Should I use a lock nut or Nylock nut with Unbrako hex bolts?

For temperatures below 120°C, Nylock nuts (nylon insert) give effective vibration resistance at low cost. For temperatures above 120°C or severe vibration, use All-Metal Prevailing Torque Nuts. For the highest vibration resistance, consider Unbrako Durlok self-locking fasteners — they hold full preload under the most extreme conditions.

Where can I buy Unbrako hex bolts and nuts in Noida?

Shri Narayan Machinery LLP in Sector 9, Noida stocks the complete Unbrako hex fastener range including bolts, nuts, lock nuts, and washers in metric and inch sizes. Call +91-9811104037 for availability and bulk quotations.

Unbrako

High Strength Hex Bolts & Screws: Unbrako Grade 10.9 / Grade 8

Name: High Strength Hex Bolts & Screws: Unbrako Grade 10.9 / Grade 8
Brand: Unbrako

Grade 10.9 metric or Grade 8 inch, same strength, different threads: Unbrako high strength hex bolts deliver 1,040 N/mm² (about 150,000 PSI) minimum tensile strength across M4 to M48 and 1/4" to 2", in partial and full thread versions to ISO 4014/4017 and DIN 931/933. It's a complete system, not just bolts: ISO 4032 hex nuts in Grade 8 and 10, Nylock nuts for vibration below 120°C, all-metal prevailing torque nuts above that, plus spring and hardened flat washers. Manufacturing is ISO 9001 and IATF 16949 certified with NABL-accredited testing and E-Code lot traceability. Structural fabricators, machinery builders, and automotive plants across Noida-NCR buy these by the box or by the tonne. Stocked at Sector 9, Noida; WhatsApp size and grade for price.

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Available — pickup today from Sector 9, Noida

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Property Class (Metric): 10.9Grade (Inch): Grade 8 (SAE J429)Min. Tensile Strength (Metric 10.9): 1,040 N/mm² (150,800 PSI)Min. Tensile Strength (Inch Gr.8): 150,000 PSI

Key Features

Grade 10.9 metric, 1,040 N/mm² minimum tensile strength

Grade 8 inch, 150,000 PSI minimum tensile strength

Premium alloy steel with controlled heat treatment for uniform hardness

Hex head for standard wrench or socket wrench installation

Complete system: hex bolts, hex nuts (Grade 8/10), lock nuts, nylock nuts, washers

ISO 9001, IATF 16949, ISO 14001, ISO 45001 certified manufacturing

NABL ISO/IEC 17025 accredited testing laboratory

E-Code lot traceability on all Unbrako hex fasteners

Available in metric M4-M48 and inch 1/4"-2"

Special coatings available: Hot Dip Galvanizing, Geomet, Delta Protekt

Technical Specifications

Property Class (Metric)	10.9
Grade (Inch)	Grade 8 (SAE J429)
Min. Tensile Strength (Metric 10.9)	1,040 N/mm² (150,800 PSI)
Min. Tensile Strength (Inch Gr.8)	150,000 PSI
Min. Yield Strength (Metric 10.9)	940 N/mm²
Material	Alloy Steel, Quenched & Tempered
Finish	Black Oxide (standard), Hot Dip Galvanized, Geomet, Delta Protekt on request
Metric Size Range	M4, M5, M6, M8, M10, M12, M14, M16, M18, M20, M22, M24, M27, M30, M33, M36, M39, M42, M45, M48
Inch Size Range	1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 3/4", 7/8", 1", 1-1/8", 1-1/4", 1-3/8", 1-1/2", 1-3/4", 2"
Nut Grades Available	Grade 8 (ISO 4032), Grade 10 (ISO 4032), Nylock, All-Metal Prevailing Torque
Washer Types Available	Spring Washers (square/flat section), Hardened Flat Washers

Applications

The High Strength Hex Bolts is used across a wide range of industrial applications:

Structural steelwork, beam-to-column connections, bracing, base plates
Heavy machinery, frame assemblies, motor mounting, gearbox housing bolting
Automotive chassis, suspension mounts, subframe bolting, engine cradles
Flanged pipe connections, complementing studbolts in non-critical joints
Material handling equipment, crane assemblies, hoist frames, conveyor structures
Agricultural machinery, plough assemblies, harvester frames, implement mounting
Power generation, turbine housing, generator base frames, transformer mounting
General mechanical assembly, any application requiring high-strength wrench-driven fastening

Industries Served

Heavy Engineering & Steel FabricationAutomotive & Commercial VehiclesConstruction & InfrastructurePower GenerationAgricultural EquipmentMaterial HandlingOil & GasGeneral Engineering

Need High Strength Hex Bolts? Get the Best Dealer Price

As your Unbrako dealer, Shri Narayan Machinery LLP offers competitive pricing on the full High Strength Hex Bolts range. Call us for availability and your best quote.

Request Quote on WhatsApp Call +91-9811104037

C-101, Sector 9, Noida, Uttar Pradesh 201301 | Unbrako Dealer

Frequently Asked Questions: High Strength Hex Bolts

Grade 10.9 is the metric designation and Grade 8 is the inch (SAE) designation. Both indicate high-strength alloy steel fasteners with similar tensile strength (approximately 150,000 PSI / 1,040 N/mm²). The key difference is the thread system: Grade 10.9 uses metric threads (M4-M48) and Grade 8 uses inch threads (UNC/UNF, 1/4"-2").

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