🔧 M4–M16 External Hex Slotted Machine Screws – A2 Stainless Steel, High Strength & Corrosion Resistant
You’re bolting down a heavy machine guard, assembling outdoor equipment, or repairing a piece of industrial gear – and you need a screw that you can torque properly with a wrench. These external hex slotted screws give you the best of both worlds: a full hex head for a spanner or socket, plus a straight slot for a flathead screwdriver. Made from A2 stainless steel (304), they resist rust, heat, and oxidation – perfect for outdoor, marine, and factory environments. Available in diameters from M4 up to M16, with a range of lengths (select from dropdown). Fully threaded for maximum grip. Use them where high torque and corrosion resistance are required.
✨ Key Features – External Hex Slotted Machine Screws
- 🔩 External hex head with slotted drive – Use a standard wrench, socket, or flathead screwdriver. No special bits needed.
- 🛡️ A2 stainless steel (304) – Excellent corrosion resistance, oxidation resistance, and heat resistance. High strength and toughness.
- 🔧 High torque capability – Hex head allows you to apply significantly more torque than a Phillips or slotted alone.
- 📏 Wide metric range M4 to M16 – From small electronics enclosures up to heavy machinery and structural mounts.
- 📐 Fully threaded, coarse pitch – Threads run the entire length under the head. Maximum grip in blind holes or with nuts.
- ⚙️ Versatile use – Industrial equipment, outdoor structures, marine hardware, automotive repairs, and general construction.
📏 Specifications – External Hex Slotted Screws (A2 Stainless Steel)
| Thread Diameter (M) |
Thread Pitch (mm) |
Typical Length Range (mm) * |
Head Style |
Drive |
Material |
| M4 |
0.7 |
Lengths vary by diameter – typical range from 8mm up to 150mm. Select exact size from dropdown. |
External hexagon (hex head) |
Slotted (flathead) + hex wrench |
A2 304 Stainless Steel |
| M5 |
0.8 |
| M6 |
1.0 |
| M8 |
1.25 |
| M10 |
1.5 |
| M12 |
1.75 |
| M14 |
2.0 |
| M16 |
2.0 |
* Length measured from underside of head to tip (grip length). All screws are fully threaded. Hex width across flats follows standard metric dimensions (e.g., M4 → 7mm, M5 → 8mm, M6 → 10mm, etc.).
📋 Why A2 Stainless Steel for Hex Slotted Screws?
| Property |
Benefit |
| Corrosion resistance |
Excellent – resists rust in outdoor, humid, and coastal environments. No need for plating. |
| Strength |
High tensile strength (A2‑70 ~700 MPa). Withstands heavy loads and vibration. |
| Heat & oxidation resistance |
Suitable for high‑temperature applications (e.g., exhaust manifolds, industrial ovens). |
| Dual drive convenience |
Slotted recess for quick hand start; hex head for final torque with a wrench. |
❓ Frequently Asked Questions – External Hex Slotted Screws
1. What tools can I use to drive these screws?
You have two options: a standard flathead screwdriver (for the slotted recess) or a wrench / socket (for the external hex head). For high torque, always use the hex head to avoid damaging the slot.
2. Are these screws fully threaded? What about very long lengths?
Yes – all screws in this range are fully threaded from under the head to the tip. This gives you maximum thread engagement regardless of the material thickness.
3. Can I use these screws outdoors? Will they rust?
A2 stainless steel (304) is highly corrosion‑resistant and perfect for outdoor use – rain, humidity, and even coastal air. For continuous saltwater immersion, consider A4 (316) stainless, but for most general outdoor applications, A2 is excellent and will not rust.
4. What size wrench do I need for each screw?
Standard metric hex head dimensions: M4 uses 7mm, M5 uses 8mm, M6 uses 10mm, M8 uses 13mm, M10 uses 16mm, M12 uses 18mm, M14 uses 21mm, M16 uses 24mm. Always use the correct size to avoid rounding the corners.
5. Can I use these screws with a nut? What size nut fits?
Yes – these are machine screws. Use standard metric hex nuts of the same thread size and pitch (e.g., M8 nut for an M8 screw). For outdoor applications, pair with stainless steel nuts to avoid galvanic corrosion.
6. Do you offer these screws in other materials like carbon steel or brass?
This listing is for A2 stainless steel. We also carry carbon steel and brass versions in our store – please check other listings or contact us for custom orders.
