Author: Lily Wang Publish Time: 2026-09-14 Origin: Yile Machinery
If you need a replacement girth gear for a ball mill, rotary kiln, SAG mill, dryer, or other large rotating equipment, the quality of your RFQ directly affects the quality of the quotation you receive.
A complete RFQ does more than help a supplier calculate price. It helps the manufacturer understand:
what the gear is used for,
whether the design is technically clear,
what inspection and material requirements apply,
how the new gear must match the existing pinion and drive system,
and whether the project involves a straight replacement, reverse engineering, or design optimization.
A poor RFQ creates delays, repeated technical questions, quotation errors, and higher project risk. A clear RFQ saves time and improves the chance of getting the right gear the first time.
This guide explains exactly what buyers should send when requesting a quotation for a custom girth gear, especially for ball mills, rotary kilns, SAG mills, and other heavy-duty open gear drives.
Yile Machinery manufactures custom girth gears, ring gears, pinions, and gear shafts for cement, mining, metallurgy, and heavy industrial equipment. We support OEM and replacement-part projects based on drawings, technical specifications, site measurements, and reverse-engineering review.
At a minimum, your RFQ should include:
Equipment type and application
Gear drawing or field measurements
Module or diametral pitch
Number of teeth
Pitch diameter, outside diameter, and face width
Number of segments and joint details
Material grade and heat-treatment requirements
Pinion data
Inspection and quality requirements
Quantity, delivery time, and destination port
If drawings are incomplete or unavailable, a quote may still be possible, but the supplier will need additional field measurements, photos, assembly information, and operating details.
A girth gear is not a standard commodity item. It is a large, high-value, application-specific transmission component. Errors in RFQ preparation can lead to:
Incorrect gear geometry
Poor fit at the mounting interface
Incompatible mesh with the existing pinion
Wrong material or hardness
Missing inspection scope
Delayed production because technical details must be clarified later
Installation problems during shutdown
Faster wear after startup
In large plants, the cost of one wrong dimension can be far greater than the cost difference between two suppliers.
This is especially true when the girth gear is part of a critical shutdown project. If the new gear arrives with missing dimensions, unclear bolt-hole locations, incorrect segment joints, or mismatched tooth data, the real cost will be measured in lost production time.
If you are still deciding what type of girth gear your equipment needs, see our related guide: How to Select a Girth Gear for Ball Mills and Rotary Kilns.
Before the supplier reviews drawings, they need to understand the actual service condition.
Include the following:
Equipment type: ball mill, SAG mill, rotary kiln, dryer, cooler, etc.
OEM or original equipment manufacturer
Equipment model number
Installation year if known
Whether the gear is an original spare, upgraded design, or emergency replacement
Whether the machine uses an open gear drive or enclosed gear arrangement
Main application industry: cement, mining, metallurgy, lime, chemical, etc.
Operating hours per day
Typical load condition
Drive power
Rotational speed
Shock loading or variable loading condition
Ambient temperature, dust, moisture, or corrosive environment where relevant
This information helps the manufacturer assess material, heat treatment, wear resistance, inspection level, and possible design risks.
The best RFQ always includes a clear drawing package. This may include assembly drawings, detailed manufacturing drawings, and site-marked field sketches.
Send any of the following if available:
Original OEM drawing
Customer-approved replacement drawing
Assembly drawing showing the girth gear position
Segment drawing for split gears
Pinion drawing
Foundation or mounting-interface drawing where relevant
2D PDF drawing
3D model in STEP, IGS, or similar format
The girth gear drawing should clearly show:
Module or diametral pitch
Number of teeth
Pressure angle
Helix angle if applicable
Pitch diameter
Outside diameter
Root diameter if specified
Face width
Rim thickness
Web or body structure
Bore or mounting diameter
Bolt-hole circle
Bolt-hole quantity and size
Segment count
Joint geometry
Match-marking requirement
Tooth direction for helical gears if applicable
Missing tooth data is one of the most common causes of quotation delay. A supplier may know the gear diameter, but without module and tooth count, the gear cannot be correctly manufactured.
Many girth gears for kilns and mills are manufactured as split or multi-segment assemblies to simplify machining, transport, export packing, and site installation.
If your project uses a segmented gear, your RFQ should also include:
Number of segments
Segment weight if known
Joint-face dimensions
Joint bolt pattern
Joint dowel or location method if used
Assembly sequence if required
Match marks or installation marks
Segment interchangeability requirements
Acceptable assembled runout after installation
A segmented girth gear is not only a tooth-cutting job. Joint design and assembly accuracy have a direct effect on runout, backlash variation, and contact pattern stability.
Yile Machinery manufactures heavy-duty girth gears and segmented ring gears for rotary kilns, ball mills, and other large open-gear equipment, including custom production for replacement and OEM projects.
