Straight Ejector Pins: Turning Mould Requirements Into the Right Part

Straight ejector pins are mould components with a straight pin configuration used in an ejector system. Selection is generally based on the dimensions and specifications required by the mould design.

For procurement, the important point is that a straight ejector pin should be selected from its complete specification rather than from the product name alone.

MISUMI India lists straight ejector pins in configurations using materials such as SKH51 high-speed steel and SKD61 equivalent die steel with nitriding treatment. The MISUMI catalogue also lists DIN-type straight ejector pins using SUJ2 equivalent + hardened material.

MISUMI India divides the straight ejector pin range into different configurations, making the first step to identify the type required by the mould design.

Selection factor	What to check	Procurement consideration
Shaft diameter	D/P dimension	Match the required mould specification
Overall length	L dimension	Confirm the required length before ordering
Head configuration	Head or collar specification	Verify compatibility with the mould drawing
Material	Specified steel grade	Match the required material specification
Surface treatment	Nitrided, hardened or other listed treatment	Select according to the required product specification
Shaft tolerance	Published tolerance	Important when dimensional fit is specified
Tip condition	Standard or tip processed	Select only the configuration required by the design
Special configuration	Gas release or other listed option	Use where the mould specification calls for it

MISUMI's No Tip Processing category specifically identifies D/P shaft diameter, material, shaft-diameter tolerance, surface treatment and head thickness as selection specifications.

1. Confirm the shaft diameter

Start with the shaft diameter specified in the mould design.

MISUMI India provides straight ejector pins with different shaft-diameter selections. For example, its SKH51 product range includes configurations where shaft diameter and overall length are specified or selected depending on the product type.

Do not select a diameter simply because it is available. Compare the required D/P dimension with the mould drawing and the applicable product specification.

For DIN-type SKD61-equivalent nitrided pins, MISUMI publishes the shaft-diameter ranges and associated dimensional tolerances in its catalogue.

2. Check the required overall length

The overall length is another primary selection parameter.

MISUMI offers several straight ejector pin configurations where L dimension selection or designation forms part of the product specification. The exact available lengths depend on the selected product family and shaft diameter.

When replacing an existing pin, compare the original part number and complete dimensional specification rather than assuming that a similar-looking pin with the same diameter will be interchangeable.

3. Match the material specification

Material should be selected according to the mould component requirement.

MISUMI India lists SKH51 high-speed steel straight ejector pins. Its product pages identify SKH51 as the material for several straight ejector pin configurations.

MISUMI also lists straight ejector pins made from SKD61 equivalent + nitriding treatment. The official MISUMI catalogue identifies the DIN D-EPN standard type with SKD61 equivalent + nitrided construction.

The MISUMI India mould catalogue additionally identifies 10PACK-D-EPU as a DIN straight ejector pin using SUJ2 equivalent + hardened material.

Therefore, material and treatment should be checked as part of the complete part-number selection rather than treated as interchangeable specifications.

Material selection becomes particularly important when comparing different MISUMI straight ejector pin configurations.

MISUMI configuration	Verified specification	Selection point
SKH51 straight ejector pins	High-speed steel SKH51	Compare when the mould specification calls for this material
D-EPN DIN straight ejector pins	SKD61 equivalent + nitrided	Compare according to the DIN product specification
10PACK-D-EPU DIN straight ejector pins	SUJ2 equivalent + hardened	Consider when this specified DIN configuration is required

The SKD61-equivalent DIN D-EPN catalogue data identifies a surface base of approximately 900 HV or higher and material hardness of 40–45 HRC. These values are catalogue specifications for that particular product family and should not be generalized to every straight ejector pin.

That distinction is important during procurement: the material and treatment should always be read against the exact MISUMI model.

A straight ejector pin can have different head or collar configurations depending on the product family.

For example, MISUMI India lists an SKH51 straight ejector pin with a 4 mm collar thickness, while another SKH51 product is specified with a JIS head/collar configuration.

This means two pins with similar shaft dimensions should not automatically be considered equivalent.

