JIS Standard Steel Precision Taperless Two-Step Core Pins Flat-Sided

This hardened, flat-sided two-step core pin is used in injection mold tooling where repeatable core locating and resistance to rotation are critical. The two-step taperless seating supports stable positioning of the core over repeated cycles, helping maintain consistent core-to-cavity alignment.

• Automotive connector and housing molds: Flat-sided geometry helps prevent core rotation during ejection, supporting stable ejection accuracy when cores experience intermittent side loads.
• Medical device housings and caps: The taperless two-step layout improves core support at the seating surfaces, which is beneficial when tight dimensional repeatability is required across high-volume production.
• General electronics housings: Hardened steel and the specified shaft fit tolerances support long service life under abrasion from repeated alignment and runner/core movement.

With flat-sided contact, the pin variant is especially suited for applications where rotation control and consistent seating are needed to protect cavity formation and downstream part tolerances.

These taperless two-step core pins are available in SKH51 or SKD61 hardened steel options, both intended for wear resistance in core locating service.

• SKH51: Typically selected for abrasion resistance where higher hardness is beneficial. Expect a trade-off of reduced toughness versus tougher tool steels if heavily shock-loaded.
• SKD61: Commonly chosen for balanced hot-work tool performance, supporting better toughness for molds that experience thermal cycling and intermittent mechanical stress.

In manufacturing, pins are precision machined to the required taperless two-step geometry, then supplied in a hardened condition suitable for stable wear behavior. Final inspection focuses on the shaft diameter and seating features to maintain the specified fit tolerance range of +0.01/0 to 0/-0.05 (by length/dimension as provided in the spec).

Choose SKD61 when toughness and thermal cycling durability are priorities, or SKH51 when wear resistance at the locating surfaces is the dominant requirement.

Start by matching the pin’s shaft diameter D/P to the mold’s core guide bore. This product supports D/P = 1 to 20 mm, so select the closest nominal diameter and verify that the pin can achieve the intended fit using the provided tolerance window (referenced as +0.01/0 to 0/-0.05).

• Match the seating length L: The available L = 2.2 to 100.01 mm must cover the required engagement and support depth at the two-step locating surfaces.
• Select step geometry: Choose the first step shape (CB/CC/CD/CE) and second step shape (B/C/D/E) that correspond to your core locating profile. Fixed taper widths include X = 0.1 to 1 mm and C = 0.1 to 1 mm.
• Confirm bearing bore length F: Use F = 12 to 28 mm and the FC option ranges (e.g., 5 to 12.79, 5 to 27.99, 5 to 11.99 mm) to ensure the effective length does not undercut your design minimums.

Because step/tip features (tip diameter A 0.5–5 mm, chamfer widths, and tip angle K) vary, verify the bearing contact area and clearance against the core bore before final assembly.