What does Grade 10.9 mean for alloy steel screws?

Grade 10.9 is a metric property class designation indicating a minimum tensile strength of 1040 MPa (approximately 150,800 psi) and a proof load strength of 940 MPa. This is generally considered a high-strength fastener grade, suitable for structural, automotive, and heavy machinery applications where standard Grade 8.8 screws may be insufficient.

Can these screws be used outdoors or in corrosive environments?

Alloy steel at Grade 10.9 is generally not inherently corrosion-resistant without a surface treatment. These screws typically have a black oxide or zinc phosphate finish that provides limited corrosion protection. For outdoor or high-humidity environments, additional protection such as anti-corrosion coating or use in a protected assembly is generally recommended. Contact us to confirm the specific surface finish on your order.

What is the DIN 965 standard and what does it specify?

DIN 965 is a German industrial standard (equivalent to ISO 7046) that specifies the dimensions and tolerances for countersunk (flat head) machine screws with a cross or Torx drive. It defines head angle (typically 90°), head diameter, and thread engagement requirements. These screws are compatible with standard 90° countersunk holes in metal, wood, and composite materials.

10.9 Alloy Steel Torx Countersunk Machine Screws M3 M4 M5 M6 M8 M10 DIN 965 - HomeDIYer

Roll over image to zoom in Click on image to zoom

10.9 Alloy Steel Torx Countersunk Machine Screws M3 M4 M5 M6 M8 M10 DIN 965

HomeDIYer

No reviews

By HomeDIYer®

Thread Dia: M3

Screw Total Length: 4mm

Pack of Quantity: 1

Price:

$3.58 USD

Stock:

In stock (500 units), ready to be shipped

Quantity:

Share this product

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

DIY Expert Support

Get fitment advice & recommendations

Mon–Fri 8:30 AM – 8:00 PM

WhatsApp Email Us

24-Hour Fast Ship

Arrives in 3–14 Days

Worldwide Shipping

30-Day Returns

1 tree planted with every purchase

Grade 10.9 Torx Countersunk Screws M3–M10 — Flush-Mount Strength for Demanding Assemblies

When a standard Phillips flat head strips under torque and a hex socket leaves a protruding head where you need a flush surface, engineers and fabricators reach for Grade 10.9 Torx countersunk screws. Whether you're assembling automotive brackets, industrial equipment panels, or structural steel connections, these DIN 965 alloy steel screws deliver the clamping force and drive reliability that critical joints require.

Each screw is manufactured from Grade 10.9 alloy steel to DIN 965 specifications, featuring a 90° countersunk flat head with a six-lobe Torx (TX) drive socket. Available in thread diameters M3 through M10, with total lengths (including head) from 4mm (≈5/32") to 40mm (≈1-9/16"). Packs are available in 1, 5, 10, or 50 pieces to suit both one-off repairs and production runs.

Typical applications include automotive chassis and suspension fastening, CNC machine frame assembly, structural steel panel mounting, and industrial equipment enclosures — anywhere that Grade 10.9 Torx flat head machine screws for metal or high-strength countersunk bolts for machinery are specified.

🔩 Compatible with standard ISO metric coarse threads — fits M3, M4, M5, M6, M8, and M10 tapped holes, threaded inserts, and metric nuts per ISO 68-1. Head angle: 90° per DIN 965 / ISO 7046.

✅ Key Features of These Grade 10.9 Torx Countersunk Machine Screws

💪Grade 10.9 Alloy Steel Construction — Minimum tensile strength of 1040 MPa makes these high-strength countersunk bolts suitable for structural, automotive, and heavy machinery applications where lower-grade fasteners would fail under load.
⭐Six-Lobe Torx Drive (TX) — The Torx socket transfers torque more evenly than Phillips or slotted drives, significantly reducing cam-out risk during installation — a key advantage when using power tools on Grade 10.9 Torx flat head screws for metal.
📐90° Countersunk Flat Head (DIN 965) — The flush-mount head sits level with or below the mating surface, eliminating protrusions that could snag, interfere with mating parts, or create stress concentration points in structural assemblies.
🔧Wide Size Range in One Listing — Covers M3 through M10 diameters and lengths from 4mm to 40mm total, allowing you to source multiple sizes for a single project without managing multiple suppliers for high-strength countersunk screws.
🏭DIN 965 / ISO 7046 Dimensional Compliance — Standardized head geometry ensures compatibility with countersunk holes machined or drilled to DIN/ISO specifications, providing consistent seating depth and flush finish across assemblies.
📦Flexible Pack Quantities — Available in 1, 5, 10, or 50 pieces; larger packs reduce per-piece cost for production runs or workshop stock of alloy steel Torx countersunk machine screws.

