One Step Round Core Pins
Single diameter transition creating two distinct cylindrical sections. The most common stepped configuration for counterbored holes.
Products in This Category
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61 Steel One-Step Core Pins - No Second Step | Configurable Opti
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
JIS Standard SKD61/SKH51 Steel Straight Core Pins | OEM Available
Straight Core Pins in SKD61/SKH51 Steel with Core Pin. Engineered for plastic injection molding with custom options. Con
Step Configuration Guide
One-step pins create a single diameter transition. Key decision: standard vs radiused step profile.
| Variant | Description | Best For | Recommendation |
|---|---|---|---|
| Standard Transition | Sharp 90° step between diameter sections | Non-critical stress applications, most counterbored screw holes | Default — lowest cost |
| Radiused Transition | Controlled fillet radius at the diameter change | High-stress applications, thin pins (<2 mm), high-cycle molds (1M+ shots) | Fatigue resistance for critical pins |
| Flat-Sided | Anti-rotation flat ground on one side of the shaft | Features requiring angular orientation control relative to other mold elements | Add when rotational alignment matters |
One-Step or Something Else?
One-step pins form exactly two internal diameters. Confirm your cavity geometry matches:
✅ You're in the right place if:
- Your cavity requires exactly two concentric internal diameters with a step transition
- The internal feature is a counterbored hole, stepped bore, or shoulder recess
- A single diameter change is sufficient — you do not need three sections
🔄 Consider switching to:
- Need three concentric diameters? → Two-Step Core Pins
- Only need a single uniform diameter? → Straight Core Pins
- Stepped cavity has gas trapping at the transition? → Stepped Gas Release Pins
About One-Step Core Pins
A counterbored screw hole requires a large-diameter recess on top and a smaller through-hole below. One-step core pins combine both diameters into a single pin body, reducing mold complexity and ensuring perfect concentricity between sections — since both are ground on a single workpiece.
Head thickness is standardized at T = 4 mm (JIS). Available in SKH51 for general-purpose applications and SKD61 for elevated-temperature molds. Extra-precision grades provide tighter concentricity for critical applications such as optical lens housings or high-precision connector seats.
For cavities that require gas venting through a stepped pin, gas release one-step variants are available with flat-sided or SVC venting geometry.
Application Scenarios
See how this product type solves real engineering challenges across different industries and applications:
Stepped Bore Housing Features
Pain point: Many plastic housings require a stepped internal bore — a larger diameter for component seating and a smaller diameter for retention — traditionally requiring two separate core pins or complex side actions.
Why it fits: One-step core pins form both diameters in a single pin, eliminating pin-to-pin alignment errors and reducing mold complexity. The step transition is precision-ground for clean part geometry.
Connector Pin Receptacle Cavities
Pain point: Electrical connectors require precise stepped cavities to house pin receptacles — the larger step provides insertion clearance while the smaller step ensures contact retention force.
Why it fits: One-step geometry matches standard receptacle dimensions. Tight tolerance on both diameters ensures consistent contact retention across all cavities in multi-cavity tools.
Medical Syringe Barrel Cores
Pain point: Syringe barrels require a stepped internal profile — larger bore for the plunger seal area and smaller bore for the needle hub — with biocompatible surface finish requirements.
Why it fits: STAVAX ESR material provides corrosion resistance for medical-grade resins. One-step profile eliminates secondary machining of the internal step, maintaining concentricity critical for plunger seal.
Related Categories
Frequently Asked Questions
What is the difference between one-step and two-step?+
Can one-step pins form blind holes?+
What concentricity can I expect?+
Engineering Resources
Case Studies
Need a Custom Quote?
Send your specifications — material, dimensions, quantity — and receive a quote. MOQ: 1 piece. Custom dimensions available.