Stainless Steel Socket Head Cap Machine Screws Hex Socket Drive Metric M3 M4 M5 For Industrial Assembly
What is a socket head cap machine screw?
It is a machine screw with a cylindrical head and a hexagonal recess (socket) in the top. You drive it with an Allen key or hex driver. The hex socket is recessed into the head, so the tool does not protrude. This makes it perfect for applications where clearance is tight.
Why choose socket head over other head styles?
| Feature | Benefit |
|---|---|
| Recessed hex drive | Tool does not protrude – works in tight spaces |
| Six-point contact | Distributes torque evenly – less stripping |
| Cylindrical head | Smaller diameter than hex head – fits narrow recesses |
| High torque capacity | Can be tightened more than Phillips or slotted |
| Clean appearance | Smooth cylindrical head looks professional |
Common applications
- Machinery assembly and maintenance
- Automotive components and engines
- Industrial equipment frames
- Mold and die construction
- Robotics and automation
- Medical devices
- Marine hardware
- Electronics enclosures (low profile versions)
Head styles within socket head family
| Type | Best for |
|---|---|
| Standard socket head | General purpose, most common |
| Low profile socket head | Height restricted areas |
| Button head socket | Decorative, lower profile, lighter load |
| Flat head socket | Countersunk, flush mounting |
Drive specifications
| Drive type | Tool required | Torque capacity |
|---|---|---|
| Hex socket | Allen key / hex driver | High |
| Torx socket | Torx driver | Very high |
| Phillips | Phillips screwdriver | Moderate |
| Slotted | Flat blade | Low |
Material options
| Material | Best for |
|---|---|
| 304 stainless steel | General corrosion protection |
| 316 stainless steel | Marine, saltwater, chemicals |
| Alloy steel | High strength, heat treated |
| Carbon steel | Cost effective, with plating |
| Brass | Non-magnetic, decorative |
Strength grades
| Grade | Tensile strength | Use case |
|---|---|---|
| Class 8.8 | 800 MPa | General industrial |
| Class 10.9 | 1000 MPa | Higher load |
| Class 12.9 | 1200 MPa | Maximum strength |
Surface finishes
| Finish | Best for |
|---|---|
| Plain | Standard, cost effective |
| Zinc plated | Mild corrosion protection |
| Black oxide | Matte finish, indoor use |
| Passivated | Stainless steel, maximum corrosion resistance |
| Nickel plated | Decorative, good corrosion resistance |
Sizes available
Metric M2, M2.5, M3, M4, M5, M6, M8, M10, M12. Lengths from 4mm to 100mm. Standard and fine thread options. Inch sizes also available.
Quality
ISO 9001 and ISO 10012 certified. Every batch inspected. Dimensional accuracy, thread gauging, hardness testing.
Custom
Need a non-standard size, special material, or unique head marking? Send us your drawing. We manufacture to your specification. OEM orders accepted.
FAQ
Socket head has a recessed hex drive inside the head. Hex head has external six sides you grip with a wrench. Socket head works in tighter spaces because the tool goes inside the head.
An Allen key or hex driver. The size matches the socket diameter, not the head diameter.
Socket heads handle higher torque without stripping. Phillips drive cams out when torque gets high. Socket heads also work better in automated assembly.
Alloy steel Class 12.9 is the strongest. It is heat treated for maximum tensile strength.
Yes. Choose 304 or 316 stainless steel for corrosion resistance. 316 is better for saltwater environments.
The head height is reduced. Useful when vertical clearance is limited.
Yes. Send us your drawing or sample. We make exactly what you need.
About YH Fastener
YH Fastener has been manufacturing precision fasteners since 1998. Our range includes socket head cap machine screws, self tapping screws, shoulder screws, and custom fasteners. ISO 9001 and ISO 10012 certified. Every batch inspected. Factory direct. Ship to 60+ countries.
- Recessed hex socket drive – tool fits inside the head
- High torque capacity – no cam out, no stripping
- Cylindrical head – fits tight spaces
- Standard, low profile, button, and flat head styles
- 304 SS, 316 SS, alloy steel Class 12.9
- Metric M2 to M12, Class 8.8 to 12.9
