Product Specifications
| Model / Specification | ST2.2 - ST9.5 |
| Material | Carbon Steel |
| Thread d |
ST2.2 | ST2.9 | ST3.5 | ST4.2 | ST4.8 | ST5.5 | ST6.3 | ST8 | ST9.5 | ||
| P | Pitch | 0.8 | 1.1 | 1.3 | 1.4 | 1.6 | 1.8 | 1.8 | 2.1 | 2.1 | |
| a | Max. | 1.6 | 2.2 | 2.6 | 2.8 | 3.2 | 3.6 | 3.6 | 4.2 | 4.2 | |
| dk | Theor. | Max. | 4.4 | 6.3 | 8.2 | 9.4 | 10.4 | 11.5 | 12.6 | 17.3 | 20 |
| Act. | Max. | 3.8 | 5.5 | 7.3 | 8.4 | 9.3 | 10.3 | 11.3 | 15.8 | 18.3 | |
| Min. | 3.5 | 5.2 | 6.9 | 8 | 8.9 | 9.9 | 10.9 | 15.4 | 17.8 | ||
| k | Max. | 1.1 | 1.7 | 2.35 | 2.6 | 2.8 | 3 | 3.15 | 4.65 | 5.25 | |
| Recess No. | 0 | 1 | 2 | 2 | 2 | 3 | 3 | 4 | 4 | ||
| M1 | Type H | Ref. | 1.9 | 3.2 | 4.4 | 4.6 | 5.2 | 6.6 | 6.8 | 8.9 | 10 |
| Depth | Type H | Max. | 1.2 | 2.1 | 2.4 | 2.6 | 3.2 | 3.3 | 3.5 | 4.6 | 5.7 |
| Min. | 0.9 | 1.7 | 1.9 | 2.1 | 2.7 | 2.8 | 3 | 4 | 5.1 | ||
| M2 | Type Z | Ref. | 2 | 3 | 4.1 | 4.4 | 4.9 | 6.3 | 6.6 | 8.8 | 9.8 |
| Depth | Type Z | Max. | 1.2 | 2.01 | 2.2 | 2.51 | 3.05 | 3.18 | 3.45 | 4.6 | 5.64 |
| Min. | 0.95 | 1.76 | 1.75 | 2.06 | 2.6 | 2.73 | 3 | 4.15 | 5.19 | ||
| y | Ref. | 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 | ||
| Type R | - | - | 2.7 | 3.2 | 3.6 | 4.3 | 5 | 6.3 | - | ||
Cross Recessed Countersunk Head Tapping Screw — Product Introduction
The cross recessed countersunk head tapping screw is a self-tapping fastener with a countersunk (flat) head and a cross recess drive. Its conical head surface mates with the countersunk hole in the connected part; after tightening, the screw head can sink completely into the base material surface, achieving a flush and neat connection. The product is manufactured according to GB/T 846-2017, with thread specifications covering ST2.2–ST9.5. It is mainly used for fastening connections between thin metal sheets, plastics and wood materials, without pre-tapping, relying on its own thread to extrude a mating internal thread in the pilot hole.
1. Product Features
• Countersunk flush design: The head has a 90° conical countersunk surface. After tightening, it is flush with the base material surface, suitable for applications with high appearance requirements or where the screw head must not protrude.
• Cross recess drive: Uses standard cross recess (PH1, PH2, etc.), compatible with common Phillips screwdrivers or power tools, providing stable torque transmission and reducing slippage.
• Self-tapping thread structure: The pitch is larger than ordinary machine screws, and the pointed design facilitates quick penetration into the base material, extruding a mating thread without pre-tapping.
• Wide specification coverage: According to GB/T 846-2017, thread specifications cover ST2.2–ST9.5, product grade A.
• Various materials and surface treatments: Common materials include carbon steel (such as SWRCH22A, 1022) and stainless steel (304/316). Carbon steel parts can be blue-white zinc plated, nickel plated, etc.; stainless steel parts are usually supplied in natural or bright-washed condition.
2. Product Advantages
• Flat surface after installation: The countersunk structure embeds the screw head into the base material, improving appearance neatness and avoiding scratch risks.
• Single-side operation and high efficiency: No mating nut or back-side work is required, suitable for closed structures or assembly scenarios accessible from one side.
• Eliminates tapping process: The self-tapping thread is directly extruded, simplifying the assembly process and suitable for automated production lines and batch use.
• Suitable for various base materials: Can be used for wood, plastic, thin metal sheets (thickness ≤2 mm), etc., with flexible application.
3. Scope of Application
• Furniture manufacturing and assembly: Panel connections for wardrobes, cabinets, tables and chairs, and other wooden or panel furniture.
• Building decoration and renovation: Fixing of gypsum board ceilings, partition keels, skirting lines and decorative panels.
• Electronics and home appliances: Assembly of housings and internal components of small appliances, electronic equipment chassis and lighting fixtures.
• Outdoor and bathroom facilities: Stainless steel versions can adapt to humid environments such as outdoor furniture, awnings and bathroom cabinets.
• General industrial assembly: Thin sheet connection applications requiring quick fastening, such as light mechanical equipment, automotive interior parts and communication equipment chassis.
