Anyone can copy a part. Proving it is the hard part.
A replacement bushing looks like the original on the photo. Whether it survives the next season depends on things you cannot see: the alloy, the heat treatment of the mating shaft, the hardness and depth of the surface layer, the fit and the clearance. That is why metal parts come with the documents agreed in the quote — 3.1 as standard, 2.2 or 3.2 on request.
Wrong material pairing
Shaft and bushing have to suit each other. The wrong bronze, or a soft steel instead of a hardened one, and the next part wears out in months — or eats the shaft.
No or wrong surface hardness
Without the specified hardness and case depth a running surface wears in weeks. Too hard and too deep, the part becomes brittle.
Fits and clearances out of tolerance
A bushing a few hundredths too tight seizes, too loose it knocks out again; a press fit that is too weak lets the bush turn in the housing.
Rough running surfaces
A shaft or sleeve that is turned but not ground destroys seals and bushes; a thin or missing chrome layer rusts through in the first season at sea.
No certificates
Without a 3.1 certificate nobody can prove what the part is made of. Superintendents and insurers will ask.
Weeks lost in transit
A cheap part that arrives late can cost a second port call. Manufacturing near the European ports shortens transit and makes dates easier to plan.
Included as standard
- Inspection certificate EN 10204 3.1 for the material of metal parts (2.2 or 3.2 on request)
- Dimensional report of the functional dimensions, fits and clearances
- Hardness report for hardened running surfaces (value and depth as agreed)
- Marking and traceability to heat or batch number
- Photo documentation before packing
When class, insurer or fleet standard ask for more
- Inspection certificate 3.2 with acceptance by a class surveyor (DNV, ABS, LR, BV, RINA, ClassNK, PRS)
- Surface roughness measurement of running and sealing surfaces
- Crack testing (magnetic particle or dye penetrant), ultrasonic testing
- Welding documentation: WPS/WPQR, welder qualification to ISO 9606-1, weld inspection report — from workshops working to ISO 3834-2
- Coating report (surface preparation, layer thickness)
- 3D model and drawing of a part reconstructed from a sample
2.2, 3.1, 3.2 — what the certificate types mean
| Type | What it confirms | Signed by | Typical use |
|---|---|---|---|
| 2.2 Test report | Results from non-specific inspection — comparable production, not your batch | Manufacturer | Non-critical parts |
| 3.1 Inspection certificate | Results of specific inspection on the delivered batch | Manufacturer's inspector, independent of production | Our standard for metal parts |
| 3.2 Inspection certificate | As 3.1, additionally witnessed | Manufacturer and the purchaser's inspector or a class surveyor | On request, e.g. class-relevant parts |
A bushing is only as good as the shaft it runs on
Wear happens in pairs. We look at the whole bearing point, not just the worn part: which material runs against which, how the shaft surface is hardened and finished, which press fit holds the bush in the housing and which running clearance the lubrication needs. If a shaft is scored, we offer a protection sleeve or a new shaft together with the bushing — so the new part does not run on an old defect.
We separate two kinds of job: normal workshop manufacture, quoted straight from your details — and parts that may be safety- or class-relevant (load-bearing, watertight, fire-rated, pressure piping). For those we clarify drawing approval, certificates, welding qualification, NDT, load proof and class acceptance before the quote. See the marking in the configurator.
What our workshops have to show
ISO 9001
Certified quality management as the minimum.
ISO 3834-2
Comprehensive quality requirements for welding; welders qualified to ISO 9606-1, welding supervision to ISO 14731.
Class approval
For welded parts going on board we prefer workshops approved by a classification society.
Calibrated gauges
Measuring and hardness testing equipment under calibration control.