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

For temperatures below 120°C, Nylock nuts (nylon insert) provide 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 which maintain 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: Shri Narayan Machinery LLP

Unbrako High Strength Hex Bolts and Screws are the backbone of structural and heavy-duty mechanical fastening, available in both metric Grade 10.9 (sizes M4 to M48) and inch Grade 8 (sizes 1/4" to 2"). These hex head fasteners combine the convenience of wrench-driven installation with Unbrako's premium alloy steel metallurgy, precision heat treatment, and rigorous quality control certified to ISO 9001, IATF 16949, and NABL ISO/IEC 17025. The metric range covers Property Class 10.9 with 1,040 N/mm² minimum tensile strength, while the inch range delivers Grade 8 performance at 150,000 PSI. Complemented by Unbrako Hex Nuts in ISO 4032 (Grade 8 and 10), Lock Nuts, Nylock Nuts, and All-Metal Prevailing Torque Nuts, the system provides complete hex fastening solutions from light assemblies to structural joints. Unbrako also supplies matching Spring Washers and Hardened Flat Washers. Shri Narayan Machinery LLP in Noida stocks the full Unbrako hex fastener range for industrial, automotive, and construction applications across Delhi NCR.

Request Quote Call +91-9811104037

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 entire High Strength Hex Bolts range. Contact 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) while Grade 8 uses inch threads (UNC/UNF, 1/4"-2").

Need This Product? Get a Quote Now.

Call or WhatsApp us with the model number — we'll check availability and give you the best price. Bulk orders welcome.

Call +91-9811104037 WhatsApp Us