Introduction
Vented Silver Plated Bolts (SI) are purpose-built fasteners for high-vacuum (HV) and ultra-high-vacuum (UHV) assemblies where eliminating trapped volumes and ensuring consistent preload are critical. The vented shank prevents virtual leaks in blind threaded holes, while the silver plating minimizes galling and delivers repeatable torque performance—making these bolts a standard choice for CF flange connections and other critical vacuum joints.
Detailed Description
Each bolt features a longitudinal vent hole that allows trapped gases to escape during pump-down and bakeout, significantly reducing outgassing delays and pressure instability. The base material is vacuum-grade stainless steel, finished with silver plating to lower friction, resist seizure, and maintain stable clamping force through thermal cycling.
Silver plating is especially beneficial when mating stainless steel fasteners with stainless flanges and copper gaskets, as it reduces thread damage and improves reusability. These bolts are compatible with SI (inch-based) vacuum hardware commonly used on CF assemblies and are suitable for repeated assembly/disassembly in cleanroom environments.
Applications
ConFlat® (CF) HV/UHV flange assemblies
UHV chambers, beamlines, and research instruments
Semiconductor process tools and surface science systems
Thin film deposition equipment (PVD, sputtering, evaporation)
Any vacuum joint using blind tapped holes
Technical Parameters
| Parameter | Typical Value / Range | Importance |
|---|---|---|
| Thread Standard | SI (inch-based) | Compatibility with CF hardware |
| Bolt Type | Vented (through-hole) | Eliminates virtual leaks |
| Base Material | Stainless Steel | Strength & corrosion resistance |
| Surface Finish | Silver plated | Anti-galling, consistent torque |
| Head Style | Hex / Socket (size dependent) | Installation flexibility |
| Bakeout Suitability | UHV compatible | Stable under thermal cycling |
Comparison with Related Fasteners
| Fastener Type | Key Advantage | Typical Application |
|---|---|---|
| Vented Silver Plated Bolts (SI) | Venting + anti-galling | CF UHV flanges |
| Standard Stainless Bolts | Lower cost | Non-critical HV |
| Unplated Vented Bolts | Venting only | Moderate bake cycles |
| Nickel-Plated Bolts | Corrosion resistance | General vacuum use |
FAQ
| Question | Answer |
|---|---|
| Why use vented bolts in UHV systems? | They prevent gas entrapment in blind holes, reducing virtual leaks. |
| What does silver plating improve? | It lowers friction, prevents galling, and stabilizes torque/preload. |
| Are these bolts reusable? | Yes, when cleaned and inspected properly. |
| Are matching nuts and washers available? | Yes, compatible hardware can be supplied on request. |
| Can custom lengths be provided? | Yes, custom SI sizes and lengths are available. |
Packaging
Our Vented Silver Plated Bolts (SI) are cleaned for vacuum service, counted, and sealed in protective packaging to preserve plating integrity. Export-grade cartons ensure safe storage and international shipment.
Conclusion
Vented Silver Plated Bolts (SI) are essential fasteners for reliable HV/UHV assemblies, combining effective venting with superior anti-galling performance. Their vacuum-ready design ensures faster pump-down, consistent clamping, and long service life in demanding CF flange applications.
For detailed specifications and a quotation, please contact us at sales@thinfilmmaterials.com.
Dimensional Drawings
Ordering Table
| Reference | Material | Thread Size | Part Number |
| Standard Headbolts | Ag plated | #2-56 | HCHU0256-013S4PV |
| Standard Headbolts | Ag plated | #2-56 | HCHU0256-031S4PV |
| Standard Headbolts | Ag plated | #2-56 | HCHU0256-050S4PV |
| Standard Headbolts | Ag plated | #4-40 | HCHU0440-013S4PV |
| Standard Headbolts | Ag plated | #4-40 | HCHU0440-031S4PV |
| Standard Headbolts | Ag plated | #4-40 | HCHU0440-050S4PV |
| Standard Headbolts | Ag plated | #4-40 | HCHU0440-088S4PV |
| Standard Headbolts | Ag plated | #6-32 | HCHU0632-013S4PV |
| Standard Headbolts | Ag plated | #6-32 | HCHU0632-031S4PV |
| Standard Headbolts | Ag plated | #6-32 | HCHU0632-050S4PV |
| Standard Headbolts | Ag plated | #6-32 | HCHU0632-075S4PV |
| Standard Headbolts | Ag plated | #8-32 | HCHU0832-018S4PV |
| Standard Headbolts | Ag plated | #8-32 | HCHU0832-038S4PV |
| Standard Headbolts | Ag plated | #8-32 | HCHU0832-056S4PV |
| Standard Headbolts | Ag plated | #8-32 | HCHU0832-088S4PV |
| Standard Headbolts | Ag plated | #8-32 | HCHU0832-125S4PV |
| Standard Headbolts | Ag plated | #10-32 | HCHU1032-038S4PV |
| Standard Headbolts | Ag plated | #10-32 | HCHU1032-056S4PV |
| Standard Headbolts | Ag plated | #10-32 | HCHU1032-075S4PV |
| Standard Headbolts | Ag plated | #10-32 | HCHU1032-113S4PV |
| Standard Headbolts | Ag plated | #10-32 | HCHU1032-150S4PV |
| Standard Headbolts | Ag plated | 1/4-28 | HCHU2528-050S4PV |
| Standard Headbolts | Ag plated | 1/4-28 | HCHU2528-150S4PV |
| Standard Headbolts | Ag plated | 5/16-24 | HCHU3124-050S4PV |
| Standard Headbolts | Ag plated | 5/16-24 | HCHU3124-081S4PV |
| Standard Headbolts | Ag plated | 5/16-24 | HCHU3124-125S4PV |
| Standard Headbolts | Ag plated | 5/16-24 | HCHU3124-200S4PV |
| Reference | Material | Thread Size | Part Number |
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