A girth gear and pinion must work as a matched pair. Sending only the girth gear dimensions is often not enough, especially if the new gear will mesh with an existing pinion.
Include as much of the following as possible:
Pinion drawing
Pinion number of teeth
Module or diametral pitch
Pressure angle
Face width
Material grade
Heat-treatment condition
Hardness
Existing wear condition
Whether the pinion will be reused, repaired, or replaced
Shaft drawing if the pinion is mounted on an integral pinion shaft
If the existing pinion is worn, pitted, cracked, or misaligned, the supplier should know this before quoting. Otherwise, the buyer may install a new girth gear against a damaged pinion and shorten the service life of the new part.
If your concern is not only quotation but also gear mesh condition after installation, see our related article: Girth Gear and Pinion Alignment: A Complete Guide to Mesh Adjustment for Rotary Kilns and Ball Mills.
Do not assume the supplier will automatically know what steel grade or hardness you need based only on application name.
Your RFQ should state:
Required material grade
Equivalent international standard if relevant
Mechanical property requirements if specified
Heat-treatment condition
Surface hardness range if required
Core hardness or strength requirement if applicable
Whether material substitution is allowed only after buyer approval
Typical material options for large girth gears may include cast steel grades such as ZG45 or ZG42CrMo, or forged alloy steels where appropriate for the design.
If you are unsure which material is best, say so in the RFQ and ask the manufacturer to recommend options with explanation. A good technical quotation should clearly state:
proposed material,
proposed heat treatment,
expected hardness,
and why that route fits the application.
Many disputes happen not because the gear is unusable, but because the buyer and supplier never agreed on the inspection scope in advance.
Your RFQ should define the required quality-control documents and inspections, such as:
DIN, AGMA, ISO, or customer standard
Tooth profile accuracy
Tooth lead accuracy
Pitch tolerance
Radial runout
Face runout
Concentricity or coaxiality requirements if applicable
Material test certificate
Chemical composition report
Mechanical property report
Hardness testing
Ultrasonic testing (UT)
Magnetic particle testing (MT)
Dye penetrant testing (PT) where applicable
Final dimensional inspection report
Heat-treatment report
Segment assembly marks
Packing list
Shipping marks
Third-party inspection if required
Witness inspection points if required by the buyer
Yile Machinery's gear pages state in-house gear cutting, machining, dimensional inspection, and non-destructive testing support for heavy-duty gears and pinions, which is exactly the type of information serious buyers should confirm before placing an order.
This is very common in older cement plants, legacy mining lines, and imported equipment where the original spare-parts documentation is incomplete or unavailable.
A quotation may still be possible if you provide enough replacement information.
Photos of the existing girth gear
Photos of damaged teeth and segment joints
Photos of installation location on the kiln or mill
Field measurements
Old inspection records
OEM nameplate information
Existing pinion measurements
Sample tooth profile tracing if available
Material certificate of the old gear if available
Previous supplier drawing, even if outdated
At a minimum, try to collect:
Outside diameter
Face width
Number of teeth
Segment quantity
Tooth thickness if measured
Bolt-hole circle diameter
Bolt-hole diameter
Joint dimensions
Mounting-surface dimensions
Pinion tooth count
Backlash reading if available
Radial runout if available
If your existing gear is already damaged and you are not sure whether replacement is necessary, you may also find this guide useful: Girth Gear Repair or Replacement? How to Make the Right Decision for Rotary Kilns and Ball Mills.
Even a technically complete RFQ can still cause delays if it is missing basic commercial information.
Include the following:
Quantity required
Whether this is a one-time replacement or repeated order
Required delivery date
Shutdown date if applicable
Destination country
Destination seaport or inland delivery location
Preferred trade term: EXW, FOB, CFR, CIF, etc.
Packing requirement
Surface protection or anti-rust requirement
Whether wooden cases, steel frames, or seaworthy packing are needed
Buyer company name and contact person
Preferred quotation currency
The earlier the supplier understands delivery timing and export requirements, the more realistic the quotation and production schedule will be.
Below is a practical RFQ format that can be used by procurement teams.
Subject: RFQ for Custom Segmented Girth Gear for Ball Mill
Dear Sales and Engineering Team,
We are looking for a quotation for a custom replacement girth gear for our ball mill application.
