JIS Standard M2 Steel Precision Stepped Ejector Sleeves

These precision stepped ejector sleeves are used as guiding components in injection molds where ejector concentricity directly affects smooth stroke, reduced wear, and stable part release. The wire-cut and polished boring internal geometry helps maintain controlled hole form, which is critical in high-cycle mold assemblies.

• Automotive connector and housing molds: Apply them in ejector systems to stabilize multi-pin or stepped ejector members during demolding, supporting consistent alignment even under repeated impact loading.
• Consumer electronics back covers and appliance housings: Use in molds that require tight assembly concentricity to prevent friction, chatter, and uneven ejector clearance—particularly when using stepped ejector designs.
• Precision die tooling and small mechanical parts: The sleeve’s stepped design and 0.01 concentricity specification make it suitable where guidance accuracy and repeatability are prioritized.

The M2 steel selection and precision boring process make this variant well-suited for long-running tooling that needs both wear resistance and controlled guidance.

This product is specified in SKH51 M2-type steel, an HSS family grade commonly associated with AISI M2 equivalent performance for hardness-retentive cutting and wear conditions. The key value for ejector sleeves is wear resistance in sliding contact and guidance surfaces, while maintaining sufficient toughness for normal demolding forces.

• Hardness/structure: Typically delivered in a hardened condition suitable for precision sliding components; final hardness depends on the supplier’s heat-treatment target for the selected geometry.
• Heat treatment approach: HSS grades like M2 (SKH51 family) are generally hardened via quench-and-temper cycles to balance wear resistance with toughness; excessive hardness can reduce toughness under shock, so the tempered state is important for stable guidance.
• Manufacturing process link: Wire-cutting followed by polished boring improves the internal hole surface quality, supporting lower friction and better fit repeatability.

Compared with lower-alloy, lower-hardness steels, HSS/M2-type material provides improved wear resistance; compared with higher-wear-only options, it trades off maximum brittleness resistance for a balanced toughness/wear performance suitable for precision ejector guidance.

Select the stepped ejector sleeve by matching the shaft diameter and stepped features to the ejector member and the mold’s guidance requirements. Start with the D (shaft diameter) range: 3.5 ~ 13 mm, then verify the P (tip diameter) range: 3.2 ~ 6.35 mm for the stepped interface.

• Hole/guidance geometry: Confirm V (hole diameter) within 0.8 ~ 2 mm, and match S (V hole diameter length) to the required engagement length (available ranges include 1 ~ 50, 1 ~ 22, 1 ~ 27, 1 ~ 37, 1 ~ 47 mm, depending on configuration).
• Overall length: Choose L based on the mold space and ejector stroke stack-up: options include 40 ~ 250, 40 ~ 125, and 40 ~ 175 mm.
• Concentricity and fit: The shaft diameter tolerance is specified as -0.01/-0.02, 0/-0.005. Use this to set clearance with the mating ejector part so guidance remains stable without binding.

For best alignment in assembly, ensure the step transitions correspond to your ejector’s stepped diameters, and account for the provided tolerances when selecting the final clearance fit.