Case review: 5 small module gear models, module 0.25-0.3, ISO 1328-1 grade 5-6, through-hardened 50-60 HRC, 4,000 pcs each (20,000 total), in 42CrMo4, 16MnCr5 or X8CrNiS18-9.
In August 2026, a transmission parts trading company from East China came to Geyon Transmission with drawings from an end customer: five models of small-module gears, modules 0.25 and 0.3, precision ISO 1328-1 class 5-6, through-hardened 50~60 HRC, 4,000 pieces per model, 20,000 pieces in total, with the smallest pitch circle only about 3 mm. The customer does not machine parts itself, and its accountability to the end customer rests entirely on the supplier’s inspection reports. Geyon Transmission first conducted a drawing review and material recommendations, then defined the process route and quality control plan, with inspection data archived piece by piece. This review breaks down the quality control essentials of a batch order for small-module gears.
The customer is in the transmission parts trade, supplying equipment such as gearboxes year-round. This order came from an end customer, with five drawings, models 54.0957.001 to 54.0957.300, tooth counts 11 to 59, and two modules, 0.25 and 0.3. Three material options were given: 42CrMo4, 16MnCr5, and the free-cutting stainless steel X8CrNiS18-9 — stainless steel being among the options suggests the end application is most likely related to corrosion resistance, common in equipment for food, medical and similar sectors. Heat treatment was uniformly specified as through hardening, with tooth surface hardness of 50~60 HRC.
The trading company does not touch machining itself. Every tolerance and every hardness value on the drawings must ultimately become numbers on an inspection report, passed on to the end customer for acceptance. Whether this batch can be taken on, and how, comes down to the supplier’s engineering capability and quality control system.
Engineering review first, then process and quality control — three steps.
Step one, drawing review. All five PDF drawings were parsed and archived, with tooth count, module, profile shift, material and heat treatment checked item by item. The machining datum and inspection method for small-module gears were fixed at the review stage.
Step two, material and heat treatment recommendations. 16MnCr5 carburizing and hardening suits small gears subject to alternating loads; 42CrMo4 through hardening has a mature process and suits conventional operating conditions; stainless steel X8CrNiS18-9 handles corrosion-resistant scenarios. Recommendations were given according to the end operating conditions for the customer to confirm.
Step three, process and quality control. For small-module gears, precision CNC turning ensures the internal and external cylindrical datums, while the tooth profile is ensured by high-precision hobbing or gear grinding. Inspection relies mainly on span measurement over pins (pin distance), combined with projection magnification to check the tooth profile, with pitch, profile, helix and hardness recorded item by item. Three inspection stages — incoming, in-process and outgoing — follow the procedure, and mass production is released only after first-article full-dimensional confirmation.
On the gear inspection system side, Geyon Transmission has a complete setup: a gear measuring center covering modules 0.5 to 20, Rockwell, Vickers and Brinell hardness testing in full, and a roughness tester with resolution down to 0.001 μm. For small-module parts, span measurement over pins and projection inspection are added as a double safeguard.
| Item | Result |
|---|---|
| Product | 5 models of small-module gears (54.0957.001~300) |
| Module/tooth count | M0.25~0.3, tooth count 11~59 |
| Precision | ISO 1328-1 class 5-6, inspected item by item with reports issued |
| Hardness | Through hardened 50~60 HRC |
| Batch | 4,000 pieces per model, 20,000 pieces in total |
| Material options | 42CrMo4 / 16MnCr5 / X8CrNiS18-9 |
| Engineering output | All 5 drawings parsed and confirmed, process route and quality control plan defined |
| Inspection delivery | Pitch/profile/helix/span measurement over pins/hardness recorded piece by piece, full set of reports shipped with the goods |
Data from the SXQ092 inquiry drawings and engineering review records.
First, the drawing review was done up front. How small-module gears are to be inspected and how the datums are defined were made clear at the quotation stage, saving rework later.
Second, the material recommendations were given clearly. Three grades correspond to three operating conditions; the customer took them to confirm with the end customer, which is easier than guessing from the grade designations themselves.
Third, the quality control flow was unified. All 20,000 pieces went through the same set of incoming, in-process and outgoing inspections, with data archived piece by piece, so the trading company has something to stand on when answering to the end customer.
Is your end-customer order also small-module, high-precision, batch delivery? Send the drawings over, and the Geyon Transmission engineering team will first conduct a drawing review, then reply with the process plan, inspection items and quotation. With 13 years of experience in the gear industry, gear grinding precision up to DIN class 3, and support for issuing a full set of inspection reports to DIN/ISO/AGMA standards.
More information: Geyon Transmission website | Small-module precision gear customization | Gear inspection system | Transmission parts trade support
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