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AXIOMMOLDS

Leader Pins for Medium-Large Mold

Bolt-fixing leader pins for mold half alignment in medium to large injection molds. Three variants covering straight bolt-fixing, guiding assist pin option, and fully configurable length/diameter specifications.

Products in This Category

Straight — Bolt Fixing

Standard bolt-fixed leader pin. Ø40–Ø60mm.

Bolt Fixing — Guiding Assist Pin Option

With secondary pilot pin for initial approach alignment of heavy mold halves.

Configurable Length/Press-Fit/Mating

Selectable shaft Ø25–Ø80mm. All dimensions configurable.

3-Step Decision Guide

Is your mold over 1,500mm or do halves weigh >5 tonnes?
Yes
→ Bolt Fixing with Guiding Assist Pin
No
Do you need non-standard plate thickness or shaft diameter?
Yes
→ Configurable Length/Press-Fit/Mating
No
→ Straight Bolt Fixing (standard)

Decision rule: Use the 3-step approach: Step 1 — determine bolt-fixing vs press-fit based on plate thickness and mold temperature. Step 2 — size the diameter based on mold span and plate weight. Step 3 — add guiding assist pins if span-to-thickness ratio exceeds 8:1. For the complete decision flowchart, see our How to Choose Leader Pins for Large Molds — 3-Step Decision Guide.

Pairing

Required: Each leader pin must pair with a matched Leader Bushing (oil groove type) and Stopper Plate. Order as a set for matched tolerances.
Bolt Fixing Leader Pin Ø40
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Leader Bushing Ø40 + Stopper PlateFull guiding set for molds >800 mm
Guiding Assist Pin Ø20-30
⟷
Guiding Assist Bushing Ø20-30Mid-span supplementary guidance

Decision rule: Each leader pin diameter has exactly one matching bushing bore. Use the pairing chart to verify compatibility before ordering. For detailed guidance, see our What Is the Difference Between Guide Pin, Leader Pin, and Guiding Assist Pin?.

Application

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Large Mold Plate Alignment

Molds >800 mm where thermal expansion causes 0.05-0.15 mm plate misalignment without guided positioning.

Bolt-fixing leader pins maintain positive retention independent of thermal expansion — preventing the progressive misalignment that causes flash, core shift, and accelerated wear on all mold components.

Recommended: Bolt Fixing Ø40-Ø50 for molds >1,000 mm

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Multi-Plate Mold Guidance

Three-plate or stack molds where multiple separation planes require coordinated alignment across all moving sections.

Guiding assist pins at mid-span prevent plate flexure in long molds where the distance between corner leader pins exceeds 800 mm, eliminating center-span deflection.

Recommended: Guiding Assist Pins Ø20-Ø30 at mid-span positions

Decision rule: Leader pins for molds over 800 mm must use bolt-fixing retention. Press-fit retention is only suitable for molds under 500 mm where thermal expansion is manageable. For detailed guidance, see our What Is the Difference Between Guide Pin, Leader Pin, and Guiding Assist Pin?.

Frequently Asked Questions

Bolt fixing vs press-fit — when should I use bolt-fixing leader pins?+
Use bolt-fixing leader pins when the mold plate thickness exceeds 80 mm or the mold operates above 60°C continuously. In thick plates, press-fit insertion and removal requires excessive force that risks damaging plate bores. In hot molds, thermal cycling loosens press-fit interference over time. Bolt fixing provides positive retention with easy serviceability — pins can be removed and replaced without a hydraulic press.
What is a guiding assist pin and when is it needed?+
A guiding assist pin is a shorter, smaller-diameter leader pin installed between the main leader pins to provide intermediate support on very large mold plates (>1,200 mm). It prevents plate flexure at mid-span where the distance between corner leader pins is too great. Guiding assist pins are typically Ø20–Ø30 mm and extend only through the moving half, not the full plate stack. Use them when plate span-to-thickness ratio exceeds 8:1.
What shaft diameter range is available for configurable leader pins?+
Standard catalog offers shaft diameters from Ø20 to Ø60 mm with configurable overall length in 1 mm increments. The most common sizes for large molds are Ø30, Ø40, and Ø50 mm. Custom diameters up to Ø80 mm are available for die casting molds or molds exceeding 2,000 mm. All leader pins are precision-ground to h5 or h6 tolerance on the guiding shaft.

Engineering Resources

Selection Guide

How to Choose Leader Pins for Large Molds — 3-Step Decision Guide

3-step decision guide with application examples.

Terminology

What Is the Difference Between Guide Pin, Leader Pin, and Guiding Assist Pin?

Clarifying industry terminology across JIS, DIN, and ASTM standards.

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✓ Ø40–Ø80mm✓ Bolt-fixing in stock✓ MOQ 1 piece