The cross-hole head combines fastening with a simple tamper-evident feature. The main design considerations include:
- Wire hole design. The cross-drilled hole is sized and positioned for smooth sealing wire installation based on the application requirements.
- Simplified head profile. Removing standard drive recesses helps limit casual removal while allowing custom drive options when needed.
- Domed head shape. The rounded surface reduces snagging points and suits applications exposed to handling or outdoor conditions.
- Finished hole edges. Deburred edges help prevent damage to the sealing wire during installation and use.
- Custom threads. Thread size, length, and shank design can be adjusted to match the assembly.
The Sealing System: Screw, Wire and Seal
A lead seal screw works together with sealing wire and a seal to create a visible tamper-evident system. The screw provides the fixed attachment point, while the wire and seal record whether the assembly has been opened.
| Component | Function | Key Factors |
|---|---|---|
| Lead seal screw | Anchors the wire through the cross-hole in the head | Hole size, position, head design, material |
| Sealing wire | Connects the screw to the secured component | Material, diameter, surface protection |
| Lead seal | Locks the wire ends and provides visible evidence | Seal size, crimp mark, identification code |
The sealing process relies on plastic deformation. When the seal is crimped, the lead material forms around the wire and records the mark from the sealing tool. Any later access requires cutting the wire or breaking the seal, leaving visible evidence of removal.
The lead seal screw itself functions as a normal fastening component. The cross-hole does not increase clamping force or prevent loosening; it provides a convenient point for installing the sealing wire. Any vibration resistance should come from the screw design and thread engagement.
Sealing Sequence: Install, Route, Crimp, Verify
A lead seal is applied after the screw has been properly installed. The sealing process adds visible evidence of access without replacing the function of the fastener itself.
1.Install the screw.
Tighten the screw according to the specified assembly requirements. The seal is used for inspection purposes, not as a substitute for proper fastening.
2.Prepare the wire.
Cut the sealing wire to a suitable length, allowing enough slack for installation and movement without putting extra stress on the screw hole.
3.Route the wire.
Pass the wire through the screw cross-hole and the corresponding anchor point. Keep the wire path smooth and avoid sharp bends that may damage the wire.
4.Crimp the seal.
Insert both wire ends into the seal and crimp with sealing pliers. The crimp mark provides a visible identification record.
5.Inspect and record.
Check that the wire is securely held and record the seal information if required for traceability.
6.Removal and replacement.
When authorized access is needed, cut the wire and remove the seal. The screw can normally be reused, while the wire and seal should be replaced after opening.
Dimensions, Materials and Ordering Options
All values are typical ranges and will be confirmed according to the drawing.
| Parameter | Options |
|---|---|
| Thread | M3–M12 metric coarse; UNC/UNF available |
| Length | 8–50 mm; full or partial thread |
| Head Diameter | 6–16 mm; domed or cylindrical head |
| Cross-Hole | Ø1.5–3.0 mm; deburred edges |
| Drive | Cross-hole pin drive, slot, hex, or Torx options |
| Materials | 304/316 stainless steel, brass, carbon steel |
| Finish | Plain, polished, zinc-plated, or nickel-plated |
| Wire Compatibility | Suitable for Ø0.8–1.5 mm sealing wire |
| Quality Control | ISO 9001:2015; inspection reports and material documents available |
| Lead Time |
Typically 10–15 working days after payment |
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