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Helical Gear Blanks

High-precision turned gear blanks machined with strict tolerances ready for CNC gear hobbing processes.

Micron Precision Gear Blanks Sourcing

Srimukha Precision Technologies is a premier Tier-1 auto component manufacturer specializing in helical gears, blanks, spur gear configurations, and related engine transmission parts. We control the entire manufacturing lifecycle — from raw slug cutting and internal metallurgical forging to multi-axis CNC finishing.

Technical Specifications & Parameters

Every helical gear blank leaving our Ambattur plants is verified against strict dimensional, runout, and metallurgical guidelines:

Parameters

Specifications Achieved

Diameter range (Ø)

Up to 86.40 mm

Material Grades Sourced

Forged Steel Grade 8620 (SAE) / Alloy Steel 4140

Dimensional Tolerance

±0.010 mm (Class A+ OEM alignment)

Surface Finish (Roughness)

Ra 0.8 µm (Standard Ground)

Heat Treatment Compatibility

Normalized & Carburizing Grades (HRC 55-60)

Integrated Forging & CNC Machining Routing

To prevent runout and ensure balanced power transmission, our helical gear blanks undergo rigorous sequential machining:

  • Hot/Cold Forging: Srimukha's dedicated forging plants shape the initial blank structure, aligning the internal steel grain structure for maximum strength.
  • Double-Column CNC Turning: High-precision turning removes excess material, preparing smooth faces and centering bores.
  • Cylindrical Grinding: Holds diameter concentricity within 10 microns, eliminating setup errors.
  • Coordinate Measuring Machine (CMM) Verification: Real-time metrology lab checks ensure Cpk > 1.67 repeatability.

Runout Minimization

Axial and radial face runout is held within 5 microns, ensuring silent gear operation and high load capacity.

Material Certification

Each batch is shipped with chemical mapping reports and metallurgical micro-structure certifications.

Product Range Catalog

Click on any component below to view its full technical parameters and design specifications.

Solar Panel Motor Shafts

View Blueprints

NPD parts

Solar Panel Motor Shafts

Engineering Parameters

Material Grade

Tolerances Achieved

Surface Roughness

Heat Treatment

Process Routing

DIN CLASS 8-9

Power Tools Shafts

Gear Hobbing, Notching, Heat Treatment & Finish Grinding
SCM 415H / SCM420H / S45C
View Blueprints

NPD Parts

Power Tools Shafts

Engineering Parameters

Material Grade

SCM 415H / SCM420H / S45C

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

SQF – Case Carburising with Hot Oil Quenching / CNC

Process Routing

Gear Hobbing, Notching, Heat Treatment & Finish Grinding
DIN CLASS 8-9

Steering Worms

CNC Worm Whirling
SUM43
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Shafts & Worms

Steering Worms

Engineering Parameters

Material Grade

SUM43

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

~

Process Routing

CNC Worm Whirling
DIN CLASS 8-9

Window Regulator Motor Shafts

CNC Worm Milling (Double Spindle – Output – 300 Pcs/hr)
S45C
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Shafts & Worms

Window Regulator Motor Shafts

Engineering Parameters

Material Grade

S45C

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.10 Ra

Heat Treatment

~

Process Routing

CNC Worm Milling (Double Spindle – Output – 300 Pcs/hr)
Roundness (/o/) <1 micron, OD ±0.0025 mm

Window Regulator Motor Shafts

Motor Shaft Manufacturing SPM-LINE (Output – 750 Pcs/Hr)
SWRH62A
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Shafts & Worms

Window Regulator Motor Shafts

Engineering Parameters

Material Grade

SWRH62A

Tolerances Achieved

Roundness (/o/) <1 micron, OD ±0.0025 mm

Surface Roughness

0.10 Ra

Heat Treatment

~

Process Routing

Motor Shaft Manufacturing SPM-LINE (Output – 750 Pcs/Hr)
DIN CLASS 8-9

Automotive Tailgate Spindles

Tsugami Machining, Spline Rolling, CNC Worm Rolling
View Blueprints

EV Motor Parts

Automotive Tailgate Spindles

Engineering Parameters

Material Grade

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

~

Process Routing

Tsugami Machining, Spline Rolling, CNC Worm Rolling
±0.004 mm
,

BLDC – AC Compressor Shafts

Tsugami Machining, Slot Milling, OD Grinding
S45C
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EV Motor Parts & NPD parts

BLDC – AC Compressor Shafts

Engineering Parameters

Material Grade

S45C

Tolerances Achieved

±0.004 mm

Surface Roughness

0.30 Ra

Heat Treatment

Hardening & Tempering & Induction Hardening

Process Routing

Tsugami Machining, Slot Milling, OD Grinding
DIN CLASS 8-9

EV Motor Shafts

Cold Forging, CNC Machining, Gear Hobbing / Rack Rolling, Induction Hardening, OD Grinding
42CrMo4
View Blueprints

