The CSK Raised Slotted Head Type AB Self-Tapping Screw is a specialized fastener integrating three core features: a countersunk (CSK) raised head (slightly protruding after installation), a straight slotted drive, and Type AB self-tapping threads. It is engineered to tap its own mating threads in pre-drilled pilot holes, eliminating the need for pre-tapped nuts or holes, and delivers a semi-low-profile finish.
• Key Design Traits: The slotted drive enables easy engagement with standard flat-blade screwdrivers; the raised countersunk head balances surface flushness and easy accessibility for installation/removal; Type AB threads (combining fine and coarse thread characteristics) offer strong gripping force in materials like plastic, wood, and thin metal sheets.
• Common Materials: Primarily made of carbon steel (for general-purpose strength) and 304 stainless steel (for corrosion resistance in humid or outdoor environments); some variants use alloy steel for heavy-duty applications.
• Surface Treatments: Typical finishes include zinc plating (for rust prevention), black oxide (for wear resistance and aesthetic appeal), and passivation (to enhance stainless steel’s anti-corrosion performance).
| THREAD | ST 2.2 | ST 2.9 | ST 3.5 | ST 4.2 | ST 4.8 | ST 5.5 | ST 6.3 | ST 8 | ST 9.5 | |
| P | 0,8 | 1,1 | 1,3 | 1,4 | 1,6 | 1,8 | 1,8 | 2,1 | 2,1 | |
| a | max. | 0,8 | 1,1 | 1,3 | 1,4 | 1,6 | 1,8 | 1,8 | 2,1 | 2,1 |
| da | max. | 2,8 | 3,5 | 4,1 | 4,9 | 5,5 | 6,3 | 7,1 | 9,2 | 10,7 |
| dk | max. | 4 | 5,6 | 7 | 8 | 9,5 | 11 | 12 | 16 | 20 |
| min. | 3,7 | 5,3 | 6,6 | 7,6 | 9,1 | 10,6 | 11,6 | 15,6 | 19,5 | |
| k | max. | 1,3 | 1,8 | 2,1 | 2,4 | 3 | 3,2 | 3,6 | 4,8 | 6 |
| min. | 1,1 | 1,6 | 1,9 | 2,2 | 2,7 | 2,9 | 3,3 | 4,5 | 5,7 | |
| n | nominal | 0,5 | 0,8 | 1 | 1,2 | 1,2 | 1,6 | 1,6 | 2 | 2,5 |
| max. | 0,7 | 1 | 1,2 | 1,51 | 1,51 | 1,91 | 1,91 | 2,31 | 2,81 | |
| min. | 0,56 | 0,86 | 1,06 | 1,26 | 1,26 | 1,66 | 1,66 | 2,06 | 2,56 | |
| r | min. | 0,1 | 0,1 | 0,1 | 0,2 | 0,2 | 0,25 | 0,25 | 0,4 | 0,4 |
| rf | approx. | 0,6 | 0,8 | 1 | 1,2 | 1,5 | 1,6 | 1,8 | 2,4 | 3 |
| t | min. | 0,5 | 0,7 | 0,8 | 1 | 1,2 | 1,3 | 1,4 | 1,9 | 2,4 |
| w | min. | 0,5 | 0,7 | 0,8 | 0,9 | 1,2 | 1,3 | 1,4 | 1,9 | 2,4 |
| y | Type C | 2 | 2,6 | 3,2 | 3,7 | 4,3 | 5 | 6 | 7,5 | 8 |
| Type F | 1,6 | 2,1 | 2,5 | 2,8 | 3,2 | 3,6 | 3,6 | 4,2 | 4,2 | |