Skip to main content
Home / Connectors and Fasteners / Grade 12.9 High-Strength Countersunk Hex Socket Screws Flat Head Hex Bolts M3 M4 M5 M6 M8 M10 M20

Attributes

Brand -
Category Industrial Small Parts / Connectors and Fasteners
Origin -
Material Alloy Steel
Strength Grade 12.9
Head Style Countersunk Flat Head
Drive Type Hex Socket (Allen)
Thread Type Metric Coarse
Surface Finish Black Oxide
Standard DIN 7991
Available Sizes M3, M4, M5, M6, M8, M10, M20
Hardness 39-44 HRC
Package Quantity Varies by Selection

5 reviews

A

Anonymous

Apr 17, 2026

Rating: 5/5

Excellent Strength

Used these for high tension assembly on my CNC machine. No stripping and they held torque perfectly.

A

Anonymous

Apr 16, 2026

Rating: 5/5

High Quality

True 12.9 grade, tested with hardness kit. Very satisfied with the material quality.

A

Anonymous

Apr 02, 2026

Rating: 5/5

Fast Delivery

Arrived next day. Exactly what I needed for my automotive project. Will order again.

A

Anonymous

Mar 23, 2026

Rating: 5/5

Perfect Fit

Threads are clean and precise. M6 size fit exactly as expected without any cross-threading issues.

A

Anonymous

Mar 21, 2026

Rating: 4/5

Good Value

Great bolts for the price. Packaging could be better to prevent scratching during shipping.

5 FAQ

Q: Is this stainless steel?

A: No, this is alloy steel designed for high strength applications.

Q: Are these plated for rust resistance?

A: Yes, they feature a black oxide finish for mild corrosion protection.

Q: What key size is needed for M5?

A: You will typically need a 4mm Allen key for M5 screws.

Q: Do you sell M12 size?

A: Currently we stock up to M10 and M20. M12 is not available at this time.

Q: Is there a bulk discount available?

A: Yes, please contact support for orders exceeding 500 units.

Explore your interests

View More
All Categories
Best Seller (30)
New List (30)
Biliansheng Hair Transplant – No-Shave Technique for Eyebrows, Beard, Widow's Peak, and Sideburns; Aesthetic Design and Hair Restoration

Biliansheng Hair Transplant – No-Shave Technique for Eyebrows, Beard, Widow's Peak, and Sideburns; Aesthetic Design and Hair Restoration

$2.55

Oil Pastel Blending Stumps and Smudging Tools for Painting, Mixing, and Highlighting

Oil Pastel Blending Stumps and Smudging Tools for Painting, Mixing, and Highlighting

$4.76

Jingyangge Calligraphy Wool Felt Arm Rest Pad, Mini Felt Mat for Chinese Painting, Inkstone Protector, Creative and Exquisite Practice Mat

Jingyangge Calligraphy Wool Felt Arm Rest Pad, Mini Felt Mat for Chinese Painting, Inkstone Protector, Creative and Exquisite Practice Mat

$9.90

Concrete Mixing Plant Gantry Car Wash Platform, Shiji Runde Tunnel-Style Gantry Car Wash Machine

Concrete Mixing Plant Gantry Car Wash Platform, Shiji Runde Tunnel-Style Gantry Car Wash Machine

$20,000.00

Baohong Watercolor Paper Artist Grade 1/2/Full/Half Sheet, Student Grade 300g 100% Cotton Pulp, Rough/Medium/Fine Grain Roll

Baohong Watercolor Paper Artist Grade 1/2/Full/Half Sheet, Student Grade 300g 100% Cotton Pulp, Rough/Medium/Fine Grain Roll

$33.00

Metal Garden Bed - Large Size Vegetable Planter for Balcony and Home Gardening

Metal Garden Bed - Large Size Vegetable Planter for Balcony and Home Gardening

$1,033.00

Custom Travertine Stone Signage with Natural Marble 3D Lettering and Spherical Characters for Cafes, Clothing Stores, and Studios

Custom Travertine Stone Signage with Natural Marble 3D Lettering and Spherical Characters for Cafes, Clothing Stores, and Studios

$170.00

CANDLE.LAB | Realistic Cookie Series DIY Aromatherapy Plaster Candle Diffuser Handmade Silicone Mold

CANDLE.LAB | Realistic Cookie Series DIY Aromatherapy Plaster Candle Diffuser Handmade Silicone Mold

$12.00

Zhao Mengfu Calligraphy Copybook - Running Script 'Qingyun Zhi', Red-Traced Practice Paper for Beginners in Calligraphy

Zhao Mengfu Calligraphy Copybook - Running Script 'Qingyun Zhi', Red-Traced Practice Paper for Beginners in Calligraphy

$15.80

Aesthetic Street Scene Watercolor Line Art for Coloring, 16K Landscape Watercolor Coloring Book, Painting Book, Cotton Pulp Watercolor Album

Aesthetic Street Scene Watercolor Line Art for Coloring, 16K Landscape Watercolor Coloring Book, Painting Book, Cotton Pulp Watercolor Album

$15.80

Warehouse Nitrogen Sealing Generator - High-Purity Food-Grade PSA Skid-Mounted Container Equipment

Warehouse Nitrogen Sealing Generator - High-Purity Food-Grade PSA Skid-Mounted Container Equipment

$959.00

Ransheng UV Resin Gel, UV Crystal Glue for Gemstones, Ear Cuff Sealing, Dried Flower Molds, DIY Quick-Dry UV Epoxy

