Metric 8.8 Hex Cap Screws
Metric Class 8.8 hex cap screws are medium-strength fasteners manufactured from heat-treated medium carbon steel. They're one of the most widely used metric fasteners in industrial and OEM applications. They offer a reliable balance of tensile strength and wrenching surface across a broad size range.
Metric 8.8 hex screws are used in virtually every industrial sector for a wide range of applications, including machinery frames, structural brackets, mounting points, and other general assemblies. If a metric hex cap screw is called out on a drawing without a specific class, 8.8 is the most common default.
Empire Bolt & Screw stocks metric 8.8 hex cap screws in a range of sizes and finishes. Contact us to discuss your requirements or request a quote for bulk and OEM orders.
Metric 8.8 hex screws are used in virtually every industrial sector for a wide range of applications, including machinery frames, structural brackets, mounting points, and other general assemblies. If a metric hex cap screw is called out on a drawing without a specific class, 8.8 is the most common default.
Empire Bolt & Screw stocks metric 8.8 hex cap screws in a range of sizes and finishes. Contact us to discuss your requirements or request a quote for bulk and OEM orders.
What Are Metric 8.8 Hex Cap Screws?
A hex cap screw is a machine-threaded fastener with a six-sided head designed for installation with a wrench or socket. The hex head provides a large bearing and wrenching surface. These hex cap screws are ideal for heavy-duty and high-torque applications where socket-drive fasteners would be undersized or impractical.Metric 8.8 hex cap screws are also often used to join components in assemblies that may require frequent disassembly for maintenance or repair. They thread into tapped holes or are used with a mating nut through a clearance hole, depending on the joint design.
Hex Cap Screws vs. Hex Bolts
The terms are used interchangeably in the field, but there are real differences. Hex cap screws are cold-headed and feature a washer face on the bearing surface, a slight radius under the head, and a chamfered thread tip for clean engagement with tapped holes. They're designed to be tightened at the head. Hex bolts are typically hot-forged and intended to be assembled with a nut. Empire stocks both — the right choice depends on your joint design.Why Class 8.8?
Class 8.8 is the metric equivalent of SAE Grade 5: 800 MPa tensile strength, 580 MPa proof load. It covers the majority of general industrial fastening requirements where higher classes aren't warranted.Key Features and Benefits
- Medium-high tensile strength: 800 MPa minimum tensile strength handles demanding general industrial loads
- Heat-treated construction: Quenched and tempered for consistent mechanical properties throughout
- Reliable clamping force: 580 MPa proof load delivers stable joint preload
- Excellent wrenching surface: Six-sided head for fast installation and removal
- Serviceable by design: Used for assemblies that require periodic disassembly or maintenance
- Vibration resistance: Proper preload at Class 8.8 strength levels maintains joint integrity under dynamic loading
- Broad size availability: Stocked across a wide range of diameters and lengths
- Head identification: Marked with "8.8" on the head for quick grade verification
Common Applications for Metric 8.8 Hex Cap Screws
Class 8.8 covers a wide range of industrial fastening scenarios. Its strength-to-cost ratio makes it the default choice for general structural and mechanical assemblies that don't require the elevated strength of 10.9 or 12.9. Typical uses include:- Industrial machinery
- Manufacturing equipment
- Automotive components
- Construction equipment
- Agricultural equipment
- Conveyor and material handling systems
- Maintenance and repair operations
- OEM manufacturing
Available Materials and Finishes
Metric 8.8 hex cap screws are manufactured from medium carbon steel, heat-treated, quenched, and tempered to meet Class 8.8 mechanical requirements. Finish selection affects corrosion resistance and suitability for different environments.| Finish | Corrosion Resistance | Best For |
|---|---|---|
| Plain (no finish) | Low | Dry indoor applications, painted assemblies, or where a secondary coating will be applied |
| Zinc Plated (clear electro-zinc) | Moderate | General indoor/light outdoor use, OEM assemblies, applications with mild moisture exposure |
| Black Oxide | Low to Moderate | Indoor applications where appearance matters; minimal dimensional impact |
Choosing a finish: Plain finish is the most economical option and works well in controlled indoor environments. Zinc plating is the standard upgrade for any application exposed to moisture or outdoor elements. Black oxide provides a clean appearance with modest protection, but it's not a substitute for zinc plating in wet or corrosive environments.
If your application needs corrosion resistance beyond what a plated carbon steel fastener can provide, stainless steel metric hex cap screws are the appropriate step up.
Metric 8.8 Hex Cap Screw Dimensions & Specifications
Metric 8.8 hex cap screws are produced to DIN and ISO standards that define thread geometry, thread length, head dimensions, and mechanical properties. Key standards include:- DIN 931 / ISO 4014: Partially threaded hex cap screws with coarse thread pitch. The unthreaded shank allows for shear loading and is standard for most structural and machinery applications.
- DIN 933 / ISO 4017: Fully threaded hex cap screws. Used where full thread engagement from head to tip is needed, typically in shorter lengths or tapped-hole applications.
Why Buy Metric 8.8 Hex Cap Screws from Empire Bolt?
Empire Bolt & Screw has supplied fasteners to industrial manufacturers and OEMs since 1972. We stock Class 8.8 hex cap screws across a broad size range and can source non-standard lengths, finishes, and configurations that aren't in stock.What Sets Us Apart
- In-house Mechanical Engineer available for application support and grade selection
- Quality Assurance Laboratory with certified QC technicians
- Scheduled delivery, bulk pricing, and custom sourcing for ongoing production requirements
- Non-standard lengths and specialty finishes sourced to your specs
- VMI, Kanban, and Just-in-Time programs to keep your supply line moving
- Fast turnaround and shipping
Learn How Empire Bolt & Screw Can Be Your metric 8.8 Hex Cap Screw Supplier
Contact us to discuss your metric 8.8 hex cap screw requirements, or request a quote to get started.Looking for other hex cap screw grades? Explore our full selection, including Metric Class 10.9 Hex Cap Screws, Metric Class 12.9 Hex Cap Screws, and Stainless Steel Metric Hex Cap Screws.
