Bolt Base 4 x 20 / No.8 x 3/4"
Bolt Base A2 Stainless Steel Pozi Raised Head Countersunk Wood Screws
Model: 4 x 20 / No.8 x 3/4" (30 Pack)
Product Overview
This manual provides essential information for the proper use and handling of Bolt Base A2 Stainless Steel Pozi Raised Head Countersunk Wood Screws. These screws are designed for secure fastening in wood applications, offering excellent corrosion resistance and a flush finish.

Figure 1: Bolt Base A2 Stainless Steel Pozi Raised Head Countersunk Wood Screws.
Key features include:
- Corrosion Resistant A2-70 Stainless Steel: Provides superior resistance to rust and corrosion, suitable for both indoor and outdoor applications.
- Pozi Raised Countersunk Head: Designed to sit flush with the surface of the material, providing a neat finish. The Pozi drive offers improved torque transmission and reduced cam-out compared to traditional Phillips drives.
- DIN 7995 Standard: Manufactured to meet the German Institute for Standardization (DIN) 7995 specification, ensuring quality and compatibility.
- Wood Screw Thread: Optimized thread design for strong grip and easy insertion into wood.
Specifications
| Attribute | Value |
|---|---|
| Material | A2-70 Stainless Steel |
| Standard | DIN 7995 |
| Thread Diameter | 4mm (No.8) |
| Length (Including Head) | 20mm (3/4") |
| Head Diameter | 7.5mm |
| Driver Size | PZ2 (Pozi Drive) |
| Quantity per Pack | 30 |
| Measurement System | Metric, Imperial |
Setup and Installation
Proper installation is crucial for the performance and longevity of these wood screws. Always prioritize safety during installation.
1. Safety Precautions
- Wear appropriate personal protective equipment (PPE), including safety glasses and gloves.
- Ensure your work area is well-lit and clear of obstructions.
- Use power tools according to their manufacturer's instructions.
2. Recommended Tools
- PZ2 Pozi Drive Bit: Essential for proper engagement with the screw head.
- Drill/Driver: Corded or cordless drill with adjustable torque settings.
- Pilot Drill Bit (Optional but Recommended): A drill bit slightly smaller than the screw's core diameter to create a pilot hole, especially in hardwoods or near edges, to prevent splitting.
- Countersink Bit (Optional): To create a recess for the screw head to sit perfectly flush, if desired.
3. Installation Steps
- Prepare the Material: Mark the exact location where the screw will be inserted.
- Drill Pilot Hole (Recommended): For optimal results and to prevent wood splitting, especially in dense woods, drill a pilot hole. The pilot hole diameter should be approximately 70-90% of the screw's core diameter (the part without threads). For the 4mm thread diameter, a pilot hole of 2.5mm to 3.5mm is generally suitable, depending on wood density.
- Countersink (Optional): If a perfectly flush finish is desired and the material is prone to splintering, use a countersink bit to create a conical recess for the screw head.
- Drive the Screw: Attach a PZ2 Pozi drive bit to your drill/driver. Place the screw on the bit, ensuring it is fully seated. Apply firm, steady pressure and drive the screw into the pilot hole at a moderate speed. Avoid over-tightening, which can strip the screw head or damage the wood.
- Check Tightness: The screw head should be flush with the surface of the material. If it's protruding, gently tighten further. If it's too deep, it may indicate over-tightening or an oversized pilot hole.
Operating and Usage Guidelines
These screws are specifically designed for wood applications. Adhering to these guidelines will ensure optimal performance and safety.
- Material Compatibility: Best suited for various types of wood, including softwood, hardwood, plywood, and MDF.
- Load Bearing: While strong, ensure the number and size of screws used are appropriate for the load and structural integrity required for your project. Consult engineering guidelines for critical applications.
- Environmental Conditions: A2 Stainless Steel offers good corrosion resistance, making these screws suitable for outdoor use or in environments with moderate moisture. However, for highly corrosive environments (e.g., saltwater exposure), consider A4 (316) grade stainless steel.
- Avoid Over-tightening: Excessive torque can strip the screw head, damage the Pozi recess, or cause the wood to split. Use a drill with a clutch setting to prevent this.
- Re-use: While stainless steel screws are durable, repeated removal and re-insertion into the same pilot hole can reduce holding power.
Maintenance
These stainless steel screws require minimal maintenance due to their inherent corrosion resistance. However, some considerations can prolong their aesthetic appeal and performance.
- Cleaning: If exposed to dirt or grime, clean the screw heads with a damp cloth and mild detergent. Avoid abrasive cleaners that could scratch the surface.
- Inspection: Periodically inspect screws in outdoor or high-moisture applications for any signs of surface discoloration or pitting, although rare with A2 stainless steel.
- Storage: Store unused screws in a dry environment to prevent any potential surface contamination that could lead to staining.
Troubleshooting
While straightforward to use, some common issues may arise during screw installation.
| Problem | Possible Cause | Solution |
|---|---|---|
| Screw head strips (cam-out) | Incorrect driver bit (not PZ2), worn bit, insufficient downward pressure, excessive torque. | Ensure you are using a new, correct size PZ2 bit. Apply firm, consistent downward pressure. Reduce drill speed and torque setting. |
| Wood splits when driving screw | No pilot hole, pilot hole too small, screw too close to edge. | Drill a pilot hole of appropriate size. Increase distance from edges. |
| Screw not driving fully | Pilot hole too small or absent, hitting an obstruction, insufficient power from drill. | Ensure pilot hole is correct size. Check for obstructions. Use a more powerful drill or fully charge battery. |
| Screw head not flush | Insufficient driving, no countersink, material too hard. | Drive screw further. Use a countersink bit. Ensure pilot hole is adequate for material hardness. |
Warranty and Support
For specific warranty information or technical support regarding Bolt Base products, please refer to the official Bolt Base website or contact their customer service directly. As a consumable fastening product, specific warranties may vary.
Manufacturer: Bolt Base
Date First Available: October 2, 2017
For further assistance, you may visit the Bolt Base brand page on Amazon.
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