Vented Screws

What are vented screws?

Vented screws have a hollow core running through the centre of the fastener. This simple design allows trapped air, gas, and contaminants to escape during use, which helps prevent build-up in blind-tapped holes and makes vacuum pump-downs faster and cleaner.

They’re commonly used in high, ultra-high (UHV), and extreme ultraviolet (EUV) vacuum systems, where consistent performance is critical. Vented screws are often paired with vented washers to allow for complete outgassing and thorough surface cleaning.

What Is a virtual leak?

A virtual leak happens when gas gets trapped in a sealed space, like under a fastener in a blind hole, inside a vacuum chamber. Over time, this gas slowly seeps back into the chamber, which can contaminate the system and reduce vacuum efficiency.

By adding a vent through the screw itself, vented screws eliminate these hidden pockets of gas. This prevents unwanted outgassing and improves the overall cleanliness and performance of vacuum systems.

Why choose vented screws?

Vented screws are designed to solve problems that arise when fastening into blind holes in vacuum setups. Without venting, small spaces under the screw can trap air and particles during assembly.

As pressure drops during pump-down, that trapped air expands and escapes slowly through the threads, causing virtual leaks.