SKH51 Steel Round Gate Transition Pin-Point Gate Bushings (SR)

Pin-point gate bushings like this round-transition SR type are used in injection mold tooling where repeatable micro-gate geometry is critical. The round gate transition helps smooth the melt pathway from the sprue/bushing area into the pin-point gate, reducing flow interruptions and supporting consistent gate size from cycle to cycle.

• Automotive connector housings: suited for high-volume parts that require stable pin-point gate formation to minimize gate vestige variation and maintain dimensional consistency.
• Consumer electronics enclosures: controlled tip geometry supports dependable gate forming when molding thin-walled features and when tighter control of gate freeze-off is needed.
• Medical device housings: helps achieve uniform gating behavior for precise filling, supporting repeatability where process stability is a priority.

With SKH51 steel and a controlled tip geometry variant, this bushing is appropriate when both wear resistance at the gate region and stable forming of the pin-point gate tip are required.

This SR bushing is made from SKH51 steel. SKH51 is an AISI M2 equivalent high-speed steel known for strong abrasion resistance at elevated temperatures experienced near the gate during repeated molding cycles.

• Heat treatment state: the product description indicates quenched hardening for wear resistance, supporting longer service life at the contact and eroding zones.
• Hardness & performance: quenched/hardened high-speed steels typically deliver high hardness and improved wear resistance, though ultimate toughness can be lower than more ductile tool steels.
• Geometry + material trade-off: the controlled tip geometry paired with hardened SKH51 helps maintain gate definition; however, the higher hardness means designs should avoid excessive mechanical shock and ensure proper alignment.

Compared with lower-alloy, pre-hardened steels, SKH51’s wear resistance is typically superior for gate-region erosion, while toughness is managed via appropriate hardening and geometry stability.

Select the bushing by matching the nominal diameter (No.) and the outer diameter D to the mold’s gate bushing bore and the sprue/gating layout. Available D (mm) ranges are 2.51–3, 3.01–4, 4.01–5, 5.01–7, 6.01–8, and 8.01–10, and the corresponding Nominal diameter No. (mm) options include 2.5, 3, 4, 5, 6, and 8.

• Verify the P (tip diameter) (mm) you need for the pin-point gate: options include 0.3–0.6, 0.5–0.9, 0.6–1.2, 0.8–1.5, 1–1.6, and 1.2–1.6.
• Choose the tip length C (mm) from 0.2–0.5, 0.3–0.8, or 0.5–1.5 to set the effective gate contact length.
• Match overall positioning using B (length excluding head/tip) and L (L dimension) ranges (e.g., B: 4–6 up to 5–50; L: 8–25 up to 15–60).

Maintain the specified P dimension tolerance of ±0.01 when designing gate repeatability; tip straight tolerance is variable (0–0.2 or 0–0.05), so ensure your cavity/core finish and alignment support the intended fit.