BUYER KNOWLEDGE / T.K. EXCELLENT · 14 OCTOBER 2026
Start with the joint, not a bigger number
When a connection loosens, increasing torque or choosing a higher property class is not automatically the right answer. The joint may be losing preload through settlement, movement or an unsuitable assembly process. Investigation should identify the mechanism before changing the specification.
Nord-Lock's published wedge-locking principle is a useful example of a designed securing method. Its paired washers use cam geometry to resist rotational loosening. That product-specific principle should not be treated as a claim that every washer prevents loosening or that washer selection replaces joint design.
What ISO 16047 contributes
ISO 16047:2005 specifies conditions for torque/clamp-force testing of threaded fasteners and related parts within a defined scope. The official abstract identifies applicable materials and thread ranges and exclusions, including screws that form their own mating thread and fasteners with additional self-locking features. Buyers should check the actual scope before naming the standard in an order.
A plastic wall plug and screw installation, for example, cannot be approved simply by borrowing a bolt-tightening value. The substrate, hole, plug geometry, matching screw and installation method introduce a different set of questions.
Make the test request reproducible
| Information | Why it matters |
|---|---|
| Exact fastener and mating component | Defines the tested combination |
| Finish and specified lubrication condition | Controls an important source of friction variation |
| Test procedure and equipment | Allows results to be interpreted consistently |
| Measured quantities and acceptance limits | Separates a torque reading from the required outcome |
| Sample and batch identity | Connects results to the supplied product |
Changing a finish while keeping a torque instruction unchanged deserves review. Even a change that improves corrosion protection can affect assembly behaviour. The correct response is to validate the defined combination, not to assume the former instruction transfers unchanged.
Read the result with its limitations
Ask for the distribution of results and the test conditions, not just a single favourable value. A successful laboratory result establishes what was tested under those conditions. It does not automatically prove fatigue performance, vibration resistance or suitability for an unrelated application.
Can I use a generic torque chart?
It can support preliminary discussion where appropriate, but the final instruction should be approved for the actual joint and application requirements.
Does a locking feature guarantee permanent preload?
No universal guarantee follows from the presence of a feature. Design, installation and service conditions remain important, and product instructions must be followed.
For a T.K. Excellent enquiry, provide the drawing, mating materials, finish and required validation. This creates a clearer technical discussion than a request for a bolt that is simply “stronger” or “tighter”.
Bring a clear brief to your next sourcing discussion
Share your application, product or drawing, destination market, quantity and packing requirements.
Discuss this topic with WeiWei Yang · Contact T.K. Excellent
Sources and further reading
Prepared by the T.K. Excellent Editorial Team. Sources checked on 14 October 2026. Practical checklists are editorial guidance; product suitability, test requirements and commercial terms must be agreed for the specific project.
Manufacturing, anchor ODM and retail packaging · More technical guides