Are matching module and tooth count sufficient to pair a pinion with a girth gear?

No. Also check pressure angle, helix angle and hand, profile shift, face width, accuracy class, centre distance, tooth modifications, materials, heat treatment and matching girth gear data.

Must the girth gear be inspected when replacing the pinion?

Yes. Inspect girth gear teeth, radial and face runout, contact pattern, backlash, centre distance, foundation and bearings to prevent poor contact between new and worn teeth.

SAG MILL DRIVE PINION

Drive Pinion

Heavy-duty drive component matched to the girth gear · Request a pinion, pinion shaft or complete assembly

Transmits drive torque to the mill girth gear. ANRANST provides gear data review, material and heat treatment assessment, manufacturing coordination, quality control and finished-part delivery.

Equipment SAG / AG mills with girth gear and pinion drives

Installation Position Drive output, at the girth gear mesh

Key performance requirements Tooth contact, bending strength, accuracy, shaft system stability and lubrication

Identification requirements Drawing reference, tooth data, matching girth gear, bearing interfaces, material and heat treatment

SAG mill pinion and girth gear mesh identification diagram. Manufacturing data must follow the matched gear drawings and installed equipment measurements.

Drive function

Transmit drive torque steadily to the girth gear

The pinion may be a separate gear, an integral pinion shaft or an assembly including bearing housings, couplings and lubrication interfaces. Define the supply scope before requesting a quotation.

Gear parameters cannot be inferred from outside diameter or tooth count alone. Confirm them using the matching girth gear drawing, centre distance, tooth data, helix hand, shaft and bearing interfaces.

Gear parameters Module or diametral pitch, tooth count, pressure angle, helix angle, helix hand, profile shift and face width

Shaft system interfaces Shaft diameters, shoulders, keys or splines, coupling, bearing and seal positions

Matching gear data Girth gear drawing reference, centre distance, backlash, contact pattern and tooth modification requirements

Supply scope Gear, pinion shaft, bearings, bearing housings, fasteners or complete assembly

Gear and shaft system performance

Control tooth flanks, roots, journals and gear contact separately

Assess manufacturing accuracy, installation accuracy, lubrication and foundation condition together for heavy-duty open gears.

Tooth contact

Check tooth profile, lead, modifications, roughness, contact pattern, pitting and scuffing risk.

Tooth root load capacity

Check root radii, surface quality, material cleanliness, heat treatment and fatigue cracks.

Shaft and bearings

Check journals, coaxiality, circular runout, fits, bearing clearance, seals and couplings.

Installed gear mesh

Check centre distance, backlash, radial and face runout, contact patterns, foundation and lubricant spray.

Materials and heat treatment

Select the drive gear alloy steel route according to dimensions, loads, tooth data and original design

Specify material grade, hardened layer and accuracy class against the applicable drawings and standards.

Quenched and tempered alloy steel For heavy-duty pinions originally designed for through-section quenching and tempering or tooth surface hardening. Control hardenability, core properties, hardness uniformity and residual stress.

Surface-hardened alloy steel For gears whose original design specifies carburizing, induction hardening or another surface hardening process. Confirm effective case depth, core toughness and grinding allowance.

Forging quality control Check the ingot and forging route, grain flow, forging ratio, heat treatment, mechanical properties and ultrasonic inspection.

Tooth finish machining Confirm hobbing, shaping, grinding or tooth modification processes, accuracy, roughness and inspection reports against the drawings and standards.

Confirm materials and heat treatment together with the matching girth gear, relative tooth hardness, lubrication and operating loads. Metso Grinding Mill Parts

Failure Diagnosis

Address pitting, scuffing, uneven loading, root cracks and bearing problems separately

Provide tooth photographs, contact patterns, vibration, temperature, lubrication and alignment records.

Observed condition	Priority checks	Improvement Options
Tooth pitting or spalling	Contact stress, hardness, roughness, uneven loading, lubrication and contamination	Restore contact and lubrication conditions, and check materials and heat treatment
Scuffing or abnormal scoring	Oil spray position, lubricant, temperature, sliding speed, backlash and tooth surface condition	Correct lubrication and gear mesh, and control surface quality
One-sided uneven wear	Tooth lead, centre distance, shaft parallelism, foundation, bearings and girth gear runout	Realign and check the matching girth gear
Tooth root cracks or broken teeth	Overload, impact, radii, machining defects, material cleanliness and heat treatment	Conduct nondestructive inspection and fracture analysis, and review loads and the manufacturing route
Bearing temperature rise or vibration	Journals, fits, clearance, lubrication, coaxiality, couplings and foundation	Restore shaft system accuracy and support condition

Drawing References and Inquiry Details

Identify the pinion by its matching girth gear and complete shaft system

Match confirmed OEM drawing references, third-party drawing references and spare part numbers to the equipment, gear pair and drawing revision.

Equipment and drive

OEM, full model, serial number, drive type, power, speed, operating conditions and modification history.

Drawing references and supply scope

Pinion drawing reference, shaft drawing reference, assembly number, third-party references, spare part numbers and supply scope.

Gear data

Tooth count, module or diametral pitch, pressure angle, helix angle, helix hand, profile shift, face width and accuracy.

Matching components and installation

Girth gear drawing reference, centre distance, backlash, contact pattern, runout, shaft alignment and foundation.

Shaft system interfaces

Shaft diameters, shoulders, keyways or splines, bearings, seals, couplings and lubrication.

Materials and inspection

Material standard, forging, heat treatment, hardness, case depth, mechanical properties, ultrasonic inspection and tooth inspection reports.

Related Equipment and Parts

Match the pinion, girth gear and materials to the OEM mill configuration

Drive gears are not interchangeable by equipment category. Confirm the complete gear pair data.

Girth Gear / Ring Gear Check matching tooth data, centre distance and contact. Alloy Steels for Drive Parts Review material, forging and heat treatment requirements. General Gears and Sprockets Explore drive components for different equipment types. SAG Mill Spare Parts System Return to equipment spare parts and RFQ requirements. Metso SAG Mill Equipment Identify the installed equipment by brand, series, model and drawing reference.

Request a SAG Drive Pinion Proposal and Quotation

Provide the model, drawing reference, gear data, matching girth gear, bearing and coupling interfaces, materials, heat treatment and site inspection records.

Send Details for a Quote

Manufacturing Services in China

From Technical Assessment to Finished-Part Delivery

Technical advice, supplier introductions, quality control and finished-part delivery.

Technical Advice

Review tooth data, matching components, shaft system, materials and failures.

Supplier Introductions

Coordinate heavy-duty gear forging, heat treatment, tooth machining and inspection.

Quality Control

Track forgings, heat treatment, tooth accuracy, nondestructive inspection, dimensions and reports.

Finished-Part Delivery

Arrange delivery of gears, shaft components, inspection records and installation documents according to the agreed supply scope.