CONSTRUCTION
MACHINERY

CIVILEQUIP BUYING GUIDE

First samples, lot checks and material records: what to ask a machinery parts supplier for

Separate first-sample approval from lot inspection, decide which tests travel with each shipment, and agree a sampling plan before the first order.

By · Updated

Two different approvals

A good first sample shows the supplier can make the part once. The next thousand need their own check. Treat the order as two approvals: first-sample approval, where every drawing requirement is checked on a small number of parts, and lot acceptance, where an agreed sample from each delivery is checked against a shorter list of critical features.

Drawing-led suppliers already work this way. Muyang describes a sample route before production, and the Henao and JW Casting profiles separate casting approval from finished-part acceptance. Process equipment has the same split: a Miaoliang cleaning trial on your dirty parts is the first sample, and the cleanliness check written into acceptance is the lot test.

What the first sample should come with

Ask for a full dimensional report against the current drawing revision, the material identity and the heat or batch it came from, and the result of any test that defines the part's function. For wear parts, that means hardness and, where specified, microstructure; the FIORM M60E tooth page and the Lingfeng profile both recommend a controlled material trial before a repeat order. For seals, the trial is in the gland: QuanSeaL spring-energised seals should be validated with your groove, medium and pressure, not only from the style table.

For equipment, the first sample is a trial run. Ask what material was used and what result was measured: a powder trial for a valve-bag packer, a feed test for a vacuum belt filter, or a force-displacement curve for a servo press.

Lot records for fasteners and wear parts

Fasteners are where lot records are most often missing. ISO 898-1 sets mechanical and physical properties for bolts, screws and studs by property class, tested at room temperature; a class marking is a claim that the lot meets those values. Ask for the lot number on the box, the test results for that lot, and the matching nut lot when bolt and nut are sold as a joint.

The Weishun track-shoe bolt page asks for bolt and nut lot records together. The Yiteng and Yuhe profiles show why old certificates are not enough: documents that predate the current company, or name another entity, do not describe a new batch such as a 4F3665 plow bolt. Jetty also lists cutting-edge bolts alongside wear parts, so ask which items it makes and which it buys in. More on joint geometry is in our guide to teeth, adapters and plow bolts.

Agree the sampling plan before the order

Lot acceptance needs a written plan: which characteristics, how many parts per lot, and how many nonconforming parts are allowed. ISO 2859-1:2026 is the common reference for inspection by attributes; it indexes sampling schemes by acceptance quality limit (AQL) and adds skip-lot procedures in this edition. You do not need to buy the standard to agree the essentials: name the AQL and inspection level for critical and minor defects, and state that the supplier keeps the records for each lot.

Write the plan into the purchase order, and attach the drawing revision it applies to. When a part such as a Muyang casting bracket moves from sample to series, the same plan becomes the basis for every later delivery in ground-engaging tools or any other category.

Sources

  1. ISO 2859-1:2026 Sampling procedures for inspection by attributes
    AQL-indexed sampling schemes for lot-by-lot inspection; third edition adds skip-lot procedures.
  2. ISO 898-1:2013 Mechanical properties of fasteners — bolts, screws and studs
    Property-class requirements tested at 10–35 °C; confirmed current in 2025.
  3. ISO 8062-3:2023 Tolerances and machining allowances for castings
    Basis for stating as-cast versus machined acceptance on first castings.

Explore related company and product information

Prepare your sourcing request