Ransheng UV Resin Gel, UV Crystal Glue for Gemstones, Ear Cuff Sealing, Dried Flower Molds, DIY Quick-Dry UV Epoxy

$44.00

Dairy Processing Production Line, Pasteurized Milk Equipment, Low-Temperature Sterilization and Fermentation Machine for Cow and Camel Milk

Dairy Processing Production Line, Pasteurized Milk Equipment, Low-Temperature Sterilization and Fermentation Machine for Cow and Camel Milk

$8,203.00

Blue Lint-Free Wiping Paper - Industrial Large Roll Oil-Absorbent Shop Towels

Blue Lint-Free Wiping Paper - Industrial Large Roll Oil-Absorbent Shop Towels

$62.00

Green-Red AB Glue 5-Minute Fast-Drying Acrylate AB Glue for Glass Ceramic Metal Structural Adhesive Quick Set

Green-Red AB Glue 5-Minute Fast-Drying Acrylate AB Glue for Glass Ceramic Metal Structural Adhesive Quick Set

$18.13

Northern Wei Dynasty Inscriptions: Twenty Pieces from Longmen [Rubbing] - Original Size Wei Bei Calligraphy Copybook from Luoyang Longmen Grottoes

Northern Wei Dynasty Inscriptions: Twenty Pieces from Longmen [Rubbing] - Original Size Wei Bei Calligraphy Copybook from Luoyang Longmen Grottoes

$40.30

Ru Kiln Celadon Ceramic Brush Washer Set - Large, Medium, and Small Ink Dishes for Chinese Calligraphy and Painting Supplies

Ru Kiln Celadon Ceramic Brush Washer Set - Large, Medium, and Small Ink Dishes for Chinese Calligraphy and Painting Supplies

$88.80

Multi-Layer Over-Toilet Storage Rack for Bathroom, Laundry Room, and Balcony - Floor Standing Organizer

Multi-Layer Over-Toilet Storage Rack for Bathroom, Laundry Room, and Balcony - Floor Standing Organizer

$44.96

Wrought Iron Solid Stainless Steel Letters – Minimalist Space Signage, Custom Metal Advertising Letters for Storefronts & Feature Walls

Wrought Iron Solid Stainless Steel Letters – Minimalist Space Signage, Custom Metal Advertising Letters for Storefronts & Feature Walls

$10.00

Shimoyama 304 Stainless Steel Telescopic Rod - Kitchen Sink Cutting Board Support Rack for Dish Drying and Cloth Hanging

Shimoyama 304 Stainless Steel Telescopic Rod - Kitchen Sink Cutting Board Support Rack for Dish Drying and Cloth Hanging

$74.80

Modified Wheel Lug Nuts Forged Steel High Strength for Lafesta Regal CT4 Civic Accord Crown Mazda3

Modified Wheel Lug Nuts Forged Steel High Strength for Lafesta Regal CT4 Civic Accord Crown Mazda3

$209.00

Milk Separator Machine - Electric Cream Skimmer and Butter Churn for Home and Commercial Use (Cow and Goat Milk)

Milk Separator Machine - Electric Cream Skimmer and Butter Churn for Home and Commercial Use (Cow and Goat Milk)

$946.00

Three-Phase Auto-Reclosing Leakage Circuit Breaker - Smart Phase Loss, Undervoltage, Overload Protection with 485 Communication for PV Grid Connection

Three-Phase Auto-Reclosing Leakage Circuit Breaker - Smart Phase Loss, Undervoltage, Overload Protection with 485 Communication for PV Grid Connection

$693.20

Multi-Function Vegetable Cutter Commercial Electric for Cafeterias Fully Automatic Chili Scallion Chopper Imitation Hand-Cut Leek Machine

Multi-Function Vegetable Cutter Commercial Electric for Cafeterias Fully Automatic Chili Scallion Chopper Imitation Hand-Cut Leek Machine

$1,600.00

Zhengtong ZT30 Fog Cannon - Micron-Level Humidification & Cooling Spray System for Steel Mills

Zhengtong ZT30 Fog Cannon - Micron-Level Humidification & Cooling Spray System for Steel Mills

$6,000.00

100Pcs Custom Clothing Hang Tags Personalized Plastic Securi

100Pcs Custom Clothing Hang Tags Personalized Plastic Securi

$125.94

Wall-Mounted Bathroom Storage Shelf, No-Drill Organizer for Sink, Shower, and Toilet Area

Wall-Mounted Bathroom Storage Shelf, No-Drill Organizer for Sink, Shower, and Toilet Area

$5.76

Thickened 5mm Wool Felt Mat for Calligraphy Practice - Premium Writing Pad for Students and Beginners, Part of Four Treasures of the Study Set

Thickened 5mm Wool Felt Mat for Calligraphy Practice - Premium Writing Pad for Students and Beginners, Part of Four Treasures of the Study Set

$2.80

Multi-Function Car Tire Stone Removal Tool with Hook for Picking Out Rocks

Multi-Function Car Tire Stone Removal Tool with Hook for Picking Out Rocks

$4.06

Label Stripping Machine – Semi-Automatic Unit for Beer, Baijiu, and Glass Bottle Label Removal; Custom Manufacturing Available

Label Stripping Machine – Semi-Automatic Unit for Beer, Baijiu, and Glass Bottle Label Removal; Custom Manufacturing Available

$19,980.00