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HANDAN HAOSHENG FASTENER CO., LTD.

DIN 7991 Hexagon Socket Countersunk Head Screws

DIN 7991 Hexagon Socket Countersunk Head Screws

Our DIN 7991 Hexagon Socket Countersunk Head Screws (also known as flat head socket cap screws) are precision-engineered fasteners designed to sit completely flush with or below the workpiece surface. Featuring a flat 90° countersunk head and an internal hexagon socket drive, these screws provide a smooth, snag-free finish while delivering high clamping force through efficient torque transmission .

Manufactured in strict compliance with DIN 7991 (equivalent to ISO 10642) standards, these screws are ideal for applications requiring aesthetic appearance, space clearance, or safety from protruding heads

  • Description

Product Details


Name

Hexagon Socket Countersunk Head Screws

Materials

Carbon Steel/Stainless Steel

Standards

DIN7991/ISO10642

Strength level

4.8 8.8 10.9 12.9 A2-70 A4-70 A4-80 

Size

M3-M24

Surface finish

ZP/YZP/Black/Teflon/HDG/Dacromet

Length

6-200

Samples

Available


Product Parameters


Screw ThreadM3M4M5M6M8M10M12(M14)M16(M18)M20(M22)M24
d
PPitch0.50.70.811.251.51.75222.52.52.53
αtol.(+2)90°90°90°90°90°90°90°90°90°90°90°60°60°
bL≤12512141618222630343842465054
125<L ≤ 200///24283236404448525660
L>200/////4549535761656973
dkmax=nominal size681012162024273033363639
min5.77.649.6411.5715.5719.4823.4826.4829.4832.3835.3835.3838.38
dsmax=nominal size345681012141618202224
min2.863.824.825.827.789.7811.7313.7315.7317.7319.6721.6723.67
emin2.32.873.444.585.726.869.1511.4311.4313.7213.721616
kmax1.72.32.83.34.45.56.577.588.513.114
sNominal Size22.534568101012121414
min2.022.523.024.025.026.028.02510.02510.02512.03212.03214.03214.032
max2.12.63.14.125.146.148.17510.17510.17512.21212.21214.21214.212
tmax=nominal size1.21.82.32.53.54.44.64.85.35.55.98.810.3
min0.951.552.052.253.24.14.34.555.25.68.449.87


Key Features & Benefits


Flush-Mount Design: The 90° countersunk head sits level with the workpiece surface after installation, eliminating snag hazards and enabling smooth mating of assembled parts 

High Torque Transmission: Internal hexagon socket drive allows for superior torque transfer compared to slotted or Phillips drives, reducing cam-out and driver wear 

Multiple Material Grades: Available in carbon steel (Grades 8.8, 10.9, 12.9) and stainless steel (304/A2-70, 316/A4-80) for diverse application requirements 

Corrosion Resistant Finishes: Zinc plated (blue, white, yellow), hot-dip galvanized, black oxide, Dacromet, or plain stainless steel for various environmental conditions 

Full Thread Coverage: Fully threaded design ensures maximum thread engagement and holding power throughout the entire screw length 

DIN 7991 / ISO 10642 Compliance: Manufactured to strict dimensional standards ensuring interchangeability and consistent quality worldwide


Intended Applications


Industrial & Machinery: Equipment assembly, machine tooling, conveyor systems, and security guarding 

Automotive: Interior components, engine accessories, chassis assemblies 

Construction & Architecture: Curtain wall installation, aluminum framing, metal cladding, and facade systems 

Electronics & Enclosures: Server racks, control cabinets, instrument housings, and electronic device assembly 

Marine & Offshore: Boat deck fittings, offshore platform components, coastal infrastructure 

Medical Equipment: Surgical instruments, diagnostic devices, laboratory equipment (A4 stainless recommended) 

Furniture & Joinery: Metal furniture assembly, decorative hardware, and concealed fastening applications 


Installation Guidelines


1.Prepare Countersink Hole: For optimal flush seating, the workpiece requires a 90° countersink matching the screw head angle

2.Select Correct Tool: Use the appropriate metric hex key (Allen wrench) that fits snugly into the socket drive to prevent stripping 

3.Avoid Over-Torque: Due to the head geometry, these screws have lower load-bearing capacity than standard cap screws. Follow torque specifications for the grade and size 

4.Use Anti-Seize for Stainless: Apply lubricant or anti-seize compound when installing stainless steel screws to prevent thread galling

5.Check Flushness: After installation, the head should sit flush with or slightly below the workpiece surface


Why Choose Our DIN 7991 Countersunk Screws?


Standards Compliant: Full compliance with DIN 7991 and ISO 10642 specifications

Comprehensive Range: All standard metric sizes from M3 to M24 in stock

Multiple Materials: Carbon steel (8.8-12.9) and stainless steel (304/316) available

Quality Assurance: Rigorous dimensional and mechanical testing; material certifications (EN 10204 3.1) available upon request

Bulk & Retail Quantities: Suitable for both small projects and large industrial orders

Technical Support: Expert guidance on grade selection, torque values, and application engineering


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