Mechanical Coupling Specification Example for Long-Haul Trucks: Fixed Type
Mechanical Coupling Specification Example for Long-Haul Trucks: Fixed Type
This is a worked specification for mechanical coupling in a fixed type programme. It is the document we would send a buyer who asks what exactly they are getting: the material, the dimensions that are actually controlled, the finish, and the checks that happen before anything is packed.
The fixed type version exists because the duty cycle on long-haul trucks is not the same as on a showroom vehicle. Where the two are specified identically, something fails later — usually lead time that slipped twice before bulk started.

Example specification
| Item | Mechanical Coupling |
|---|---|
| Application | Long-Haul Trucks |
| Version | Fixed Type |
| Base material | Titanium Alloy |
| Controlled dimensions | 6 key dimensions, recorded per lot |
| Tolerance band | ±0.5 mm |
| Finish | as machined |
| MOQ | 500 pieces per specification |
| Sampling | 14 working days, 5 days per revision |
| Compliance | ISO 9001 |
How the example is built up
- Start from the duty cycle, not from the catalogue photograph.
- Fix the base material in writing — Titanium Alloy, in this example.
- List the dimensions that are actually controlled and the tolerance on each.
- Name the finish and what it has to survive.
- State the inspection level and who pays when a lot fails.

Processes involved
- powder coating
- ultrasonic cleaning
- heat treatment
- surface grinding
- assembly line testing
- precision stamping
Where this example applies
Programmes that run fixed type most often specify this build for long-haul trucks. Related applications include utility trailers, long-haul trucks, camper conversions, scooter fleets, emergency vehicles.
Checks before packing
- Dimensional report against the approved drawing.
- AQL 1.5 sampling on the finished lot.
- Finish inspection under agreed lighting.
- Carton drop test on the first lot of a new packing specification.
Questions buyers ask
What happens if a lot fails inspection?
The lot is re-inspected against the golden sample, and replacement pieces ship on the next available booking at our cost.
How is packing specified?
Individual packing, inner box quantity and carton marking are confirmed at quotation stage so the cartons arrive ready for your warehouse.
Can you match an existing sample?
Send a sample and we will reverse-engineer the specification, then produce a counter sample for approval before any bulk starts.
How long does sampling take?
Samples leave the factory in 14 working days, and each revision round adds about 5 days once you have seen the first piece.
Share a sample or a drawing and we will quote against a written specification, not against a photograph.



