SS Self Tapping Screw CSK Head
Stainless steel countersunk head self-tapping screws to ISO 7050 that form their own thread in pre-drilled holes. The 80° flat head sits flush with the surface. Available in A2 (304) and A4 (316) grades, sizes ST2.2 to ST6.3, Form C or Form F points.
Specification
#
Standard
ISO 7050 (supersedes DIN 7982); equivalent to DIN EN ISO 7050
Thread
Coarse (standard)
Material
Stainless Steel 304 (A2)
Grade
A2-70
Stock
In stock (304). Grade 316 available against bulk order
Surface Finish
Plain/passivated (standard for stainless steel)
Head Type
Countersunk (flat head), 80-degree included angle
Drive Type
Phillips (H), Pozidriv (Z), Hexalobular/Torx (IRS)
Point Form
Form C (cone/gimlet point) or Form F (flat/blunt end)
Dimension
#
Size (d mm)
Thread Dia (min-max mm)
Pitch
Length (mm)
Thread Length (mm)
ST2.9
2.9-2.9
1.1
13
13
ST3.5
3.5-3.5
1.3
16
16
ST4.2
4.2-4.2
1.4
19
19
ST4.8
4.8-4.8
1.6
22
22
ST5.5
5.5-5.5
1.8
25
25
- All dimensions in mm, tolerance +/- 0.01 mm. Additional dimensions available on request.
Benefits
#
Countersunk self-tapping screws eliminate two manufacturing steps by forming threads directly in pre-drilled holes without separate tapping operations, while the flush head removes the need for secondary finishing to address protruding fasteners. The 80° countersunk head seats level with the material surface, preventing snagging and creating a smooth finish that meets hygiene requirements in food processing and pharmaceutical environments. Stainless steel construction provides corrosion resistance without coatings, reducing lifecycle maintenance costs. The self-tapping thread cuts into sheet metal, plastics, and composites, creating a secure mechanical connection in thin substrates where through-bolting is impractical. Available with Phillips, Pozidriv, or hexalobular drives, these screws adapt to hand assembly or automated production lines. Engineers select countersunk self-tappers when flush mounting, corrosion resistance, and reduced assembly time are simultaneous requirements in thin-gauge fabrication.
Common Applications
#
CSK head self-tapping screws are used in thin-gauge assemblies where a flush surface and corrosion resistance are required:
- Sheet metal fabrication and enclosure assembly
- HVAC ductwork and ventilation systems
- Electrical panel and control box assembly
- Automotive body panels and interior trim
- Marine fittings and deck hardware
- Architectural cladding and facade panels
- Appliance manufacturing and assembly
- Food processing and pharmaceutical equipment
- Solar panel mounting and framing
- Signage and display fixture assembly
Read Me
| Standard | ISO 7050 (supersedes DIN 7982); equivalent to DIN EN ISO 7050 |
| Thread | Coarse (standard) |
| Material | Stainless Steel 304 (A2) |
| Grade | A2-70 |
| Stock | In stock (304). Grade 316 available against bulk order |
| Surface Finish | Plain/passivated (standard for stainless steel) |
| Head Type | Countersunk (flat head), 80-degree included angle |
| Drive Type | Phillips (H), Pozidriv (Z), Hexalobular/Torx (IRS) |
| Point Form | Form C (cone/gimlet point) or Form F (flat/blunt end) |
| Size (d mm) | Thread Dia (min-max mm) | Pitch | Length (mm) | Thread Length (mm) |
|---|---|---|---|---|
| ST2.9 | 2.9-2.9 | 1.1 | 13 | 13 |
| ST3.5 | 3.5-3.5 | 1.3 | 16 | 16 |
| ST4.2 | 4.2-4.2 | 1.4 | 19 | 19 |
| ST4.8 | 4.8-4.8 | 1.6 | 22 | 22 |
| ST5.5 | 5.5-5.5 | 1.8 | 25 | 25 |
