Heat Treated Spline Bushing

The spline bushing is the most easily overlooked yet most troublesome part in an entire machine. Sandwiched between the external spline shaft and the driven component, it is responsible for transmitting torque steadily while withstanding frequent start-stop cycles, shocks, and dust. After more than ten years of making spline parts in our workshop, our deepest insight is this: once the bushing wears out first and the tooth surface loosens, the entire shaft is scrapped along with it-and the cost of a single replacement for the customer is often dozens of times the price of the bushing itself. That is why when we make a Heat treated spline bushing, we never treat "it works" as the standard. Instead, we make it "worthy of your shaft," relying on solid materials and craftsmanship rather than empty promises.

We commonly use alloy steels such as 20CrMnTi, 42CrMo, and 40Cr. First, quenching and tempering build up core toughness; then the tooth surface undergoes carburizing quenching or induction quenching, with surface hardness stabilized at HRC 58–62 and an effective case depth of 0.8–1.5mm. The tooth surface is ground to within Ra0.8μm-hard on the outside, tough on the inside, resisting both wear and brittle fracture. Internal splines are machined per DIN 5480, ISO 4156, or ANSI B92.1 standards, with tooth side precision controlled at 6H/7H and concentricity between the inner bore and outer diameter within Φ0.02mm. When a Heat treated spline bushing is made to this level, it basically needs no adjustment once installed-torque transmission is smooth and no vibration is introduced into the system. Every Heat treated spline bushing goes through full inspection before shipping: tooth profile and lead are measured on a gear inspection center, and key dimensions are sampled on a CMM. This is the same process we use for Volvo and Ford OEM supply. Send us your drawings-custom samples are typically ready in 15–20 working days, faster for simpler processes. We accept small batches too, and the sample fee is fully deductible against bulk orders. Make a few, install them, and if they work well, we can talk volume.

● Agricultural machinery gearboxes, rotary tillers, harvester drives

● Spline connections for hydraulic pumps and hydraulic motors

● Construction machinery (excavators, loaders) drive shafts

● Industrial reducers, wind power, passenger vehicle gearboxes

Established in 2009, our factory is located in Yuhuan, Taizhou-China's automotive parts manufacturing base. The plant covers over 5,000 square meters with more than 60 employees. The workshop houses over 100 precision CNC machines, including lathes, machining centers, turn-mill composites, and grinders, plus 2 forging lines. From blank to finished product, turning, milling, grinding, heat treatment, and surface treatment are all completed in-house. We control delivery and quality ourselves, without relying on subcontractors.

Operating under the IATF 16949 system: incoming material inspection, in-process patrol inspection, and 100% final inspection before shipment. Spline tooth profile and lead inspection reports are provided, key dimensions are CMM-sampled, third-party inspection is accepted, and reports accompany the goods.

Customization from drawings and reverse engineering from samples are supported, with no strict MOQ. Custom samples take 15–20 working days, shorter for simple processes and appropriately longer for complex ones. A small sample fee is charged, fully deductible against bulk orders.

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