Equipment Information
Equipment type: Ball Mill
Application: Cement grinding
OEM/model: [insert if known]
Installation location: [country/plant]
Gear Information
Gear type: Segmented girth gear
Number of segments: [insert]
Module: [insert]
Number of teeth: [insert]
Outside diameter: [insert]
Face width: [insert]
Material required: [insert or ask for recommendation]
Heat treatment/hardness: [insert if known]
Pinion Information
Existing pinion will be [reused/replaced]
Pinion teeth: [insert if known]
Pinion drawing attached: [yes/no]
Inspection and Documentation
Required: MTC, hardness report, UT/MT report, dimensional inspection report
Standard: [DIN/AGMA/ISO/customer standard]
Commercial Information
Quantity: [insert]
Required delivery time: [insert]
Destination port: [insert]
Packing requirement: [insert]
Please find attached our available drawings, photos, and field measurements for your review. Kindly provide:
technical comments,
quotation,
lead time,
inspection scope,
and any additional information required from our side.
Best regards,
[Name]
[Company]
[Email / Phone]
This kind of structure improves communication quality and reduces repeated clarification emails.
Use this checklist internally before sending your inquiry.
Item |
Confirmed? |
Equipment type and application identified |
Yes / No |
Original drawing attached if available |
Yes / No |
Module or diametral pitch confirmed |
Yes / No |
Number of teeth confirmed |
Yes / No |
Outside diameter and face width confirmed |
Yes / No |
Segment quantity and joint details included |
Yes / No |
Mounting-hole pattern attached |
Yes / No |
Material and hardness requirements defined |
Yes / No |
Pinion information attached |
Yes / No |
Inspection standard defined |
Yes / No |
Required reports listed |
Yes / No |
Quantity and delivery date stated |
Yes / No |
Destination port and packing requirements included |
Yes / No |
Photos of existing gear attached |
Yes / No |
Field measurements attached if drawings are incomplete |
Yes / No |
A buyer who completes this checklist usually receives faster and more accurate quotations.
Photos are useful, but they are not enough for technical quotation unless supported by dimensions and operating details.
Outside diameter alone cannot define gear geometry.
Quoting a girth gear without pinion information may create compatibility risk.
“As standard” means different things to different suppliers. Always define or request clarification.
Additional NDT, hardness testing, or third-party inspection affects both cost and lead time.
The supplier should know whether this is:
an emergency shutdown replacement,
a planned annual maintenance project,
a reverse-engineering job,
or a new OEM design.
These situations require different engineering and scheduling approaches.
A capable manufacturer should not immediately give a price based only on rough dimensions. A serious engineering supplier will usually ask follow-up questions such as:
Is the existing pinion being reused?
What caused the old gear to fail?
What standard should the gear be manufactured to?
What runout and backlash conditions exist on site?
Is the gear segmented or one-piece?
Can the buyer provide drawings of the mounting interface?
Are there any restrictions on transport size or packing?
Is there a fixed shutdown date?
These questions are a good sign. They show the supplier is trying to reduce project risk rather than only issue a fast price.
You can also review our broader heavy-duty industrial product range if your project also involves pinions, shafts, tyres, rollers, trunnion bearings, or other related replacement parts.
At a minimum, most suppliers need equipment type, gear application, module or diametral pitch, number of teeth, outside diameter, face width, segment quantity, and delivery destination. However, a more accurate quote usually also requires pinion data, material requirements, and mounting details.
In many cases, yes. A supplier can often begin a reverse-engineering review based on photos, field measurements, segment details, old records, and pinion information. Final production should proceed only after technical details are confirmed.
Because the new girth gear must mesh correctly with the existing pinion. If the pinion is worn, has different geometry, or is near the end of service life, that affects the quotation recommendation and the long-term reliability of the new gear.
If your plant standard or OEM requirement is already clear, specify it in the RFQ. If not, ask the manufacturer to recommend a suitable material and heat-treatment route based on the application and service condition. A professional supplier should explain the reasoning behind the recommendation.
Typical documents include a material test certificate, heat-treatment report, hardness report, UT/MT report, final dimensional inspection report, and packing list. For critical projects, buyers may also request third-party inspection and gear measurement records.
Yes. Yile Machinery manufactures custom girth gears, pinions, and related heavy-duty transmission parts for ball mills, rotary kilns, SAG mills, crushers, and other industrial equipment. We support quotation and production based on customer drawings, specifications, and reverse-engineering review when needed.
If you are preparing an inquiry for a custom replacement girth gear, sending complete technical information from the beginning will help your project move faster and with lower risk.
To receive a quotation, please send:
Gear drawing or field sketch
Module, number of teeth, and face width
Outside diameter and segment quantity
Joint and mounting-hole details
Material and hardness requirements
Pinion drawing or pinion data if available
Inspection and documentation requirements
Quantity, required delivery date, and destination port
Photos of the existing gear and installation area
Yile Machinery can support custom manufacturing for girth gears, pinions, shafts, and other heavy-duty machinery parts used in cement, mining, and other demanding industrial applications. You can also browse our ball mill gear solutions, explore our full products page, or read more technical articles in our blog center.
