Over-tightening
Can deform caps, damage threads or make the pack difficult to open.
Torque specification
How to specify cap torque for a screw capping machine
Cap torque is one of the most important values to define when shortlisting a screw capping machine.
Buyer intent
Torque needs to be practical, measurable and matched to the cap and bottle.
Too little torque can create leaks or loose caps. Too much torque can damage threads, distort caps, make packs hard to open or create inconsistent results. A practical torque specification balances security, usability and production repeatability.
The best approach is to define an acceptable range using real bottles and caps, then test finished samples under conditions close to production.
Best-fit checks
- Define the cap and bottle combination first.
- Use a torque range, not only a single target number.
- Check opening torque as well as applied torque where relevant.
- Keep approved samples for comparison.
Specification checks
Cap torque inputs
These details help decide how the capper should be set up and checked.
| Question | Why it matters | What to send |
|---|---|---|
| Cap material | Plastic, metal and lined closures behave differently. | Cap material, liner type and closure supplier. |
| Bottle thread | Thread quality and finish affect final torque. | Bottle drawing, neck finish or sample bottle. |
| Product needs | Leaks, child resistance or tamper evidence may affect torque. | Acceptance criteria and compliance notes. |
| Operator checks | Production needs a repeatable way to verify finished caps. | Torque meter method or quality check process. |
Decision points
Torque specification risks
Under-tightening
Can cause loose caps, leaks or failed tamper evidence.
Variable samples
Cap and bottle batches can change torque behaviour, so samples matter.
Related pages
Move to the right capping route
FAQ
Capping machine questions
What torque should a screw cap have?
There is no universal value. It depends on the cap, bottle, liner, product and end-use requirement.
Can a capping machine guarantee torque?
A machine can improve repeatability, but cap and bottle consistency also affect final torque.
Should torque be tested after filling?
Yes where possible, because filled weight and product contamination can affect grip and finished quality.
What should I send with a torque enquiry?
Send samples, the desired torque range, current problems and any quality or compliance requirements.
Ready to shortlist?
Send the bottle, cap and target output.
Lancing UK will help identify the most practical capping route and quote the right machinery scope.