Pre-Shipment Fastener Inspection: Complete Checklist for Importers

Why Pre-Shipment Inspection Exists

Once a container of fasteners leaves the port, discovering a wrong grade or a bad coating costs you the freight twice — once going and once coming back. Pre-shipment inspection (PSI) is the buyer’s last cheap chance to verify the goods, and for a technical product like fasteners it is not optional at any serious order value. This article is the checklist our customers’ third-party inspectors work from.

Documents First, Cartons Second

Before anyone opens a carton, verify the paper trail matches the goods:

Mill Test Certificate: heat numbers on the MTC must match the bundle tags in the cartons. If they don’t, the paper describes a different batch of steel.
Quantity and weight: carton count × units per carton vs the packing list; gross/net weights within tolerance.
Purchase order conformity: size, class, finish, quantity — line by line against your PO, not against what the factory “usually ships”.

Dimensional Inspection

Sample per AQL 1.0–2.5 (ANSI/ASQ Z1.4 or ISO 2859-1) and measure against the standard tables — our DIN 933 dimension chart gives the reference values for hex bolts:

Across flats (width of the hex) and head height
Body diameter and, for partial-thread bolts, thread length
Overall length — measured from under the head to the thread end, parallel to the axis
Straightness (straightedge on the shank)

Thread and Mechanical Checks

Thread gauges: a go/no-go ring gauge on bolts and plug gauge on nuts is the fastest meaningful thread check. Verify the pitch too — coarse vs fine mismatches are a classic shipping error; see our thread pitch chart.
Hardness: portable hardness testers give a quick screen; class 8.8 must fall in its Rockwell range per our strength grades guide. Failures here mean the heat treatment missed.
Proof load (nuts): a sample of hex nuts should be proof-load tested — a nut that strips at proof load is a joint that fails in service.
Coating: measure thickness with a magnetic/x-ray gauge against spec (see our zinc plating specification guide); check adhesion with a cross-hatch or bend test; look for bare spots on the galvanized parts, especially at thread runouts.

Visual and Count Checks

Head markings: grade (8.8, 10.9…) and manufacturer mark, clearly struck, correct orientation
No visible cracks, burrs, stripped threads, or flash in the threads
Surface condition: white rust on zinc, black sludge on HDG, weld spatter on anchors
Random full count of one carton per pallet — the cheapest honesty test there is

Packaging and Marking

Confirm cartons are export-grade (not collapsing under a stacked pallet), pallets are ISPM-15 heat-treated, and each carton carries your agreed label: item, size, class, finish, quantity, PO number, made-in marking. Mixed items in one carton without dividers is how a warehouse turns into an archaeological dig.

Who Does the Inspection?

Three options, in rising cost: your own QC on site, the manufacturer’s inspection report with photo/video evidence (acceptable after a supplier has proven itself), or a third-party inspection company (SGS, BV, TÜV, QIMA — typically $300–600 per man-day in China). For first orders and any order above roughly $10,000, use the third option. For a fuller supplier evaluation, pair the PSI with our manufacturer selection checklist.

Frequently Asked Questions

What AQL level should I specify for fasteners?

AQL 1.0 for critical defects (wrong grade, cracked heads, stripped threads), AQL 2.5 for major (dimension out of tolerance, coating under thickness), AQL 4.0 for minor (cosmetic marks, label offsets). Write these into the PO — “good quality” is not a specification.

Can the factory refuse a third-party inspection?

They can, and that is the result. A factory with nothing to hide treats inspection day as routine; a factory that reschedules it twice is telling you something.

How many samples should be drawn?

Follow the ISO 2859-1 sampling tables by lot size — for a typical 200-carton lot, that means a general inspection level-II sample of 125–200 pieces for dimension and visual checks, plus a small destructive sample (5–8 pcs) for hardness and, where required, tensile testing.

Do you support third-party inspection?

Yes. We ship with MTCs as standard, and every order can be inspected before loading — SGS, BV, TÜV and QIMA all work in our region. Arrange it via the enquiry form and we’ll coordinate with your inspection company.