JIS Standard SKH51 Steel Precision Stepped Ejector Sleeves (ESVF)

These precision stepped ejector sleeves are used inside injection mold ejector assemblies where stable, low-deflection guiding is critical. The thin-wall stepped geometry helps maintain alignment as the ejector stroke loads increase, supporting repeatable positioning from shot to shot.

• Automotive connector and housing molds: In molds with closely spaced ejector pins, the stepped guide provides stable support and consistent alignment during ejection, helping reduce side loading on mating components.
• Consumer electronics enclosure molds: For thin-wall parts requiring tight ejector alignment, the controlled inner diameter and shaft interface allow smooth motion and reduce misalignment over long production runs.
• Medical device housings: Where dimensional stability and reliable ejection are required, the ESVF configuration supports accurate guiding in systems that see frequent cycling.

The SKH51 variant is suited for these applications because it is a precision ejector-steel grade designed for wear resistance at the guiding surfaces, while the stated ID/shaft tolerance targets consistent fit.

JIS Standard SKH51 steel is used for precision ejector sleeve components. In tooling terms, SKH51 is commonly selected for high hardness performance and wear resistance, supporting long service life in guided ejection.

• Hardness / wear-toughness balance: The design description specifies quenched and hardened performance for wear resistance. This typically improves surface durability, but requires attention to maintaining adequate toughness to avoid chipping under shock loading.
• Heat treatment state: Quenched and hardened condition is the stated requirement for this product family, targeting stable dimensions in the sliding/guiding region.
• Manufacturing relevance: Achieving the tight inner diameter tolerance (+0.005 / 0) and shaft tolerance (0 / -0.005) typically depends on precision machining plus finishing after heat treatment.

If alternative tool steels are considered, they must similarly support high wear resistance while maintaining sufficient toughness for ejector impact; SKH51 is positioned for that guiding-surface durability requirement.

Select the sleeve dimensions by matching the ejector assembly geometry to the mating ejector pin/shaft and the guide bore requirement in the mold. The key interfaces are the shaft diameter (D), the sleeve tip diameter (P), and the hole diameter (V).

• Step 1—Match shaft diameter: Choose D = 2.5 ~ 6 mm to correspond to the ejector shaft you will guide.
• Step 2—Match stepped tip and bore features: Select P = 1.8 ~ 2.9 mm and V = 0.8 ~ 1.6 mm to align with the stepped interface and the functional hole geometry.
• Step 3—Match lengths to cavity/core thickness: Pick L = 40~70, 40~125, or 40~150 mm and the corresponding N = 20~60, 20~115, or 20~140 mm so the guided length covers the region where alignment must be maintained.

Fit is governed by the stated tolerance goals: inner diameter +0.005 / 0 and shaft tolerance 0 / -0.005. Ensure the mating shaft lands within the intended tolerance window to achieve consistent clearance and avoid binding.