Knurled and Screwed Vulcanized Fiber Tubes
Vulcanized fiber tubes with knurl, thread or shoulder for end termination. End terminals need grip and thread. We machine knurl, external thread or shouldered features into vulcanized fiber tubes so the cap or indicator seats and turns as designed. Feature geometry follows your terminal drawing. We check knurl and thread against the gauge before shipment. Yes. External thread and knurl are machine
Vulcanized fiber tubes with knurl, thread or shoulder for end termination. End terminals need grip and thread. We machine knurl, external thread or shouldered features into vulcanized fiber tubes so the cap or indicator seats and turns as designed. Feature geometry follows your terminal drawing. We check knurl and thread against the gauge before shipment. Yes. External thread and knurl are machine
Technical specifications
| Material | Vulcanized fiber |
| Features | Knurl / thread / shoulder |
| Use | Fuse end terminals and indicators |
| Standard | ASTM D2491 (vulcanized fiber), IEC 60269 (fuse dimensions), UL 94 V-0 (flammability, material dependent). |
| Operating temperature | -40 °C to +105 °C |
| Dielectric strength | ≥ 20 kV/mm (per ASTM test method) |
💾 Datasheets & Test Reports
Download the technical data sheet for this product (PDF).
Information required for quotation
| Base tube | Approved material grade, ID, OD, wall and conditioning as per drawing |
| Datums | Drawing datum scheme and measurement reference |
| Key dimensions | Feature positions, depths, pitch and diameters reviewed before quotation |
| Thread / profile | Standard or custom profile, class, depth, engagement and gage method |
| Other features | Holes, slots, steps, chamfers, cuts and marking |
| Acceptance | Tolerances, sampling, gages, FAI and inspection report |
| Order | Prototype and production quantity, packaging and delivery target |
Applications by industry
- Threaded and knurled fuse body ferrules and end fittings
- Mechanical insulator spacers between live busbars
- Striker/arc-rod guiding sleeves in switchgear
- Threaded standoff insulators for LV panel mounting
- Cable-entry bushings with machined threads
- Insulating grip sleeves on draw-out fuse carriers
Why vulcanized fiber for this application
When an insulating part must also fasten — threaded, knurled or keyed — vulcanized fibre holds machined features without the cracking common to brittle ceramic. It is light, cheap and sleeves cleanly onto metal ferrules for fuse bodies.
Thread depth and remaining wall are reviewed before quoting; do not run fine threads into an unmeasured thin section. Moisture conditioning required for tolerance stability.
Standards: ASTM D2491, IEC 60269-1, RoHS / REACH.
Feature and remaining-wall review
ID/OD ground or turned; CNC knurling, threading, slotting and cutting to drawing. Feature depth and remaining wall reviewed pre-quotation. Review feature depth, edge distance and remaining wall against critical geometries. Capability is confirmed on your drawing, not from a blanket tolerance.
Inspection and traceability
We state the control plan with you. Batch traceability links raw material lot to finished part.
- First-article inspection (FAI) per your plan
- In-process dimensional checks at every station
- Batch certificate of conformance (COA) supplied on request
- Lot traceability to incoming material certificate
- Dielectric strength and insulation resistance testing available on request
Related components
Custom Vulcanized Fiber Tubes
Related insulation component from the WELLELE catalog.
Medium & High Voltage Fuse Link Bodies
Related insulation component from the WELLELE catalog.
Vulcanized Fiber Washers
Related insulation component from the WELLELE catalog.
Common questions
What is the standard for vulcanized fiber tubes used in fuse assemblies?
Vulcanized fiber tubes for fuse bodies are referenced to IEC 60269 for body dimensions and end-cap geometry. Material follows ASTM D2491 (fish paper) and UL 94 V-0 for flammability. Specify the fuse link type and voltage class and we confirm the grade and tolerance.
What tolerance can you hold on vulcanized fiber tubes?
On thin-wall vulcanized fiber sections we typically hold ±0.05 mm on ID and OD. Knurl pitch, major/minor diameter and position are reviewed per drawing. Capability is confirmed against your print, not published as a blanket claim.
Is vulcanized fiber suitable for arc-facing fuse applications?
No. For arc-facing surfaces, use ceramic-filled epoxy glass, melamine or synthetic arc-quenching composites. Vulcanized fiber is for non-arc-facing mechanical bodies and end caps.
Can you supply COA and batch traceability?
Every batch is traceable to the incoming material certificate. Material COA, first-article inspection (FAI), in-process checks and final inspection reports are supplied per your plan on request.
Can you cut thread in vulcanized fiber?
Every batch is traceable to the incoming material certificate. Material COA, first-article inspection (FAI), in-process checks and final inspection reports are supplied per your plan on request.
Engineering Guides & Selection Notes
Related technical articles that help specify this product.
Get pricing for Knurled and Screwed Vulcanized Fiber Tubes
Attach the drawing with annual volume. We check the material against your duty and tolerance, verify ID / OD / wall / features, and respond with manufacturability notes and pricing.