📐 Technical Specifications — Grade 10.9 Torx Countersunk Machine Screws DIN 965

Material	Alloy steel, Grade 10.9
Head Style	Countersunk flat head, 90° angle
Drive Type	Six-lobe Torx (TX)
Standard	DIN 965 / ISO 7046
Thread Standard	ISO metric coarse (M3–M10)
Thread Diameter Range	M3, M4, M5, M6, M8, M10
Length Range (total, incl. head)	4mm (≈5/32") – 40mm (≈1-9/16")
Torx Bit Size	M3: T10 / M4: T20 / M5: T25 / M6: T30 / M8: T40 / M10: T45
Tensile Strength	≥1040 MPa (Grade 10.9)
Proof Load Strength	≥940 MPa (Grade 10.9)
Surface Finish	See variant options / Contact us to confirm
Pack Quantities	1, 5, 10, 50 pcs
Country of Origin	Contact us to confirm

⚠️ Length Note: For countersunk screws, the listed length is the total length including the head. The head sits flush with the surface when installed in a properly countersunk hole. Ensure your countersink angle matches the 90° head angle specified by DIN 965.

❓ Frequently Asked Questions

How do I choose the right length for a countersunk screw?

For countersunk (flat head) screws, the listed length is the total length including the head. The screw should be long enough so the head sits flush with or just below the surface of the material. Measure the full thickness of the material being fastened and match it to the total screw length.

Quick inch reference: 8mm ≈ 5/16", 12mm ≈ 15/32", 16mm ≈ 5/8", 20mm ≈ 25/32", 25mm ≈ 1", 30mm ≈ 1-3/16", 40mm ≈ 1-9/16".

What does Grade 10.9 mean, and how strong are these screws?

Grade 10.9 is a metric property class indicating a minimum tensile strength of 1040 MPa (approximately 150,800 psi) and a proof load of 940 MPa. This is generally considered a high-strength fastener grade — significantly stronger than the common Grade 8.8 — and is suitable for structural, automotive, and heavy machinery applications where high clamping force is required.

Can these screws be used outdoors or in wet environments?

Alloy steel at Grade 10.9 is generally not inherently corrosion-resistant without a surface treatment. These screws typically carry a black oxide or zinc phosphate finish that provides limited corrosion protection. For outdoor, marine, or high-humidity environments, additional protection or use in a sealed assembly is generally recommended. Contact us to confirm the specific surface finish on your order before use in corrosive conditions.

What is the DIN 965 standard and is it the same as ISO 7046?

DIN 965 is a German industrial standard that specifies dimensions and tolerances for countersunk (flat head) machine screws. It is functionally equivalent to ISO 7046 and specifies a 90° head angle, standardized head diameter, and thread engagement requirements. Countersunk holes machined to DIN/ISO specifications will generally accept these screws with a flush or sub-flush head seating.

What Torx bit size do I need for each thread diameter?

Torx drive sizes for these screws are typically:

M3 → T10
M4 → T20
M5 → T25
M6 → T30
M8 → T40
M10 → T45

Always verify with a test fit before applying full torque to avoid stripping the drive socket.

Are these screws compatible with standard metric tapped holes and nuts?

Yes. These screws use standard ISO metric coarse threads (M3, M4, M5, M6, M8, M10) and are compatible with standard metric nuts, threaded inserts, and tapped holes per ISO 68-1. They are not compatible with UNC/UNF inch-standard threads.

What are the typical applications for Grade 10.9 Torx countersunk screws?

Grade 10.9 Torx flat head screws are commonly used in automotive chassis and suspension assemblies, CNC machine frames, structural steel panel mounting, industrial equipment enclosures, and any application requiring a flush surface finish with high clamping force. The Torx drive is generally preferred over Phillips or hex socket in high-torque applications because it significantly reduces cam-out risk when using power tools.

🛒 Select your thread diameter, length, and quantity above, then add to cart — ships from our US warehouse.