Metso C Series Jaw Crushers — Jaw Plate Selection, Wear and Common Faults

1. The range and where each model sits

The C series runs from C80 up through C96, C100, C105, C106, C110, C116, C120, C125, C130, C140, C145, C150, C160 and C200, plus the C3054 for mobile installations. The number is the feed opening in centimetres; the higher the number, the larger the rock the machine will swallow and the heavier the wear parts become per set.

What matters for parts is not the model number but the pair: jaw die profile and feed size distribution. Two C125 machines in the same quarry can need different dies because one is fed by a controlled primary and the other takes whatever the excavator brings.

2. Jaw die profiles and what they are for

• Corrugated (standard). The default for quarry and mining work. The teeth grip the rock and stop it riding up in the chamber. Good compromise between life and throughput.
• Smooth. For recycling, slag and any feed where you need a tight setting and a flatter product. Less grip, so it needs a controlled feed.
• Multi-tooth / tall tooth. For slabby, elongated or reinforced material. The tall teeth bite into flat pieces that a standard profile lets slide.
• Quarry tooth. Deeper, more open profile for very large feed with high throughput.

Two rules from the shop floor:

1. The moving die and the fixed die must be a matched pair. Mixing a tall-tooth moving die with a flat fixed die produces a shearing action the frame was not designed for, and the die bolts take the load instead of the rock.

1. The die must be turned before it is worn out. The wear face is not flat; once the teeth are gone the crushing action changes from compression to grinding, throughput drops and power per tonne climbs. Turning at 60–70% wear doubles the life of a set rather than losing the second half.

3. Manganese grade

18% Mn (Mn18Cr2) is the working standard for granite, basalt and hard limestone. 22% Mn is worth the extra cost only when the feed is abrasive and the chamber is coarse — in a fine setting the higher manganese simply work-hardens less and the die wears by abrasion anyway.

The failure that looks like bad steel is usually a bad fit: a die that is not bedded flat on the jaw body flexes with every stroke, and no manganese grade survives that. We check the seating face and the bolt torque pattern before we discuss metallurgy.

4. Common faults

Toggle plate breaking

The toggle is the fuse of the machine. It is meant to fail before the frame does when something un-crushable goes through. If it breaks repeatedly the cause is upstream:

• Oversize rock entering the chamber (blasting pattern, grizzly gap)
• Toggle seats worn or not parallel — the plate is loaded on an edge
• A "stronger" plate fitted by someone improving the design; the next thing to fail is the pitman

Jaw die cracking at the toe

Almost always feed related. Slabs entering end-first put a bending load on the die the profile was not made for. Look at the feeding arrangement, the grizzly and the drop height before blaming the casting.

Bearing overheating

In a jaw crusher this is nearly always lubrication volume rather than grease quality: too little, too infrequently, or a grease that will not flow at ambient temperature in winter. Check the grease path and the relief port before replacing bearings.

Flywheel bolts loosening

Vibration, not torque. Retorque on a schedule and mark the bolts so movement is visible without a wrench.

Throughput dropping over a shift

The closed side setting has crept open, or the dies have worn into a shape that no longer grips. Measure the setting at the discharge, do not trust the indicator.

5. Maintenance that pays

• Check toggle seats and die bolts on the same interval as greasing.
• Record closed side setting every shift. Two minutes in a logbook shows a die wearing faster than it should weeks before a breakdown.
• Inspect cheek plates: a worn cheek plate lets material bypass the chamber and scour the frame.
• On C series machines with shim adjustment, keep the shim stack clean and dry — grit in the stack shows up as a setting that will not hold.

6. Matching parts to the machine

We work from the die part number, the machine serial and photographs of the worn die with a tape measure across the tooth depth. Metso revised die profiles over the production life of the C series; the same nominal profile can differ in tooth height between revisions, and the difference shows up as a die that will not seat.