Jaw crusher spare parts are the wear and mechanical parts that keep the jaw crusher — the heart of the primary crushing stage — running continuously and safely. The jaw crusher is the machine that takes the heaviest impacts in quarries, mines and construction and demolition waste recycling plants. Choosing its parts correctly therefore determines the efficiency of both the crusher and the whole plant behind it.
In this guide we introduce the parts of a jaw crusher one by one and look at each part’s function, signs of wear or failure, replacement criteria and stock recommendations. For the jaw crusher’s working principle, see our jaw crusher guide, and for our product range, our jaw crusher spare parts page.
Parts of a Jaw Crusher: Overview
| Part | Function | Group | Typical replacement trigger |
|---|---|---|---|
| Fixed jaw plate | The crushing surface attached to the frame | Wear | Tooth height and thickness |
| Moving jaw plate | The crushing surface attached to the pitman | Wear | Tooth height and thickness |
| Cheek plates | Protect the side surfaces of the crushing chamber | Wear | Thickness, approaching the frame |
| Toggle plate | Supports the pitman and breaks under overload, acting as a fuse | Mechanical / safety | Breakage, seat wear |
| Toggle seats | The seats in which the toggle plate sits | Mechanical | Wear, play |
| Pitman | Carries and moves the moving jaw | Mechanical | Cracks, bearing housing damage |
| Eccentric shaft | Drives the pitman | Mechanical | Bearing seat damage, cracks |
| Main and pitman bearings | Carry the eccentric shaft | Mechanical | Temperature, vibration, noise |
| Flywheel and drive pulley | Store energy and transmit power | Mechanical | Cracks, groove wear |
| Tension rods and springs | Pull the pitman towards the toggle plate | Mechanical | Broken spring, stretched rod |
| Adjusting wedges, shims or hydraulic adjustment | Set the closed side setting (CSS) | Mechanical | Wear, seizing |
| Jaw wedges and bolts | Secure the jaw plates | Fasteners | Check at every jaw change |
| Labyrinth rings and seals | Protect the bearings from dust | Sealing | Grease leakage, dust ingress |
Jaw Plates
Jaw plates are the most frequently replaced parts of a jaw crusher. They are usually cast from manganese steel (such as Mn18 or Mn22), and their surfaces harden under impact. The tooth profile (sharp tooth, wide tooth, flat) and thickness are chosen according to the material and target product.
- Turning: Symmetrical jaw plates can be turned over and reused when the lower part is worn; this considerably extends plate life.
- Replacement time: When tooth height falls below a certain proportion, crushing efficiency drops, the product becomes flaky and capacity decreases.
- Seating: The back of the jaw plate must seat fully on the frame and pitman surfaces; a gap behind the plate leads to cracking.
For more details, see our jaw plates guide.
Cheek Plates
Cheek plates protect the side walls of the crushing chamber. They wear together with the jaw plates; wear is concentrated particularly in the lower area. Worn cheek plates can lead to frame wear and expensive repairs. For details, see our cheek plates guide.
Toggle Plate and Seats
The toggle plate supports the lower end of the pitman, transferring the crushing force to the frame. It also works like the crusher’s fuse: when an uncrushable object enters the crushing chamber, the toggle plate breaks, protecting more expensive parts (pitman, eccentric shaft, frame).
- When the toggle plate breaks, the cause of the breakage (metal, overfeeding, wrong setting, fatigue) must always be investigated.
- When the toggle seats are worn, the plate does not seat properly; a new plate is also soon damaged.
- The toggle plate must be of the length and strength specific to the crusher model; fitting a stronger plate can eliminate the fuse function.
For details, see our toggle plate and seats guide.
Pitman and Eccentric Shaft
The pitman is a heavy cast or welded part that carries the moving jaw and converts the motion of the eccentric shaft into crushing motion. The eccentric shaft produces this motion with the eccentric section at the top of the pitman. Both parts are exposed to high impact and fatigue loads.
- The pitman body should be checked for cracks periodically (visually and, if necessary, by non-destructive testing).
- Wear or ovality in the bearing housings leads to early bearing failure.
- The bearing seats and keyways of the eccentric shaft should be checked.
For details, see our pitman guide and eccentric shaft and bearings guide.
Bearings
In jaw crushers, the eccentric shaft is usually carried on large spherical roller bearings: two main bearings in the frame and two pitman bearings in the pitman. Because these bearings work under heavy shock loads, the right type, the right internal clearance and correct mounting are critical. Greasing arrangements and labyrinth sealing are the main factors determining bearing life. For bearing selection and mounting, see our bearings guide.
