The two parts above belong together: a stainless steel hub made by metal injection molding (MIM), with an internal spline formed in the mold, and the machined spline shaft it engages. One moves the torque; the other carries it. Supplied separately, they are two tolerancing problems. Supplied together, they are one assembly that fits the first time.
What MIM does well
Metal injection molding is the economical route for small, complex stainless geometry — the internal spline, the cam profile and the mounting lug on this part are all formed to net shape, with only critical faces machined afterwards. For volumes of thousands of pieces, MIM delivers repeatable density and strength at a fraction of machining cost.
Why the shaft is machined, not molded
The external spline is a different story. Spline accuracy, surface finish and case hardness decide how smoothly the joint runs and how long it lasts, so the shaft is machined from bar and finished to the profile the hub needs. The two processes are chosen because each is the best for its half — not because one is cheaper on paper.
The point of ordering them together
An internal spline and its shaft form a tight kinematic pair. When both halves come from one supplier with one inspection record:
- Tooth thickness and space width are checked against each other, not against two separate drawings
- Fit is verified on a go/no-go gauge before packing — assembly clearance is measured, not hoped for
- Material certificates (EN 10204 3.1) cover the set, with heat-number traceability
That is how we ship matched gear-train parts to European crane and hoist builders: full dimensional inspection on both halves, documented together, packed together.
Sending us your inquiry
Send the drawing — or just photos of the part and its mating shaft, like these. We quote within 24 hours and tell you honestly whether MIM, machining or a combination is the right route for your volume.
Need these parts made to your drawing? Send your specification — clear quotation within 24 hours, EN 10204 3.1 certificates as standard.
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