In the world of construction and manufacturing, the choice of materials and components can significantly impact the overall quality and longevity of a project. Corroshield South Africa, a leading name in the industry, recently conducted a technical evaluation to compare the pull over strength of Wafer head and Countersunk head screws. The results? Intriguing and insightful for professionals and enthusiasts alike.
The Objective of the Test:
Corroshield aimed to evaluate the pull over strength of two prominent screw profiles: the Wafer head and the Countersunk head. Using concealed clips fixed with these screws, the team employed a standard pull out jig to ensure accurate and consistent results.
Dimensions Matter:
The evaluation highlighted the differences in dimensions between the two screw types:
Wafer Head Screw:
Flange Diameter: 9.31mm (Measured)
Head Height: 2.38mm (Measured)
Countersunk Head Screw:
Flange Diameter: 9.78mm (Measured)
Head Height: 4.19mm (Measured)
Interestingly, despite the Countersunk Head screw having a larger nominal head diameter and thickness, it didn’t necessarily translate to better performance.
Performance Insights:
Before the test, it was observed that the Countersunk Head Screw was not entirely flushed, leading to a floating head due to its tapered neck and higher head thickness. This observation was crucial as it played a role in the test results.
When it came to the actual pull over strength:
- Wafer Head Screw: Achieved a mean pull over load of 5,432.5N
- Countersunk Head Screw: Achieved a mean pull over load of 4,690N
This means the Wafer head profile screw showcased a superior pull over strength by a notable 15.83% (+742.5N).
Conclusions Drawn:
The evaluation led to some critical conclusions:
- Wafer head screws, despite their smaller dimensions, provide a stronger pull over strength than their Countersunk counterparts.
- The Countersunk head profile doesn’t sit flush in the pre-drilled hole of the concealed clip, leading to potential issues in practical applications.
- The use of a countersunk screw with a tapered neck can result in a floating head, increasing the risk of the fixing getting loosened.
Final Thoughts:
Corroshield South Africa’s evaluation underscores the importance of not just looking at dimensions but understanding the practical implications of component choices. As the industry continues to evolve, such insights become invaluable in making informed decisions.
Disclaimer: The insights shared in this blog post are based on the technical evaluation conducted by Engineering Edge (Pty) Ltd and provided by Corroshield South Africa. Always consult with professionals before making any decisions based on this information.
