7 16 14 double ended stud

The rubber washer plays a crucial role in this assembly. Made from durable and resilient materials, such as neoprene or silicone, it offers excellent compression and sealing properties. When tightened, the rubber washer compresses between the screw head and the surface it's fixed to, creating a waterproof and airtight seal. This is particularly beneficial in situations where leakage or environmental elements need to be kept at bay, such as in roofing, plumbing, or automotive applications.

...

Overall, countersunk head self-tapping screws are a versatile and reliable fastening solution that offers several advantages over traditional screws. Whether you are working on a DIY project at home or undertaking a professional construction project, these screws can provide the stability, security, and aesthetics you need for a successful outcome. With their ability to create clean and flush finishes, save time during installation, and withstand tough conditions, countersunk head self-tapping screws are a valuable addition to any toolbox or shop.

...

The design of an M8 wedge anchor is simple yet effective. It consists of a threaded rod with a nut and washer, accompanied by a wedge-shaped expansion sleeve. When installed, the anchor is drilled into a pre-drilled hole in the concrete, and then the bolt is inserted and tightened. As the bolt is tightened, it pulls the wedge-shaped sleeve against the sides of the hole, creating friction and causing the sleeve to expand. This expansion locks the anchor securely in place, providing a strong hold that can withstand significant loads.

...