Before ordering, verify:

• Head or collar type
• Head/collar thickness
• Shaft diameter
• Overall length
• Material
• Applicable tolerance
• Surface treatment
• Product-specific configuration

This is particularly important when replacing an existing ejector pin, because the replacement needs to correspond to the mould's original component specification.

The tip condition is another important selection point.

MISUMI India has a dedicated No Tip Processing straight ejector pin category, where products can be compared using specifications including shaft diameter, material, shaft-diameter tolerance, surface treatment and head thickness.

MISUMI also provides a dedicated Tip Processed Straight Ejector Pins category. Its SKH51 tip-processed product is described as a straight ejector pin with shaft diameter and total length specification and straight tip machining.

The selection should therefore start with the mould drawing and specified ejector-pin end condition rather than assuming that all straight pins use the same tip configuration.

Gas-release straight ejector pins are a separate configuration within MISUMI's straight ejector pin range.

MISUMI India lists a Gas Release Straight Ejector Pins category and an SKH51 product described as a gas-release straight ejector pin with face cutting and shaft diameter/total length specification.

This configuration should be selected only when the mould design specifically calls for the corresponding gas-release feature. It should not be treated as a default alternative to a standard straight ejector pin.

MISUMI's range includes both standard and configurable straight ejector pin options.

The DIN catalogue identifies D-EPN as a standard straight ejector pin with SKD61 equivalent + nitrided material. It also lists D-EPN-L/D-EPNB configurations where L or L and P dimensions can be specified.

This distinction can be useful during procurement:

• Use a standard configuration when its published dimensions match the mould requirement.
• Compare selectable or specified dimensions when the standard configuration does not provide the required dimensions.
• Verify the complete part number before ordering.
• Record the selected part number for repeat purchasing.

The goal is not simply to find a pin that fits dimensionally, but to identify the exact configuration required by the mould design.

For purchasing teams, comparing complete specifications before ordering can reduce the risk of selecting a technically different replacement.

Check the following before finalising the part:

• Required straight ejector pin category
• Shaft diameter
• Overall length
• Head or collar configuration
• Material
• Surface treatment
• Shaft-diameter tolerance
• Tip condition
• Special configuration such as gas release, if required
• Required quantity and repeat-order requirements
• Exact MISUMI part number

MISUMI India's mould catalogue also identifies online availability of the mould component range and provides CAD data information for applicable products.

For repeat procurement, retaining the exact part number and specification against the mould reference can make future replacement orders more consistent.

Straight ejector pins should be included in routine mould-component replacement planning.

When a pin needs replacement, compare the existing component against the original specification rather than selecting a replacement based only on diameter or appearance.

The replacement check should include:

• Shaft diameter
• Overall length
• Head/collar configuration
• Material
• Surface treatment
• Dimensional tolerance
• Tip configuration
• Original MISUMI part number, where applicable

If the original part is no longer suitable for the mould design, the component specification should be reviewed before selecting an alternative configuration.

For organisations managing multiple moulds, standardising approved ejector-pin specifications and recording the corresponding MISUMI part numbers can also simplify repeat procurement.

Before ordering, verify:

• The selected category matches the mould requirement
• Shaft diameter D/P is correct
• Overall length L is correct
• Head or collar configuration is correct
• Material is correct
• Surface treatment is correct
• Shaft-diameter tolerance has been checked
• Tip processing is required or not required as specified
• Gas-release configuration is selected only when required
• Exact MISUMI part number has been verified
• Quantity is appropriate for the purchase and replacement requirement
• The specification is recorded for future reordering

The most reliable approach to selecting straight ejector pins is to work from the mould drawing and compare the complete component specification.

MISUMI India's straight ejector pin range includes multiple configurations covering different materials, dimensions, head/collar designs, tip conditions and special configurations. The Straight Ejector Pins category provides the starting point for comparing these options.

For a standard configuration, verify the published dimensions and material. For a replacement, match the complete original specification wherever required. When the mould requires a special tip or gas-release configuration, use the corresponding MISUMI category rather than substituting a standard pin.

By comparing shaft diameter, length, head configuration, material, treatment and tip condition together, procurement teams can make a more accurate component selection and maintain a consistent replacement record.