Flywheels, Pulleys and Belts
Flywheels store energy during the crushing cycle and even out the load on the motor. One usually also serves as the drive pulley. Worn pulley grooves shorten belt life; loose clamping elements in the flywheel hub can cause serious damage. For details, see our flywheel guide and belt types guide.
Tension Rods, Springs and Setting System
Tension rods and springs pull the pitman towards the toggle plate, maintaining contact between the parts. Broken or fatigued springs can cause the toggle plate to leave its seat and the crusher to knock. The setting system (wedges, shims or hydraulics) sets the closed side setting. For details, see our tension rods and springs and setting system guides, and for the general properties of springs, our spring types guide.
Replacement Frequency and Stock Recommendations
| Part | Replacement frequency (general) | Stock recommendation |
|---|---|---|
| Jaw plates | Frequent (depends on rock and tonnage) | At least one set |
| Cheek plates | Medium | At least one set |
| Toggle plate | Event-based (breakage) and fatigue | Always in stock |
| Toggle seats | Medium | One set |
| Tension springs | Medium | One set |
| Bearings and seals | Infrequent | One set at critical plants |
| Eccentric shaft, pitman | Very infrequent | According to risk analysis |
| Jaw wedges and bolts | Check at every jaw change | Sufficient quantity |
Common Failures and Their Link to Parts
| Symptom | Possible part-related cause |
|---|---|
| Coarse, flaky product | Worn jaw plates, setting opened up |
| Knocking noise | Loose jaw plate, worn toggle seat, broken tension spring |
| Bearing overheating | Lack of lubrication, seal damage, bearing failure |
| Frequent toggle plate breakage | Tramp metal, overfeeding, seat wear, wrong plate |
| Belt slipping and heating | Worn pulley groove, wrong tension |
Frequently Asked Questions
What are the parts of a jaw crusher?
The main ones are the jaw plates, cheek plates, toggle plate and seats, pitman, eccentric shaft, bearings, flywheels, tension rods and springs, and the setting system.
When should a jaw plate be turned over?
When the teeth in the lower area are markedly worn, while the plate still retains its thickness. Turning too late reduces usable life.
Why does the toggle plate break?
It usually breaks because of an uncrushable metal object, excessive or incorrect feeding, worn seats or material fatigue. Breakage is a warning; the cause should be investigated.
Are the parts of mobile jaw crushers different?
The principle is the same; part dimensions are model-specific. The same part groups apply to mobile crushers. For details, see our mobile crusher maintenance guide.
Choosing a Jaw Plate Profile
| Profile | Characteristics | Suitable use |
|---|---|---|
| Sharp tooth | Good grip, aggressive crushing | Flat and slippery materials, some recycling applications |
| Standard (wide) tooth | General-purpose balance | Most quarries |
| Thick, heavy-duty tooth | More wear material | Very abrasive and hard rock |
| Corrugated or special profiles | Application-specific | Specific product and material targets |
The profile should be chosen according to feed size, rock type and target product. The wrong profile can lead to lost capacity or flaky product.
Factors Affecting Jaw Crusher Prices and Part Costs
- Crusher feed opening and capacity (part size and weight),
- Jaw plate material (Mn18, Mn22, reinforced),
- Machining precision of mechanical parts,
- Bearing type and brand,
- Order quantity and lead time.
When assessing part costs, wear cost per tonne and downtime cost should also be taken into account.
Jaw Plate Replacement Steps (Summary)
- The crusher is stopped, locked out and tagged; the crushing chamber is emptied.
- The jaw wedges and bolts are removed.
- The old jaw plates are removed with suitable lifting devices.
- The seating surfaces are cleaned and checked.
- The new plates are fitted and the wedges and bolts tightened to the manufacturer’s torque.
- The closed side setting is reset.
- The crusher is run empty, then under load; the bolts are checked again shortly afterwards.
Glossary
- CSS (closed side setting): The narrowest distance between the jaws.
- Pitman: The part that carries and moves the moving jaw.
- Toggle plate: The plate that supports the pitman and acts as a fuse.
- Cheek plate: The side wall protector of the crushing chamber.
- Flywheel: A heavy rotating mass that stores energy.
More Questions
Which is the most expensive part of a jaw crusher?
The frame, pitman and eccentric shaft are usually the most expensive parts; replacing wear parts on time and having the toggle plate work correctly are therefore important for protecting them.
How can jaw plate life be extended?
With even feeding, scalping out fines, timely turning and choosing a material suited to the rock.
Support from CSP Mühendislik
CSP Mühendislik supplies jaw plates, cheek plates, toggle plates and seats, tension springs, bearings and mechanical parts for jaw crushers, and provides service, maintenance and repair. You can find our parts guide for all crusher types on the crusher spare parts page and send your parts requirements via our jaw crusher spare parts page or WhatsApp line.
