Bronze Outer eccentric bushing Symons 3ft cone crusher 2214-5321

Symons 3ft Outer Eccentric Bushing: 2214-5321 Replacement

The Outer Eccentric Bushing (P/N: 2214-5321) functions as the stationary bearing interface seated directly within the Main Frame of Symons 3ft cone crushers. It supports the rotating eccentric assembly. Because this component mates with the machine’s most expensive casting (the Main Frame), it serves a dual purpose: supporting radial crushing loads and acting as a sacrificial fuse to protect the frame bore from damage.

As one of the specialized crusher part suppliers, we manufacture this bushing using ASTM B505 C93700 High-Leaded Tin Bronze via Centrifugal Casting. Unlike cheaper sand-cast alternatives, our centrifugal process ensures a dense, porosity-free grain structure. This is critical for preventing fatigue cracking under the cyclic loading of hard rock crushing.

Metallurgy: Why We Upgrade to C93700

While some aftermarket suppliers use standard C93200 (Bearing Bronze), we specify C93700 for the Outer Bushing application. The difference lies in the lead content:

• 10% Lead vs. 7% Lead: The higher lead content in C93700 creates larger microscopic lubricant reservoirs. In older Symons crushers where lubrication pressure can fluctuate, this extra lead provides a “fail-safe” barrier, preventing the bronze from seizing (welding) to the steel eccentric or main frame during thermal spikes.
• Embeddability: C93700 is slightly softer (60-80 HBW), allowing silica dust and metal particles to embed into the bushing wall rather than scoring the mating steel surfaces.

Field Diagnosis: When to Replace

Visual inspection during liner changes can reveal the health of your crusher spares. Look for these indicators:

1. “Steps” in the Bore
Run a bore gauge or caliper down the ID. If you detect wear steps or ridges greater than 0.2mm, especially on the loaded side (counter-shaft side), the bushing geometry is compromised. This will cause the eccentric to tilt, destroying the gear mesh.

2. Keyway Deformation
Inspect the key slots on the outer flange. If the keys are loose or the slots are wallowed out, the bushing is vibrating within the main frame. This requires immediate replacement and likely the use of oversized keys or epoxy locking compound.

3. “Glitter” in Oil Analysis
A sudden spike in Copper (Cu) and Lead (Pb) in your oil report indicates active delamination. If Iron (Fe) is stable, the wear is confined to the bronze bushings.

Installation Best Practices: Cryogenic Fit

To ensure a tight fit without damaging the main frame bore, follow this procedure:

1. Bore Preparation: Hone the main frame bore to remove any fretting corrosion or burrs. Ensure the bore is round within 0.05mm.
2. Cryogenic Cooling: Do not use a hydraulic press to force the bushing in. Instead, cool the bushing to -50°C using Dry Ice or Liquid Nitrogen. This shrinks the diameter, allowing it to drop freely into the frame.
3. Key Alignment: Ensure the anti-rotation keys are perfectly aligned before the bushing warms up and expands.
4. Locking Compound: For older frames with slight ovality, apply a high-strength retaining compound to the OD to prevent micro-movements.

Compatibility

This part is a direct dimensional replacement for:

• Symons / Nordberg 3 Ft Standard Cone Crusher
• Symons / Nordberg 3 Ft Short Head Cone Crusher
• OEM Part Reference: 2214-5321

Performance Comparison

[Expert Tip] Before installing the new 2214-5321 bushing, check the vertical alignment of the Main Frame bore. If the frame bore is worn “bell-mouthed” (wider at the top), a standard bushing will work loose quickly. In such cases, contact us for an “Oversized OD” bushing solution to salvage your main frame without expensive machining.