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The Range£29.28Visit shop Unifix Grade 4.8 Cup Square Hex Bolts And Nuts Din 603/555 Bright Zinc Plated - M8 X 75 (Box Of 200) - Blue
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This guide is for DIY enthusiasts and construction professionals seeking reliable fastening solutions. The Unifix Grade 4.8 Cup Square Hex Bolts and Nuts offer exceptional strength and corrosion resistance for robust assemblies. A potential caveat is their specific M8 size, requiring compatible fittings. This set includes M8 bolts and nuts, manufactured from high-quality Grade 4.8 steel, and features a Bright Zinc Plated (BZP) finish for durability.
| Colour | Silver |
|---|---|
| Model Part Number | 5014196571133 |
| Brand | Unifix |
Grade 4.8 indicates the tensile strength of the steel. '4' signifies a minimum tensile strength of 400 N/mm², and '.8' refers to the yield strength, which is 80% of the minimum tensile strength. This grade provides a good balance of strength and ductility for general use.
Yes, the Bright Zinc Plating (BZP) offers good corrosion resistance, making them suitable for many exterior applications. However, for highly corrosive environments or permanent immersion, stainless steel alternatives might be more appropriate.
Typically, for an M8 bolt, a clearance hole of around 8.4mm to 9.0mm is recommended, depending on the specific application and desired fit. Always consult project specifications or test on scrap material if unsure.
The product description states the M8 x 75 variant is supplied in a box of 40 sets, including both bolts and nuts.
Yes, as long as the replacement nuts are also M8 size and of comparable quality (e.g., Grade 4.8 or higher), they should be compatible.
The square neck under the cup head is designed to sit flush in the material and prevent the bolt from turning once it is in place. This allows you to tighten the nut securely without needing to hold the bolt head.
Check that the bolt and nut are both M8 size and that the threads are not damaged. Ensure the hole is correctly sized for the M8 bolt.
Ensure the square neck under the cup head is properly seated in the material. If the hole is too large, the neck may not engage, or consider using a washer to help seat it.
This may indicate the BZP coating has been compromised. For essential structural integrity, consider replacing the fastener. For non-critical applications, a rust inhibitor might offer temporary protection.
Setup:
Installation is straightforward. Insert the bolt through the pre-drilled holes in the materials you wish to join. Place the matching M8 nut onto the bolt thread and tighten using appropriate tools. The square neck under the cup head will seat into the material, preventing the bolt from turning while the nut is tightened.
Compatibility:
These bolts are designed for M8 fittings. Ensure that the holes you drill are appropriately sized for an M8 bolt. The accompanying nuts are also M8. They are compatible with standard M8 washers for load distribution if required.
Care:
To maintain the corrosion resistance of the Bright Zinc Plating (BZP), avoid abrasive cleaners or harsh chemicals. Clean with a damp cloth. While BZP offers good protection, prolonged exposure to highly corrosive environments (e.g., saltwater spray) may eventually degrade the finish. Store in a dry place when not in use.
