Crosshead pin (wrist pin): Diameter 20-100 mm, Length 50-200 mm

Component Specifications

Definition

The crosshead pin, also known as a wrist pin or piston pin, is a hardened cylindrical component that serves as the pivotal connection between the piston and the connecting rod in reciprocating machinery. It transfers combustion forces from the piston to the connecting rod while allowing oscillating motion, and is typically press-fitted or secured with retaining rings in the piston bosses.

Working Principle

The crosshead pin operates as a bearing surface that allows the connecting rod small end to pivot relative to the piston during the reciprocating cycle. It converts linear piston motion into rotational crankshaft motion while withstanding high cyclic loads, shear stresses, and thermal expansion differentials.

Materials

Case-hardened alloy steel (e.g., SAE 8620, 4140), carburized or nitrided for surface hardness (58-62 HRC) with tough core; sometimes chrome-plated for wear resistance.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Length	50-200 mm
Diameter	20-100 mm
Hardness	58-62 HRC surface, 30-40 HRC core
Concentricity	0.005 mm
Surface Finish	Ra 0.2-0.4 μm
Straightness Tolerance	0.01 mm per 100 mm

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 286-2, DIN 71902, SAE J144

Parent Products

This component is used in the following industrial products

Crossheads

A reciprocating component in the power end of machinery that converts linear motion to rotational motion or vice versa.

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Engineering Analysis

Risks & Mitigation

Fatigue failure from cyclic loading
Wear and ovalization
Seizure due to inadequate lubrication
Retaining ring failure causing catastrophic damage

FMEA Triads

Trigger: Insufficient lubrication
Failure: Scoring, seizure, and accelerated wear
Mitigation: Implement oil pressure monitoring, use forced lubrication systems, specify proper oil viscosity

Trigger: Material fatigue from cyclic loading
Failure: Crack propagation and fracture
Mitigation: Use shot peening for compressive stress, implement regular ultrasonic inspection, maintain proper hardness gradient

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

ISO IT6-IT7 for diameter, geometric tolerances per ISO 1101

Test Method

Ultrasonic testing for internal defects, magnetic particle inspection for surface cracks, dimensional verification with CMM

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Crosshead pin (wrist pin)

Manufacturer profiles associated with Crosshead pin (wrist pin).

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Shaft Bearing

Precision component supporting rotating shafts in vibration motors to reduce friction and maintain alignment.

Frequently Asked Questions

What is the difference between a crosshead pin and a wrist pin?

In industrial terminology, 'crosshead pin' typically refers to larger machinery like compressors and diesel engines with separate crossheads, while 'wrist pin' is more common in automotive engines where the pin connects directly to the piston. Functionally they are similar.

How are crosshead pins lubricated?

They are lubricated through oil passages in the connecting rod (pressure lubrication) or via splash lubrication. Some designs include oil holes in the pin itself for distribution.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Crosshead pin (wrist pin)