How to Send an RFQ for a Custom Girth Gear: Drawings, Specifications, and Checklist for Buyers

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.

Quick Answer: What Should a Custom Girth Gear RFQ Include?

At a minimum, your RFQ should include:

1. Equipment type and application

2. Gear drawing or field measurements

3. Module or diametral pitch

4. Number of teeth

5. Pitch diameter, outside diameter, and face width

6. Number of segments and joint details

7. Material grade and heat-treatment requirements

8. Pinion data

9. Inspection and quality requirements

10. 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.

Why RFQ Quality Matters So Much for Large Girth Gears

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.

1. Start Your RFQ with the Equipment and Application Details

Before the supplier reviews drawings, they need to understand the actual service condition.

Include the following:

Equipment Information

• 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

Operating Information

• 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.

2. The Most Important Drawing Information to Include

The best RFQ always includes a clear drawing package. This may include assembly drawings, detailed manufacturing drawings, and site-marked field sketches.

Preferred Drawing Types

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

Essential Gear Drawing Data

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.

3. Segmented Girth Gear RFQs Need More Detail Than Full-Ring Gears

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.

4. Always Include Pinion Information in a Girth Gear RFQ

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.

5. Material, Heat Treatment, and Hardness Requirements Should Be Written Clearly

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.

6. Define Inspection, Testing, and Documentation Requirements Before Quotation

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:

Dimensional and Gear Accuracy Requirements

• 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 and NDT Requirements

• Material test certificate

• Chemical composition report

• Mechanical property report

• Hardness testing

• Ultrasonic testing (UT)

• Magnetic particle testing (MT)

• Dye penetrant testing (PT) where applicable

Commercial and QA Documents

• 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.

7. What to Do If You Do Not Have Original Drawings

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.

Useful Information for Reverse-Engineering Review

• 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

Critical Field Measurements to Collect

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.

8. Commercial Information Every RFQ Should Include

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.

9. Recommended RFQ Email Template for Buyers

Below is a practical RFQ format that can be used by procurement teams.

Sample RFQ Email

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:

1. technical comments,

2. quotation,

3. lead time,

4. inspection scope,

5. 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.

10. Buyer Checklist Before Sending the RFQ

Use this checklist internally before sending your inquiry.

A buyer who completes this checklist usually receives faster and more accurate quotations.

11. Common RFQ Mistakes That Cause Quotation Problems

Mistake 1: Sending Only a Photo and Asking for Price

Photos are useful, but they are not enough for technical quotation unless supported by dimensions and operating details.

Mistake 2: Not Confirming Tooth Data

Outside diameter alone cannot define gear geometry.

Mistake 3: Ignoring the Pinion

Quoting a girth gear without pinion information may create compatibility risk.

Mistake 4: Leaving Material “As Standard”

“As standard” means different things to different suppliers. Always define or request clarification.

Mistake 5: Not Mentioning Inspection Requirements Until After Quotation

Additional NDT, hardness testing, or third-party inspection affects both cost and lead time.

Mistake 6: Not Explaining the Real Project Situation

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.

12. What a Good Girth Gear Supplier Should Ask You

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.

Frequently Asked Questions

What is the minimum information needed to quote a custom girth gear?

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.

Can I get a quotation without the original OEM drawing?

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.

Why does the supplier need pinion information if I only want a girth gear?

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.

Should I specify material myself or ask the manufacturer to recommend it?

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.

What documents should I request with the order?

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.

Can Yile Machinery quote a custom segmented girth gear for a ball mill or rotary kiln?

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.

Request a Technical Review for Your Girth Gear RFQ

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.