The cheap part that costs more
On a mold bill of materials, ejector pins are among the least expensive line items and ejector sleeves among the more expensive. Choosing between them is not a cost decision; it is a question of where the push-off force needs to land and what it is allowed to mark.
What each part actually does
A ejector pin is a solid, headed rod that pushes the molded part off the core. It is simple, strong, and the default for the vast majority of ejector positions. A ejector sleeve is a hollow push-off that surrounds a core pin, so the entire annular face of a boss or a cylindrical feature takes the ejection load — not just the point where a pin would press.
That distinction matters in three common situations:
- Bosses and deep cylindrical features. Pushing off a hollow boss with a pin concentrates force where the wall is thin. A sleeve spreads it around the full circumference.
- Visible or cosmetic surfaces. A sleeve leaves an annular witness line instead of a point mark, which is often the difference between a part that ships and a part that does not.
- Core pins that need support. A sleeve can act as a guided support for a slender core pin, reducing deflection as the core fills.
Clearance is where sleeves live or die
An ejector sleeve runs on a close diametral clearance against its core pin. Get the clearance too tight and the sleeve galls or seizes as the tool heats up; too loose and flash works its way into the gap and the sleeve wears on the outside. The fit is specified in the mold component catalog by hole and core-pin diameter, and it should be re-checked whenever a core pin is replaced — a new pin in a worn sleeve is a mismatch even if both parts are nominally correct.
Where it sits in the component family
Pins and bushings are a system. Ejector sleeves, ejector pins, blades, core pins, sprue bushings, leader pins, and mold bushings all share the same fit-and-clearance conventions, and they are stocked as a coordinated set rather than as isolated parts. Ordering the sleeve without confirming the mating core-pin diameter is the most common way a routine mold repair turns into a second teardown.
Related catalog item: Tooling Components ejector pins and ejector sleeves, stocked to mold-component clearance conventions with mating core pins.
Contact Tooling Components for ejector component selection.