Mechanical belt fastener check
Is the fastener rated for your belt tension, thickness and the smallest pulley it passes over?
Result
How it works
Mechanical fasteners are quick to fit, but each size has a maximum working tension, a minimum pulley diameter and a belt-thickness range. A fastener too small for the pulleys causes cuts and cracks next to the splice and early failure.
Enter the values from the fastener maker’s catalogue for the exact size. The page compares them with your belt tension, belt thickness and the smallest pulley the splice passes over — including snub and bend pulleys.
Formula
Working tension per width = T1 × 1000 / B [N/mm] Working tension ≤ fastener rated working tension Smallest pulley ≥ fastener minimum pulley diameter Fastener min thickness ≤ belt thickness ≤ fastener max thickness
| Symbol | Meaning | Unit |
|---|---|---|
| T1 | Maximum belt tension | kN |
| B | Belt width | mm |
| rating | Fastener rated working tension (catalogue) | N/mm |
Worked example
Inputs: Fastener rated working tension = 70 N/mm; Belt maximum tension T1 = 34.3 kN; Belt width = 1000 mm; …or working tension per width = N/mm; Fastener minimum pulley diameter = 400 mm; Smallest pulley the splice passes = 315 mm; Belt thickness = 12 mm; Fastener minimum belt thickness = 8 mm; Fastener maximum belt thickness = 14 mm; Belt speed = 2.3 m/s; Fastener maximum speed (if stated) = m/s.
- Working tension = 34.3 × 1000 / 1000 = 34.3 N/mm ≤ 70 → OK
- Smallest pulley 315 mm < fastener minimum 400 mm → not suitable
- Belt 12 mm within 8–14 mm → OK
- Choose a fastener rated for 315 mm pulleys, a larger pulley, or a vulcanised splice (all fastener values here are illustrations)
Assumptions and limits
- All limits come from the fastener maker’s catalogue for the exact fastener size. This page contains no fastener table.
- Some catalogues rate fasteners in PIW (working tension): 1 PIW = 0.1751 N/mm — use the splice unit converter.
- Use the smallest pulley the splice passes over, measured over the lagging.
Screening estimate, not a design approval. Verify measured inputs, current standards, manufacturer limits and site procedures before purchasing, cutting or installation. Isolate and lock out equipment before any hands-on measurement.
Questions
Why does pulley size matter for fasteners?
Fastener plates are rigid. Round a small pulley they lever against the belt, cutting and cracking it next to the splice.
Can I use a fastener on a steel cord belt?
Only where the fastener maker specifically rates it for that belt; most heavy steel cord belts need a vulcanised splice.
Source notes
- Cuts at mechanical splices from fasteners too small for the pulley: Mercurio Manual of Conveyor Belts and Splices REV.08/22 p.69. Unit errors in a fastener catalogue noted in the splicing source review. No catalogue data reproduced.
Related calculators
More: Belt roll length · Conveyor belt length · Belt sag · Drive traction (T1/T2) · Pulley speed (rpm) · Conveyor capacity · Te & belt tensions · Splice length · Splice dew point · Press & edge iron · Steel cord splice · Idler load & impact · Transition length · Vertical curve radius · Motor & gearbox check · Drive power · Belt cover wear · Cover grade checklist · Spare reorder point
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