In recent years, customer demand for custom non-standard fasteners has been steadily increasing, yet many newcomers to procurement still lack a clear understanding of the customization process for such components.

In fact, the customization processes for non-standard bolts and standard bolts are not significantly different.

The overall process for standard‑part bolts is divided into: preliminary confirmation (including standards, surface treatment, material, etc.), sample provision, formal production, shipment, and after-sales service.

For non-standard parts: preliminary confirmation (including drawings, surface treatment, material, etc.), sample production scheduling, formal manufacturing, shipment, and after-sales service.

The biggest difference between non-standard and standard parts lies in the preliminary confirmation and sample‑making process, which requires significantly more time.

The following is Longyan Duomeida’s complete customization process for non-standard parts. As procedures may vary among companies, this is intended solely as a reference for new procurement personnel.

I. Preliminary Communication

Normally, for the customization of non-standard fasteners, customers are required to provide the corresponding 2D or 3D drawings.

However, since some customers do not have dedicated technical staff to create drawings, we can also provide hand-drawn sketches or detailed specifications for custom fabrication.

Custom non‑standard fasteners require key specifications such as overall dimensions, thread length, head type, diameter, and quantity. Additionally, it is necessary to specify the intended application or required strength, whether a particular material is needed, and any special surface treatments.

II. Proofing and Verification

For the exterior design, 3D printing can be used, or a small‑batch prototype can be produced after the dimensions have been finalized. The factory first conducts measurements of dimensions and appearance, which are then handed over to the customer for their own verification.

If deviations in dimensions, thread specifications, or other parameters are detected during measurement, they must be promptly corrected and the sample resubmitted to the customer for re‑measurement until the sample is fully compliant.

III. Formal Production

1. Material Preparation: After the customer approves the sample or signs off on it, a purchase order is issued, and the factory arranges for the procurement of raw materials.

2. Cold heading/Hot forging: For non-standard bolts with a diameter of M30 or smaller, cold heading is typically used; in special cases, hot forging may be employed.

3. Thread Rolling: After the shaft is finished, perform thread rolling according to the confirmed thread profile.

4. Secondary machining such as turning and milling: Ordinary bolts do not require secondary machining. However, certain complex bolts may need precision finishing operations, including groove milling, drilling, and edge trimming.

5. Surface Treatment: For high-strength bolts or those with special requirements, heat treatment and galvanizing are required.

6. Inspection and Packaging: Once all the above steps have been completed, bulk production inspection and packaging can proceed.

In the production of non-standard fasteners, any issues encountered at each process step are promptly reported to the customer to confirm whether modifications are required.

If no issues arise, delivery may proceed as scheduled in accordance with the agreed lead time.

IV. Shipping and After-Sales Service

Pack and ship according to specifications, deliver to the customer’s designated address, and reconcile accounts for settlement.

If, upon receipt, the entire batch is found to have incorrect dimensions, materials, or thread specifications, the factory shall undertake rework or remanufacturing.