What is the difference between a rod eye and a rod end?

A rod eye is a solid forged eye with a threaded shank and no bearing, giving a simple single-axis pivot. A rod end has a spherical bearing for multi-axis articulation.

What does RER versus REL mean?

RER is the right-hand thread rod eye; REL is left-hand. They are used together for adjustable assemblies.

What sizes of rod eyes are available?

Bore and thread #8 to #14 across 6 sizes. See the spec page for dimensions.

Forged Threaded Eye Ends for Cylinders & Linkage

Rod Eyes

Q: Can a rod eye replace a rod end?

Only where the joint moves on a single axis. If the linkage needs angular misalignment, use a rod end.

A rod eye is a solid forged eye end with a threaded shank — a simple, rugged pivot point for cylinders, springs, shocks and linkage, without a spherical bearing. SYZ rod eyes are carbon steel, zinc plated, in right-hand (RER) and left-hand (REL) thread, bore/thread 1/2 x 1/2 to 5/8 x 5/8, 6 sizes.

Browse Rod Eyes Sourced Series ↓ Request a Bulk Quote

Forged

Solid eye end

Carbon steel

Zinc plated

RER + REL

RH / LH thread

1/2 x 1/2 to 5/8 x 5/8

Size range

Material Certs Available

Sample to Full-Container

Factory Direct Sourcing

Industry Standards Cross-Ref

ISO 9001:2015 Quality

Overview

What Is a Rod Eye?

A rod eye (eye end) is a one-piece forged fitting with a circular eye (for a pin/bolt) and an integral threaded shank. Unlike a rod end, it has no spherical bearing — it provides a simple single-axis pivot. It’s the economical choice for cylinder rods, spring/shock mounts and basic linkage where multi-axis articulation isn’t needed.

Forged One-Piece Body

A rod eye is a simpler forged eye-end without a spherical bearing, making it the right fit for single-plane pivots on cylinder rods, springs and basic linkage.

RH & LH Pairing

RER and REL let you keep right-hand and left-hand thread logic consistent with the rest of the linkage, especially when matching rod ends or spring hardware.

Product Offerings

Series

View Spec & Size Charts →

Series	Material	Sizing	Notable
Rod Eye (RER / REL)	Carbon steel, zinc plated	Bore/thread 1/2 x 1/2 to 5/8 x 5/8	6 sizes; RER = RH, REL = LH; forged precision

Engineering Guide

Selection Guide

Single-Axis or Multi-Axis?

Need a simple single-axis pivot with no articulation → rod eye; need multi-axis / misalignment capability → use a rod end instead.

Pick Thread Hand

Pick RER (right-hand thread) or REL (left-hand thread) to match your rod or adjuster. Use RER + REL together for adjustable-length assemblies.

Match Thread & Eye Bore

Match thread to the rod and bore to the pin/bolt for a close fit; confirm eye dimensions and pin shear on the spec page.

Industrial Uses

Applications

Hydraulic/pneumatic cylinder rod ends, spring and shock mounts, simple control linkage, and machinery pivots that hinge on one axis.

Hydraulic & Pneumatic Cylinders

Cylinder rod end fittings where the eye attaches to a pin and the shank threads onto the cylinder rod — single-axis pivoting under load.

Most common application

Spring & Shock Mounts

Attaching springs or shock absorbers at a single pivot point where no angular misalignment compensation is needed.

Suspension & linkage

Simple Control Linkage

Basic machinery control linkages, actuator connections and control rod ends that hinge cleanly on one axis without misalignment.

Machinery & agricultural

Machinery Pivots

Single-axis machinery pivots and pin joints where the forged construction provides better fatigue strength than machined alternatives.

Industrial equipment

Technical Guide

Rod Eye vs Rod End vs Clevis — Choosing the Simplest Joint That Works

A rod eye is the most basic of the three pivot fittings — and often the right answer when designers over-spec a spherical rod end out of habit:

	Articulation	Construction	Choose when
Rod eye	Single-axis pivot, no bearing	One-piece forged eye + shank	The joint hinges on one pin axis; no misalignment needed
Clevis / yoke	Single-axis hinge	Fork + cross pin	Same single-plane motion but you want a fork-and-pin interface
Rod end (heim joint)	Multi-axis (spherical)	Ball-in-housing + thread	The joint must tilt out of plane / absorb misalignment

Because it has no spherical bearing to wear, a forged rod eye is rugged, cheap and maintenance-light — ideal for cylinder rods, spring/shock eyes and basic linkage. The trade-off is zero misalignment capability: if the mating geometry tilts off-axis, the pin binds and you need a rod end instead.

Fitting checklist: match the thread (and hand — RER right-hand, REL left-hand for adjustable pairs) to the rod; match the eye bore to the pin/bolt for a close fit; confirm the eye dimensions and pin shear on the spec page; lock adjustable assemblies with a jam nut.

Material Science

Why “Forged” Matters Here

These rod eyes are forged, not machined from bar or cast. Forging aligns the steel’s grain flow around the eye, giving better fatigue strength and impact resistance than a cast or simply-machined eye of the same size — which is why forged eyes are favored on cylinder rods and spring/shock mounts that see repeated load reversals. The zinc plating then protects the forged steel from surface rust in normal service (not salt/marine — use stainless for that).

Engineering Detail

Sizing & Failure Modes

Two dimensions drive a rod eye selection: the thread (to the rod) and the eye bore (to the pin). Get either wrong and the joint either won’t fit or wears fast.

Symptom	Cause	Prevention
Pin bore wallows / elongates	Bore too large for pin (slop)	Match bore to a close fit on the pin/bolt
Eye cracks at the neck	Side/bending load on a single-axis joint, or undersized	A rod eye is single-axis only — use a rod end where the joint tilts off-plane; size up if loaded hard
Thread strips	Insufficient engagement	Keep full thread engagement at the set length
Surface rust	Plating worn / wrong environment	Re-coat, or specify a corrosion-resistant option for wet/outdoor use

Single-axis only — the key limit: a rod eye has no spherical bearing, so it only pivots on its pin axis. If your geometry imposes any out-of-plane angle, the pin binds and the eye is loaded in bending — that’s when you move to a rod end or, for a fork interface, a clevis.

FAQ

Common Questions

What’s the difference between a rod eye and a rod end?

A rod eye is a solid forged eye with a threaded shank and no bearing — a simple single-axis pivot. A rod end has a spherical bearing for multi-axis articulation.

What does RER vs REL mean?

RER is the right-hand thread rod eye; REL is left-hand — used together for adjustable assemblies.

What material are rod eyes?

Carbon steel, zinc plated, forged for strength.

What sizes are available?

Bore/thread 1/2 x 1/2 to 5/8 x 5/8, 6 sizes — see the spec page for dimensions.

Can a rod eye replace a rod end?

Only where the joint moves on a single axis; if the linkage needs angular misalignment, use a rod end.

Factory Direct

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