JIS Standard SKH51 Steel Stepped Two-Step Center Pins

Stepped two-step center pins are used in injection mold tooling and die assemblies where repeatable part positioning and guiding stability are critical. The stepped geometry creates controlled engagement at two levels, helping maintain centering and reducing lateral drift during high-cycle operation.

• Automotive connector and small housing molds: Ideal for locating features that must align under repeated clamping, because the two-step engagement improves stable alignment as the pin repeatedly mates with bushings/locating holes.
• Medical device housings and precision enclosures: Suited for guiding thin, precision inserts where consistent concentricity matters; the variant’s stepped two-step form supports reliable centering during cycle-to-cycle variation.
• General die sets with tight locating fits: Works well when the assembly requires accurate shaft-to-hole relationship; the tight shaft tolerance supports dependable guidance and stable pin engagement.

This variant is matched to precision locating/centering roles, combining a wear-resistant steel selection with tight shaft dimensional control.

This product is made from JIS Standard SKH51 steel, commonly used for wear-resistant, precision tooling components. While SKH51 is a high-performance tool steel, its key advantage here is its quenched condition for improved hardness and resistance to wear at the pin-to-locating interface.

• Heat treatment state: Quenched SKH51 steel (as specified for this variant).
• Property focus: Enhanced wear resistance for long service life under repeated sliding/engagement.
• Trade-off: As hardness increases, extreme toughness and impact resistance may be comparatively lower than tougher grades—making it important to avoid applications with severe shock loading.

If your application demands higher toughness over wear, alternative steel grades may be considered; however, this SKH51 variant targets stable guiding and controlled centering with wear durability.

Select the center pin dimensions by matching the locating requirements of the mold core/cavity interface and the mating holes/bushings. Start with the D/P (shaft diameter) in the range 1 to 10 mm, and confirm the intended fit using the available shaft tolerance: 0 / -0.005 mm.

• Choose the stepped geometry: Select the Step Shape (A, B, C, D, E) and the corresponding second step type (A, B, C, D, E) to align with your two-level locating pattern.
• Verify stepped root and tip sizes: Set D (stepped root diameter) within 1.5 to 12 mm, and select tip dimensions such as A (0.51 to 2.5 mm) and E (0.5 to 2.5 mm). Tip chamfer widths (G) are fixed in the 0.1 to 0.5 mm range per model data.
• Match length: Use the specified F (shaft diameter length) of 5.5 to 55 mm and overall L ranges (e.g., 70–200, 70–250, 100–300, 100–350, 100–250) to ensure correct engagement depth.

Account for the pin’s tight shaft tolerance when selecting the mating bore size; the pin is dimensioned to a controlled maximum with limited negative deviation to support repeatable guidance.