt SizeDry Torque (ft-lbs)Lubricated Torque (ft-lbs)
M4Check CalculatorReduce by 25%

Weight Reference Table

Size / TypeEst. Weight (lbs/100)Shipping Weight (kg)
M4Varies by dimensionContact Sales

Corrosion Resistance Guide

EnvironmentRating
Indoor / DryExcellent
Outdoor / ExposedExcellent
Marine / SaltwaterGood
Chemical / AcidicNot Recommended

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Using the wrong size wrench, leading to stripped head or improper torque.Always use a wrench or socket that precisely matches the 17mm head width of the cap screw to ensure proper engagement and torque application.
Forcing the screw into a misaligned or damaged thread.Always start threading the screw by hand to confirm alignment. If resistance is met, back out the screw and inspect the threads of both the screw and the mating component before proceeding.

Common Applications

  • Structural steel connections
  • Machinery assembly and repair
  • Marine and offshore equipment

⚠️ Engineering Warnings

  • Ensure appropriate torque is applied to avoid thread stripping or component damage.
  • Verify material compatibility for the intended environment to prevent premature 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, 304 Stainless Steel made from?

A: This Hex Head Cap Screw, 304 Stainless Steel is manufactured from 304 Stainless Steel.

Q: What are the main applications?

A: Structural steel connections, Machinery assembly and repair, Marine and offshore equipment.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 81mmAF17mm1/2"-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.