JIS Standard Steel Two-Step Core Pins Flat Sides

Two-step core pins with flat guidance surfaces are commonly used in precision injection mold assemblies where repeatable ejection and stable alignment are critical. The flat sides help maintain rotational orientation of the core pin during setup and operation, reducing misalignment risk that can disturb the core-to-cavity relationship.

In automotive connector and sensor housing molds, the two-step profile provides controlled tip geometry and improved guidance as the core pin enters and exits the molded part. This supports consistent ejection across tight cycle windows, especially when the contact zone experiences frequent sliding.

For medical device housings and inspection-ready components, stable positioning reduces variability in feature formation near the pin interface. The hardened steel construction supports wear resistance under repeated molding cycles while maintaining dimensional stability.

When you need reliable ejection in high-precision electronics and small-diameter core builds, the variant’s tight L dimension tolerance (+0.01/0) and the specified tip gradient tolerance ±0.005 make it suitable for core fit and consistent guidance.

This series is available in SKH51 and SKD61, both hardened steel options selected for durable core-pin performance under sliding contact. SKH51 is typically treated as an AISI M2 equivalent high-speed steel grade, known for strong wear resistance and good toughness balance in tool steels.

SKD61 corresponds to H13 equivalent hot-work tool steel, widely used where heat checking and thermal fatigue resistance matter in molding service.

• Heat treatment state: Hardened steel construction is specified for durable ejection and repeated cycles (exact hardness level is not provided in the input data).
• Wear vs. toughness trade-off: M2-class SKH51 generally emphasizes wear resistance at sliding interfaces, while H13-class SKD61 is often selected for more balanced high-temperature tooling durability.
• Manufacturing process: precision machining is followed by hardening and finishing to achieve the tight dimensional requirements such as the L tolerance (+0.01/0) and specified tip geometry tolerance.

Hardness (HRC): Not specified in the provided metadata.

To select the correct two-step core pin size, match the required D/P (shaft diameter) first. This series supports D/P = 1 ~ 20 mm, so choose the diameter that corresponds to the core pin bore and functional sliding clearance in your mold.

Next, verify the axial length using L = 6.5 ~ 100 mm. The input data specifies a tight L dimension tolerance of +0.01 / 0, so ensure the pin length does not exceed your assembly’s available space while still meeting guidance depth requirements.

• Two-step geometry selection: Choose the first step shape from CA, CB, CC, CD, CE and the second step shape from A, B, C, D, E, then confirm the step diameters using A = 0.5 ~ 10 mm and E (tip diameter) = 0.5 ~ 5 mm.
• Step/feature dimensions: Confirm taper width C (given ranges including 0.1 ~ 0.2, 0.1 ~ 1, and an additional listed range), and tip/bearing-related widths such as G = 0.1 ~ 0.5.
• Fit considerations: Because L tolerance is strictly controlled and tip gradient is listed as ±0.005, validate that your core positioning and ejector alignment will not force the pin into binding during repeated cycles.

Where exact lengths or reduced versions are required, use the configurable FC option (ranges listed per configuration) to shorten F below the minimum.