Our company is a comprehensive gear manufacturer capable of integrated production — from turning to heat treatment.
The foundation of our technology lies in the expertise we have cultivated since our founding in 1931 (Showa 6).
By fully utilizing this technology, we have earned the trust of customers across various industries.
Before beginning any job, we always keep the following principles in mind:
- We believe iron is alive — we put our soul into every single gear we produce.
- We always strive to manufacture high-precision gears.
- We are committed to responding quickly to customer needs.
- To earn our customers’ trust and continued reliance, we make every effort to ensure quality, cost-efficiency, and on-time delivery.
“Smiling as we send off and receive guests,
Nurturing and cherishing the grass and trees,
As friends of the heart.”
– President
Perhaps the president wishes for us to approach gear-making with the same deep care and affection as we would have for nature.
The Art of Gear Manufacturing: Secret #1
Production begins with the purchase of round bars or forged materials, which are then cut to the required size for the next step. While material types are generally specified by the design, in rare cases we must select the most appropriate material for the intended application — a process that demands great care. Certain materials also require a heat-treatment process called “tempering” to stabilize molecular structure and reduce deformation or dimensional changes later. This step, like many others, depends heavily on experience and intuition.
The Art of Gear Manufacturing: Secret #2
In the turning process, round or forged materials are machined using lathes or milling machines. This step is performed while carefully considering the machining allowance needed for later gear cutting, as well as dimensional changes that will occur after heat treatment. In the tooth-cutting stage — the literal “gear cutting” — a key concern is preventing dent marks on the gear surface. To avoid sharp gear tips that are prone to damage, we use a semi-topping hob tool, which chamfers the gear teeth as they are cut. Since gears with dents are unusable, we also take great care during packaging and transportation.
The Art of Gear Manufacturing: Secret #3
Shaving is a post-gear-cutting process used to finely adjust tooth surfaces down to micrometer levels. This extremely precise operation is critical to bringing the gears to their final dimensions and must take heat treatment distortion into account. While this may appear tedious from an outside perspective, it is an essential process that ensures the accurate formation of the tooth profile and lead — considered the “lifeblood” of a gear. Before shaving, chamfering may also be done to help gears mesh more smoothly.
The Art of Gear Manufacturing: Secret #4
As noted earlier, most gears undergo heat treatment to enhance strength. However, overheating can make a gear brittle, while underheating leaves it too soft. During this process, we examine the gear’s cross-section under a microscope to confirm grain structure and collect data before proceeding. Since heat-treated parts always experience dimensional change, every process step must account for this. There are various heat treatment methods such as carburizing and tempering, gas nitriding, and induction hardening — each selected based on the material. For example, carburizing and tempering typically involve heating to 900°C for 8 hours, followed by tempering at 300°C for 2 hours. This requires specialized expertise and experience.
The Art of Gear Manufacturing: Secret #5
Though the tooth profile is mostly completed during the shaving stage, additional finishing of the inner and outer diameters is crucial to prevent axial misalignment in rotating gears. This step uses high-speed grinding wheels and involves working in microns. While it may seem like a subtle process, it is critical to the gear’s function as a transmission component. At this point, the gear is nearly ready for shipment.
The Art of Gear Manufacturing: Secret #6
After all previous steps, a final inspection is conducted. Using a state-of-the-art NC gear tester, we verify that tooth profile and lead fall within acceptable tolerances and that all dimensions meet specifications. For splines or gears that must mesh with specific counterparts, real-fit testing is also performed to ensure smooth rotation. If any issues arise, we apply corrective processes such as gear grinding or re-shaving to restore precision. If defects are beyond repair, the entire cost of material and labor is lost — a risk inherent in gear manufacturing.
This has been a brief introduction to the many steps involved in gear production. We hope it gives you a new perspective and deeper appreciation for the gears that are essential to everyday life.