JIS Standard Steel Taperless Two-Step Core Pins Flat-Sides

Taperless two-step core pins are used to locate and support precision mold cores where repeatable engagement is critical. Unlike tapered designs, the two-step geometry provides a more controlled bearing/contact profile, helping maintain positional accuracy across high-cycle injection molding.

• Automotive and industrial connector housings: Suitable for locating core inserts for side-gating and internal rib features. The flat-side/two-step engagement supports stable core positioning when part eject forces and thermal cycling can shift components.
• Medical device injection molds: Applied in housings and cap components requiring tight dimensional consistency. Quenched hardened steel construction improves wear resistance at the locating interface, reducing positional drift over repeated cycles.
• Electronics and appliance overmolds: Used for core supports and alignment of fine internal cavities. The defined shaft diameter range (D/P 1–16 mm) and selectable tip/step shapes support fitting to specific cavity/core landing dimensions.

This series is offered in SKH51 and SKD61 hardened steels, both selected for stable performance at the core-pin locating interface. SKH51 is a high-speed steel commonly associated with AISI M2-class performance, providing strong wear resistance for fine-tolerance locating surfaces. SKD61 is commonly associated with AISI H13-class hot-work steel behavior, offering good toughness for tooling subjected to thermal cycling.

• Heat treatment state: The construction is specified as quenched hardened steel, supporting a hardened surface for repeatable fits.
• Hardness/behavior trade-off: SKH51 typically emphasizes wear resistance for long life at the tip/step contact, while SKD61 tends to balance toughness to better resist chipping or cracking under loading.
• Manufacturing: Two-step profiles and flat-side features are ground/finished to maintain the provided dimensioning ranges and tolerance conditions (e.g., L tolerance sets).

Select dimensions by matching the pin’s step geometry to the mating core/cavity pocket features. Start with the shaft diameter (D/P) in the range 1–16 mm so the bearing region controls alignment without excessive clearance. Then choose A/AAC (tip diameter) from 0.5–5 mm to match the intended locating/entry size in the core block.

• Length (L): Use L = 6.5–30 mm and apply the specified L tolerance options (0/-0.05 or +0.01/0), depending on whether you need tighter control toward engagement depth.
• Step shapes: Confirm the first step shape (CB/CC/CD/CE) and second step shape (B/C/D/E) along with tip shape (B/C/G/R/S/T) to ensure the contact profile matches the pocket.
• Fit considerations: Use the provided tolerance direction on L and the nominal diameter range (1.5–20 mm) to prevent under-engagement (too short) or interference (too long). Where dimensions are fixed (e.g., X = 0.1–1 mm), verify mating geometry accordingly.