Customized, fit-for-purpose mill parts and components that aim to improve the reliability of your machine. From a parts supplier to a full-service partner, Metso is here to support you, no matter the brand of your grinding mill.

Why choose Metso grinding mill parts?

OEM quality 

Applying the strictest standards and tolerances for guaranteed safety and reliability


Over 100 years of experience designing and supplying hard-working equipment and parts


With 150 distribution centers worldwide, we supply parts where and when you need them

End-to-end solutions

From original to third party to installation, we can support any equipment type

Render of Metso ball mill
Metso grinding mill spare parts

Metso has a proven history of designing, manufacturing, and servicing grinding mills and components. Our extensive range of global expertise allows us to be a flexible service partner for mill sustainability. We can fulfill standard and customized parts and component orders for: 

  • Heads
  • Shells
  • Gears and pinions
  • Main bearings
  • Trunnions
  • Trunnion liners
  • And more!
Grinding mill head

Material: cast ductile iron or cast steel
Design standard: Metso FEA
Segments: one, two, three, or four
Type: feed/discharge, fixed/floating, integral with the trunnion




Render of Metso grinding mill head
Render of Metso grinding mill shell
Grinding mill shell

Material: fabricated steel (welded)
Design standard: Metso FEA
Sections: integral, two or three cans
Segments: one, two, or three-piece




Gears and pinions

Material: cast ductile iron, cast steel, fabricated steel
Design standard: AGMA 6014 for open gearing
Section structure: T or Y design
Segments: two-piece or four-piece gears
Upgrade options: drop-in pinion assembly, gear guard and components, gear spray infrared monitoring system

Our gear and pinion services include:

Read more about our complete gear and pinion services here>>

Render of Metso grinding mill gear and pinion
Render of Metso grinding mill main bearing
Grinding mill main bearings

Material: fabricated steel (welded)
Type: hydrostatic or hydrodynamic (sleeve/pad), fixed or floating
Design standard: Metso FEA
Upgrade options: bearing insert (bronze, babbitt), seals, temperature monitoring systems, lubrication unit



Grinding mill trunnions

Material: cast ductile iron
Design standard: Metso FEA
Type: feed or discharge, fixed or floating



Render of Metso grinding mill trunnion
Render of Metso grinding mill trunnion liner
Grinding mill trunnion liners

Material: cast iron or fabricated steel
Wear material: vulcanized rubber lined or lifter and plate style replaceable bolt in
Type: feed or discharge

Learn more about Metso's grinding mill liners >


Specialized hardware

Metso provides all required hardware for grinding equipment assembly and operation. Large grinding equipment is typically split into multiple segments or cans to make their manufacturing and transport to a mine site feasible. The hardware to join these components consists of specialized bolts, nuts, washers, spacers, lubrication, torque wrenches and instrumentation, torque and elongation measuring equipment.

There are three categories of specialized hardware used in grinding mills:

  • Static bolts: Non-rotating bolts such as anchor bolts, bearing assembly bolts, etc.
  • Rotating bolts: Bolts that go through fatigue loading making their design and installation of utmost importance. Examples of these bolts include head-to-trunnion, head-to-head, head-to-shell, head-to-shell-to-gear, shell-to-shell, gear-to-gear, trunnion liner-to-trunnion, trommel-to-trunnion liner, etc.
  • Liner bolts: Bolts that rotate with the mill and function to attach mill liners to the grinding mill head and shell.

Critical fasteners

Fastening hardware such as bolts or studs used to secure mill structural components together must withstand the harsh forces of grinding mill operations. If a fastener failure occurs, a lack of spare components on site can make matters worse.

As an OEM, Metso has designed grinding mills for over 100 years. We know the importance of critical fastener applications and operating loads. When a hardware component fails, we stock various fastener sizes to minimize downtime and replenish critical parts when you need them most.

Read more >

High-quality hardware

Hardware ordered through Metso is of highest quality as every hardware order is accompanied by a proprietary Metso manufacturing and shipping specification. These specifications ensure that each bolt-nut-washer set is manufactured, quality checked and tested to requirements specified by our engineering professionals. They also ensure that hardware is packed and protected appropriately to avoid damage during transport.

Hardware can also be ordered with internal instrumentation. This helps to speed up bolt torqueing and mill assembly, and facilitate the verification of bolt preloads at specific intervals during the life of the mill.

Labratory testing

Bolt breakage may happen during mill operation due to mill overloads such as dropped-charge, use of defective or inferior bolts, contamination of mill flanges with slurry that causes bolt overloads, or improper installation resulting in bolt loosening. In such cases, Metso can provide laboratory testing of the broken bolts and make a root cause analysis. 

Turn-key services

Metso also provides turn-key services to remove broken bolts from threaded flanges and install replacement bolts. These services are fully supported with engineering.

When assembling a new mill or planning a major upgrade or refurbishment to an existing mill, getting input from a partner with OEM experience can make all the difference. It can help ensure each component of your mill from the gears and pinions to the last bolt in order to produce the results you need.

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Metso at MINExpo
Visit booth #12543 to discover how our solutions are empowering a responsible energy transition

Don't risk it – extend it

Metso grinding mills are designed and manufactured to the industry’s highest standards for longevity. Keep your critical mill components running for optimal performance with Metso's extended warranty program. The program expands basic coverage on heavy engineered replacement products for up to 120 months, expanding coverage from design and manufacturing to include installation, operation, maintenance and storage. Protect your investment with confidence. 

Learn more about Metso's extended warranty program >

Contender Series for non-Metso mills
In addition to supplying high-quality parts for Metso equipment, we also have a long history in servicing non-Metso machines, from grinding mills and crushers to conveyors and beyond. The Contender™ Series is our newest line of premium spare parts for non-Metso grinding mills. The line includes grinding mill heads, shells, gears and pinions, main bearings, trunnions, trunnion liners, and more for select machines.
For certain designated parts, additional enhancements have been made for increased safety, reliability and sustainability. Examples include correcting OEM design flaws and using improved materials for cost savings and longer life.
Contender Series grinding mill gear and pinion for non-Metso grinding mill
mill feed chute
Mill feed chute solution
For reduced downtime, improved safety and simplified access.
Polymer HSB System
The Polymer Hydrostatic Shoe Bearing (HSB) system significantly improves radial and axial bearing reliability and longevity.

Optimizing your mill parts

When was the last time you evaluated your parts supply? Metso is continuously upgrading designs and collaborating with customers to optimize the use of spare parts. Together we can explore new fabrication and material options to achieve your specific goals including:

  • Achieve better cost efficiencies
  • Increase production or capacity
  • Simplify the part replacement process
  • Reduce maintenance and downtime
  • Improve safety and increase sustainability

Metso experts are available to perform equipment and parts audits to uncover potential areas of improvement. Additionally, as operating conditions change, we can help you put a customized improvement plan in place.

Many brands, many applications


More for your grinding mill


From quick visual and vitals to detailed custom inspections for your mill and its key components.


With a team of over 1,500 global field service experts, we can carry out planned repairs and are extremely responsive in emergency situations.

Retrofits and upgrades

Your existing assets have the potential to take on significant improvements. We can support you from identifying retrofit options to implementation.

Life Cycle Services

Custom service packages focusing on parts supply and inventory, maintenance, process optimization and more.

Discover Metso's services for grinding mills >


Contact our experts to learn more!
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