JIS Standard SKD61 Steel Stepped Ejector Sleeves

Stepped ejector sleeves in SKD61 with a nitrided surface are commonly used in injection mold toolsets where long-term guidance and consistent ejection force transfer are critical. The stepped geometry seats into a matching stepped bore, helping maintain alignment during cycling.

• Automotive connector and housing molds: Use these sleeves on ejector systems that experience high repetition and abrasive contamination. The nitrided surface supports stable sliding and improved wear resistance, helping reduce variation in ejection stroke.
• Appliance and consumer electronics enclosure molds: Stepped sleeves are suited for precision ejection where smooth movement prevents scuffing and misalignment. The controlled H7 inner-diameter tolerance supports reliable fit with the mating ejector elements.
• Industrial housings requiring repeatable ejection: For toolsets that must hold geometry over many production cycles, SKD61 steel plus surface nitriding improves abrasion resistance while retaining toughness for reliable ejector operation.

This component is made from JIS SKD61 steel (H13-equivalent class tool steel), selected for its balance of hardness, toughness, and hot-working performance in mold bases and ejector parts. After machining, it is typically supplied in a heat-treated condition appropriate for ejector guidance; the defining wear-improvement feature here is the nitrided surface treatment.

• Nitriding: Produces a hard, wear-resistant surface layer that resists abrasion from ejector sliding and particulate contamination.
• Hardness / trade-offs: Nitrided surfaces improve wear resistance, while the core remains tougher for shock resistance during ejection events.
• Wear vs. toughness: Compared with through-hardened approaches, nitriding targets surface durability while preserving the SKD61 core’s toughness for stable operation under cyclic loading.

Select the stepped ejector sleeve dimensions by matching the cavity/core interface and the mating ejector shaft requirements. Use D (shaft diameter) = 4–10 mm to fit the ejector shaft you intend to guide, and choose P (tip diameter) = 3–6 mm and V (hole diameter) = 1.5–3.5 mm to reflect the stepped features in your mold assembly.

• Recess and locating features: Match C (recess diameter) = 2–4 mm and Dimension N = 17–24 mm to the stepped bore seating geometry.
• Length control: Confirm L (L dimension) options: 50–300, 70–300, 50–200, or 50–250 mm based on your required ejection travel and tool stack-up; verify S (V hole length) = 20–50 or 20–100 mm.
• Tolerance and fit: The sleeve includes a controlled H7 inner-diameter tolerance; ensure the mating shaft tolerance is compatible to achieve stable guidance with minimal play.