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Galvanized Countersunk Cross Tapping Screws from Top China Suppliers | Reliable Fasteners from Quality Factory
| Thread specifications | 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 | 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 | ||
| Slot Number | 0 | 1 | 2 | 2 | 2 | 3 | 3 | 4 | 4 | |||
| M1 | Cruciform | 1.9 | 3.2 | 4.4 | 4.6 | 5.2 | 6.6 | 6.8 | 8.9 | 10 | ||
| M2 | Zigzag slot | 2 | 3 | 4.1 | 4.4 | 4.9 | 6.3 | 6.6 | 8.8 | 9.8 | ||
| y | Reference value | 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 | |||||
How to Choose a Suitable Self Tapping Screw
- 1 Select by material: Select different self tapping screws based on the material characteristics that need to be nailed in. For example, for hard materials, choose self tapping screws with high strength, appropriate length and diameter.
- 2 According to thread selection: Self tapping screws usually have two types: coarse thread and fine thread, and different threads are usually suitable for different materials.
- 3 Select according to the shape of the head: The pentagonal head self tapping screw is more sturdy than the ordinary round head self tapping screw, but the price is also relatively high.
Frequently Asked Questions (FAQ)
Q What are galvanized countersunk cross tapping screws used for?
Galvanized countersunk cross tapping screws are widely used for fastening metal sheets, wood, plastic, and other materials. The galvanized coating provides corrosion resistance, making them suitable for both indoor and outdoor applications.
Q What is the difference between coarse thread and fine thread self tapping screws?
Coarse thread self tapping screws are ideal for softer materials like wood and plastic, offering faster driving and stronger grip. Fine thread screws are better suited for harder materials such as metal, providing more precise fastening and greater holding strength.
Q How do I select the correct screw size (diameter and length)?
The screw diameter should match the thickness and hardness of the material being fastened. As a general rule, the screw length should be at least 2–3 times the thickness of the top material to ensure a secure hold. Refer to the thread specification table above for detailed dimensional data.
Q What does the galvanized coating on these screws do?
The galvanized coating applies a layer of zinc to the screw surface, which acts as a protective barrier against rust and corrosion. This significantly extends the service life of the screw, especially in humid or outdoor environments.
Q What is the advantage of a countersunk head design?
The countersunk head design allows the screw to sit flush with or below the surface of the material after installation. This creates a smooth, flat finish that is both aesthetically pleasing and functionally safer, eliminating protruding edges that could cause injury or interfere with other components.
Q What screwdriver or bit should I use for cross (Phillips) tapping screws?
Cross tapping screws require a Phillips head screwdriver or a corresponding Phillips (PH) bit for power tools. Make sure to select the correct size bit (e.g., PH0, PH1, PH2) based on the screw size to avoid stripping the head. Refer to the Slot Number column in the specifications table for guidance.