EV Motor Parts

EV Motor Shafts

Engineering Parameters

Material Grade

42CrMo4

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

Hardening & Tempering & Induction Hardening

Process Routing

Cold Forging, CNC Machining, Gear Hobbing / Rack Rolling, Induction Hardening, OD Grinding
DIN CLASS 8-9

Steering Pinion & Pinion Assist

Cold Forging, CNC Gear Hobbing (with p-point orientation), Rack Rolling, VMC Milling, Heat Treatment, CNC Gear Skiving
SCM420H
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Gears

Steering Pinion & Pinion Assist

Engineering Parameters

Material Grade

SCM420H

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

Speoridized Annealing/ Case Carburizing

Process Routing

Cold Forging, CNC Gear Hobbing (with p-point orientation), Rack Rolling, VMC Milling, Heat Treatment, CNC Gear Skiving
(±) 0.004 mm & Symmetry (⌯) within 0.10 mm

EV Hub Motor Shafts

Hot/Cold Forging, Drilling (VMC), Threading, Grinding
41Cr4
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EV Motor Parts

EV Hub Motor Shafts

Engineering Parameters

Material Grade

41Cr4

Tolerances Achieved

(±) 0.004 mm & Symmetry (⌯) within 0.10 mm

Surface Roughness

0.30 Ra

Heat Treatment

Hardening & Tempering

Process Routing

Hot/Cold Forging, Drilling (VMC), Threading, Grinding
DIN 6

4W – Differential Bevel Gears

Forging, Broaching, Hard Boring
SCM415H
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Gears

4W – Differential Bevel Gears

Engineering Parameters

Material Grade

SCM415H

Tolerances Achieved

DIN 6

Surface Roughness

~

Heat Treatment

Speoridized Annealing/ Case Carburizing

Process Routing

Forging, Broaching, Hard Boring
Critical External Profile

4W – Automotive Clutch Hubs

Cold Forging Including Dovetail, CNC Machining, CNC Induction Hardening & Phosphating
EN8D/EN19
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Gears

4W – Automotive Clutch Hubs

Engineering Parameters

Material Grade

EN8D/EN19

Tolerances Achieved

Critical External Profile

Surface Roughness

~

Heat Treatment

CNC Induction Hardening

Process Routing

Cold Forging Including Dovetail, CNC Machining, CNC Induction Hardening & Phosphating
±0.004 mm

4W – Starter Motor Carrier Shafts

Cold Forging, Spline Rack Rolling, Washer Pressing Hard Boring
SAE 8620H
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Shafts & Worms

4W – Starter Motor Carrier Shafts

Engineering Parameters

Material Grade

SAE 8620H

Tolerances Achieved

±0.004 mm

Surface Roughness

0.30 Ra

Heat Treatment

SQF – Case Carburising

Process Routing

Cold Forging, Spline Rack Rolling, Washer Pressing Hard Boring
±0.004 mm

4W-Starter Motor Output / Drive Shafts

Forging, Spline Rolling, CNC Centerless Grinding, CNC Boring, VMC Drilling, Bush Pressing
EN8D / S45C / SAE 1045
View Blueprints

Shafts & Worms

4W-Starter Motor Output / Drive Shafts

Engineering Parameters

Material Grade

EN8D / S45C / SAE 1045

Tolerances Achieved

±0.004 mm

Surface Roughness

0.30 Ra

Heat Treatment

CNC Induction Hardening

Process Routing

Forging, Spline Rolling, CNC Centerless Grinding, CNC Boring, VMC Drilling, Bush Pressing
NIL Air Gap

Alternator Rotor Assembly (Normal, VP & Internal Fan)

Shaft Mfg, Coil Winding, Claw Pole Pressing, Slip Ring Soldering, Varnishing, Rotor Turning, Dynamic Balancing
Child Parts
View Blueprints

EV Motor Parts

Alternator Rotor Assembly (Normal, VP & Internal Fan)

Engineering Parameters

Material Grade

Child Parts

Tolerances Achieved

NIL Air Gap

Surface Roughness

0.3 Ra

Heat Treatment

CNC Induction Hardening

Process Routing

Shaft Mfg, Coil Winding, Claw Pole Pressing, Slip Ring Soldering, Varnishing, Rotor Turning, Dynamic Balancing
DIN CLASS 5-6

2WH EV Transmission Gears

Hot / Cold Forging, CNC Gear Hobbing, ID Grinding, CNC Gear Grinding
16MnCrS5 / SCM415H
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Gears

2WH EV Transmission Gears

Engineering Parameters

Material Grade

16MnCrS5 / SCM415H

Tolerances Achieved

DIN CLASS 5-6

Surface Roughness

0.30 Ra

Heat Treatment

SQF – Case Carburising with Hot Oil Quenching

Process Routing

Hot / Cold Forging, CNC Gear Hobbing, ID Grinding, CNC Gear Grinding
DIN CLASS 8-9

