Vented screws are used to remove trapped gases (at the bottom of blind threads) in HV (high vacuum) and UHV (ultra-high vacuum) systems. They are precision cleaned.
They are at their most effective when used with vented washers.
A blind tapped hole inside a vacuum system leaves residual air space at the bottom that cannot be fully evacuated in the vacuum cycle when a bolt, screw, or other fastener is threaded into the hole. The screw itself is a helix with a large surface area also containing voids of trapped air. This produces virtual leaks. Vented screws and fasteners ensure direct ventilation of these voids, allowing the trapped volumes of air within the threads and at the bottoms of the holes to be fully evacuated. This speeds pump-down and helps improve system performance.
In High Vacuum and Ultra High Vacuum systems, like materials can become cold-fused together (called galling) due to thermal expansion and the lack of moisture created by the vacuum. Screws threaded into blind tapped holes are commonly affected in this way, and components made of stainless steel are particularly susceptible. Finishes, coatings, and platings are uniquely formulated to prevent galling, making parts maintenance and replacement faster and easier. Without the hassle of galled, stuck fasteners, downtime is minimized.
Our vented and coated fasteners are inspected, cleaned, and packaged in a Class 100 cleanroom environment therefore particulate and organic surface contamination is significantly reduced or eliminated altogether.
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