1. Gajra Differential Gears is the largest manufacturer of automobile transmission gears in India, with 130,000 sq ft of machine shop area and 29,000 sq ft heat treatment facility and over 1000 employees. 2. The company produces spiral and hypoid gears, bevel gears, spider kit assemblies, and differential cages and housings. More than 50% of products are exported globally. 3. The gear manufacturing process involves operations like facing, centering, teeth cutting, heat treatment, grinding, and final inspection to produce precision-cut transmission gears for vehicles.

1. MEDI-CAPS INSTITUTE OF TECHNOLOGY & MANAGEMENT
Presentation on Industrial Training
At
Gajra Differential Gears Ltd. Dewas
Submitted to:
Mr. Jayesh Barve
Mechanical Department
MITM, Indore
Submitted by:
Nitesh Kumar

2. Company Profile
• Gajra Differential Gears was formed in 1991 to cater to the ever-growing
needs of the axle gear market for cars, trucks, and tractors.
• Currently Gajra Gears is the largest manufacturer of automobile
transmission gears in India.
• Comprise of 130,000 sq. ft. machine shop area and a 29,000 sq. ft. heat
treatment facility.
• It has a strength of over 1000 trained and committed employees and
offering a range of around 1700 gears for virtually every major brand of
truck, car, jeep, and tractor.
• ISO-9000, Better Manufacturing Practices.
• Best Manufacturing Practices - Six Sigma, TPM, TQM.

3. Products
Spiral and Hypoid Gears (Crown Wheel and Pinions)
 Module: 2.5 to 12 module
 Outside Diameter: 100mm to 500m
Bevel Gears
 Module: 1.5 to 10 module
 Outside Diameter: 30mm to 300m
Spider Kit Assemblies
Differential Cages and Housings

4. Export of Products
• More than 50% of the products manufactured at Gajra Gears are exported
across the globe.
• Precision-cut gears are exported to USA, Germany, Nigeria, Malaysia,
Thailand, UAE, Iran, Sri Lanka, Canada, Australia and China.
• The group's wide export range includes replacement gears for Mercedes,
Bedford, Hino, Fuso, Isuzu, Daihatsu, Mitsubishi, Magirus Deutz, Nissan,
Toyota, Willy's, Peykan, Tung Feng, Volvo, Eaton, Clark, Fuller, New
Process, Dana, Ford, ZF, Getrag, Massey Ferguson, International Harvester
and various others.

5. Flow Chart showing Gear
Manufacturing Processes
Packing
Inspection of Forging
and Blanks
Facing & Centering
CNC Turning
Drilling, Reaming,
Tapping
Keyway spline milling
or Hobbing
Teeth Cutting
Heat Treatment
Grinding
Final Inspection
After Heat Treatment
Inspection
Pre Heat Treatment
Inspection

6. What is a Differential
• Differential is a mechanical device made up of several gears including
crown wheel & tail pinion and Kit (Kit comprises of Bevel gear, Bevel
pinion gear and Spider gear).
• It is used to transmit power from drive shaft to drive wheels and allows
wheels on the same axle to rotate at different speeds.

7. At straight Road
At Turns

8. Differential Assembly
• Crown Wheel
• Tail Pinion
• Kit
– 2 Bevel gear
– 4 Bevel pinion
– Spider gear

9. Inspection of Forging & Blanks
• Forging inspection procedure:
– Dimensional checking
– Chemical analysis
– Metallurgical testing
• Machined blank inspection
– Crown wheel
– Tail pinion
– Bevel gear
– Bevel pinion
– Spider

10. Pre Teeth Cutting Operations
• Facing and Centering
• Drilling, Reaming & Tapping
• Keyways
• Splines
• Hobbing
• Broaching
• Milling

11. Cutting Tools
• According to tool strength
– HSS Steel or Carbide tip (Shiny silver color)
– Tin Coated (Gold color)

12. • According to blade insertion
– Ring type
– Inserted type

13. Teeth Cutting Section
• Crown Wheel
– 2 Cut cycle
• Roughing (GL-608 R)
• Finishing (GL-609 F)
• Tail pinion
– 3 Cut cycle
• Roughing(GL-116 R)
• Concave finishing (GL-118 outer blade)
• Convex finishing (GL-118 inner blade)
• Kit (Bevel, Bevel pinion, Spider)
– Single cut cycle (GL-104, GL-114)

14. Pre Heat Treatment Inspection
• Inspection of
– Dimensions as per drawing
• (Vernier & Dial guage)
– Bore diameter
– Threads (Plug guage)
– Splines (Full form guage)
– Surface finish
– Tolerances (Dial guage)
– Outness
– Correctness of crown wheel & tail pinion.

15. Heat Treatment
• Pre-washing
• Pre-heating
• Carburising (Temp. 890-930⁰C)
• Headening (Temp. 820-860⁰C)
• Quenching (Oil quenching)
• Post washing
• Tempering (Temp. 40-200⁰C)

16. Mr. K.K. Sinha
explaining us the working inside
The Heat Treatment Plant

18. After Heat Treatment Processes
1. Hydraulic Pressing

19. 2. Short Blasting & Peening

20. 3. Phosphating

21. After Heat Treatment Inspection
• Hardness test done on:
– Crown Wheel
– Tail Pinion
– Spider
– Bevel gears
• Study of grain structure
• Checking of dimensions and tolerances of the
different gears

22. Gear Finishing
• Shaving
– a cutter having the exact shape of the finished gear
tooth
– Only small amounts of material are removed by a
rolling and reciprocating action
• Grinding
• Honning
– Honing polishes the gear tooth surface and can be
used to correct minor errors in gear tooth geometry
• Lapping
– Done by preparing a paste of Honila oil and silica

23. Grinding Section
• Grinding is done on following machines:
– Jonship Main Cylinder Grinder
– Russian Spline Grinder
– Cylinder Grinder
– Landis Grinder

24. Final Inspection
• After Lapping Operation inspection of final
Crown-Wheel-Pinion on Testing Machine.
• Assembly of Kit assembly
• Final rolling of Differential housing

25. Packing of Gears
• Packing of following in boxes:
– C.W.P. Set
– Spider Kit assembly
– Housing
• Marking of crates for Export shipment
• Precautions during packing to avoid
– Rusting of gear set
– Dents & damage to gear
– Mis-matching of C.W.P. set

26. Packing of Gears