EV Mid-Mount Motor Shaft

Forging, Rotor Slot Milling, Gear Hobbing, Grinding, Bush Pressing
42CrMo4
View Blueprints

EV Motor Parts

EV Mid-Mount Motor Shaft

Engineering Parameters

Material Grade

42CrMo4

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

CNC Induction Hardening

Process Routing

Forging, Rotor Slot Milling, Gear Hobbing, Grinding, Bush Pressing
Roundness [/O/] <1 micron, OD ±0.0025 mm

Blower Motor Armature Shafts (BLAC)

Sliding Head CNC Machining, OD Centerless Grinding (Imported), VMC Milling
S45C
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Shafts & Worms

Blower Motor Armature Shafts (BLAC)

Engineering Parameters

Material Grade

S45C

Tolerances Achieved

Roundness [/O/] <1 micron, OD ±0.0025 mm

Surface Roughness

0.30 Ra

Heat Treatment

N/A

Process Routing

Sliding Head CNC Machining, OD Centerless Grinding (Imported), VMC Milling
More Details →
Runout 0.2 mm

MDPS, C-EPS and EV Mid Mount Shafts, Pump Shafts as Forged

Horizontal 6-station Part Former (Cold Forging)
SWRCH45K (POSCO)
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Shafts & Worms

MDPS, C-EPS and EV Mid Mount Shafts, Pump Shafts as Forged

Engineering Parameters

Material Grade

SWRCH45K (POSCO)

Tolerances Achieved

Runout 0.2 mm

Surface Roughness

Heat Treatment

Spheroidized Annealing (85% with NIL Decarb)

Process Routing

Horizontal 6-station Part Former (Cold Forging)
Symmetry (/o/) within 0.05 mm

Column Assist Electric Power Steering (C-EPS) Shafts

Cold Forging with ID Profile, CNC Machining, VMC Milling
S45C
View Blueprints

Shafts & Worms

Column Assist Electric Power Steering (C-EPS) Shafts

Engineering Parameters

Material Grade

S45C

Tolerances Achieved

Symmetry (/o/) within 0.05 mm

Surface Roughness

0.4 Ra

Heat Treatment

Hardening & Tempering

Process Routing

Cold Forging with ID Profile, CNC Machining, VMC Milling
±0.004 mm

4W – Alternator Shafts & RS+PC Assembly

Muratec Machining, VMC Milling, CNC Centerless Grinding, Serration
CK45 / EN9
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Shafts & Worms

4W – Alternator Shafts & RS+PC Assembly

Engineering Parameters

Material Grade

CK45 / EN9

Tolerances Achieved

±0.004 mm

Surface Roughness

0.4 Ra

Heat Treatment

CNC Induction Hardening

Process Routing

Muratec Machining, VMC Milling, CNC Centerless Grinding, Serration
±0.004 mm

Motor Driven Power Steering (MDPS) Input & Output Shaft

Cold Forging, Machining, VMC Milling, Gear Hobbing, CNC Induction Hardening, ID Grinding, Torsion Bar Pressing, OD Grinding
SWRCH45K (POSCO)
View Blueprints

Shafts & Worms

Motor Driven Power Steering (MDPS) Input & Output Shaft

Engineering Parameters

Material Grade

SWRCH45K (POSCO)

Tolerances Achieved

±0.004 mm

Surface Roughness

0.30 Ra

Heat Treatment

CNC Induction Hardening

Process Routing

Cold Forging, Machining, VMC Milling, Gear Hobbing, CNC Induction Hardening, ID Grinding, Torsion Bar Pressing, OD Grinding
DIN CLASS 8-9

4W – Alternator & Armature Shaft

Gear Hobbing, Notching, Heat Treatment & Finish Grinding
SCM 415H / SCM420H / S45C
View Blueprints

Shafts & Worms

4W – Alternator & Armature Shaft

Engineering Parameters

Material Grade

SCM 415H / SCM420H / S45C

Tolerances Achieved

DIN CLASS 8-9

Surface Roughness

0.30 Ra

Heat Treatment

SQF – Case Carburising with Hot Oil Quenching / CNC Induction Hardening

Process Routing

Gear Hobbing, Notching, Heat Treatment & Finish Grinding
±0.005 mm

Slit Bush for Alternators

Grinding & Slitting
EN8M/S45C
View Blueprints

Shafts & Worms

Slit Bush for Alternators

Engineering Parameters

Material Grade

EN8M/S45C

Tolerances Achieved

±0.005 mm

Surface Roughness

Heat Treatment

SQF – Through Hardening

Process Routing

Grinding & Slitting

Product Catalog

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