Novelty Structures offers Contract Gear Manufacturing of
Helical Gears, Spur Gears, Bevel Gears, Gear Rack and
Worm Gears
Contract Gear Fabrication Service
Looking for high-quality, precision-engineered contract gear fabrication services? Novelty Structures specializes in manufacturing custom gears with its extensive CNC Machining, Milling and Turning capabilities to ensure high performance and durability. With state-of-the-art machinery and a team of skilled engineers, we provide a full range of gear solutions, including spur gears, helical gears, worm gears, and bevel gears.
Whether you need prototypes, small batches, or large-scale production, we guarantee precise tolerances, exceptional material quality, and on-time delivery to keep your operations running smoothly.
Partner with us for unmatched expertise and reliability in gear fabrication. We work closely with several industries to deliver gears that meet the highest industry standards. Our commitment to quality control, cost efficiency, and cutting-edge technology ensures that every gear we produce enhances the performance and longevity of your machinery.
Gear Manufacturing Operations
Gear Milling
- Gear milling is a cost-effective, flexible method for creating various gear types like spur, helical, bevel gears, racks, splines, and ratchets.
- It uses circular, disc-type, and end-mill cutters, with the cutter shape conforming to the gear tooth space.
- Each tooth is individually cut, with the process repeating for each tooth.
- Suitable for small-volume, low-precision gear production.
- Different gears require specific milling cutters, which are less expensive than other types.
- Frequently used for low-speed machinery and gears where minor deviations are not critical.
Gear Broaching
- Broaching is a high-precision machining process for cylindrical gears, offering excellent geometric accuracy and surface finish.
- Broaching involves removing metal with a broach, a multi-toothed tool
- It also involves uniform tooth forms and robust surfaces to handle broaching pressure.
- It is suitable for external and internal spur and helical gears, racks, splines, and sector gears.
- Broaching requires a specific broach for each gear size, making it ideal for large-scale production.
- It’s effective for both small gears in a single pass and large gears using surface-type broaches.
Gear Cutting
- A gear shaper is a machine tool that uses linear motion for cutting,
- Primarily employed in the manufacturing of simpler, lower quality gears like spur gears, splines, and clutch teeth.
- It’s effective for mass production due to its ability to economically cut large quantities with a tool whose cutting edge matches the tooth space shape.
- The process involves reciprocating the tool parallel to the gear blank’s center axis, cutting one tooth space at a time, and rotating the gear blank to cut successive teeth.
They excel at producing simpler gears like spur gears and splines, they are less suited for high-precision or complex types,
Gear Hobbing
- Gear hobbing is a process for generating gear teeth using a rotating cutter called a hob, resembling a worm gear with multiple flutes for cutting.
- It’s used for making spur, helical, worm gears, and splines in various materials.
- It isn’t suitable for bevel or internal gears.
- Hobbing is economical but may require additional finishing for high precision.
The process includes;
- Axial hobbing (for spur and helical gears)
- Radial hobbing (for worm wheels)
- Tangential hobbing,
each differing in the direction of the hob’s feed relative to the gear blank.
Gear Planing
- Gear planning is a traditional method for making spur and helical gears
It involves a reciprocating rack-type cutter working against a gear blank.
There are two main types;
- The Sunderland process (horizontal gear blank axis, parallel cutter motion) and
- The Maag process (vertical gear blank axis, adjustable cutter in any vertical angle and direction).
While Sunderland uses a practical-length cutter rack, Maag involves periodic repositioning of the rack.
Planing is generally less precise than shaping and hobbing due to potential geometry errors from repositioning.
Classification of Gears
This category includes spur gears, helical gears, and rack and pinion gears. These gears are characterized by;
- Their simple design and manufacturing
- High efficiency, easy assembly
- Excellent precision
- High wear
- Noisy operation.
They are commonly used in
- Automotive transmission,
- Industrial drives
- Machine tools
- Motors and pumps
- Agriculture equipment
- Scientific instruments
- Electronic devices,
- Large mills
Straight bevel gears and spiral bevel gears are an example for these kind of gears.
The shaft axes intersect in this configuration, often at a right angle. Straight bevel gears are simple to produce and widely used, whereas spiral bevel gears are employed for higher-speed applications due to their smoother and quieter operation.
This category includes;
- Worm gears: Worm gears are used for high-ratio speed reduction in limited spaces and are known for their quiet and smooth operation despite low transmission efficiency.
- Hypoid gears : Hypoid gears are similar to spiral bevel gears but with hyperboloid pitch surfaces and offset pinion axes, leading to improved smoothness and lower noise
- Cross-helical (screw) gears : Cross-helical gears are employed in light-load applications and allow a wide range of speed ratios without changing gear size and centre distance
Gear Materials
- Cast Iron: Includes gray, ductile, and malleable cast iron. Known for low cost, good machinability, excellent noise-damping characteristics, and superior performance under dynamic conditions. Gray cast iron is not suited for gears subjected to shock loads due to low shock resistance, while ductile iron offers good impact strength and fatigue strength
- Steel: Several types of steel are used in gear manufacturing:
-
- Low-carbon steels (e.g., AISI 1010, 1015, 1020, 1021, 1022, 1025)
- Medium-carbon steels (e.g., AISI 1035, 1040, 1045)
- High-carbon steel (e.g., AISI 1060)
- Carburizing steel, through-hardening gear steels (e.g., AISI 8620, 20MnCr5, SAE5120)
- Alloy steels like chrome-molybdenum alloy steel (AISI 4140)
- Stainless Steels: Used for gears exposed to high temperature and corrosive environments. Types include;
- austenitic (e.g., 303, 304, 316),
- ferritic (e.g., type 430),
- martensitic (e.g., type 440 C),
- precipitation hardening (e.g., 17-4PH, 17-7PH) stainless steels
- Materials such as copper, brass, bronze, aluminium, and magnesium are used for machined, die-cast, and formed gears
- High-strength wrought aluminium alloys (e.g., 2024, 6061, 7075) and aluminium silicon alloys (e.g., A360, 383, 384, 413) are used for machined and die-cast gears
- Magnesium alloys (e.g., ASTM AZ91A, AZ91B, AM60, AS41) are used in lightweight die-casted gears for low-load applications
Plastics, including thermoplastics and thermosets, are extensively used in gear manufacturing. Examples include ;
- Nylon,
- Polyacetal
- Polyamide
- Polycarbonate
- Polyurethane
- Phenolic laminates
- Polytetrafluoroethylene (Teflon).
They are preferred for applications requiring light weight, smooth and quiet operation, and resistance to wear and corrosion
Types of Gears
Chain Gears (Sprockets)
Chain gears, or sprockets, are designed to engage with chains to transmit rotary motion and power in systems like conveyor belts, bicycles, and industrial machinery. They are widely used in systems where flexibility and precise torque transmission are needed.
Basic Features
- Tooth Profile: Designed to fit chain rollers precisely, minimizing wear and maximizing efficiency.
Load Capacity: High due to their ability to handle tensile forces.
Flexibility: Suitable for long-distance power transmission
Material Characteristics
Common Materials: Carbon steel, stainless steel, and hardened alloys.
Hardening: Teeth are often hardened (induction hardening or case hardening) for wear resistance.
Corrosion Resistance: Stainless steel or coatings (e.g., zinc, nickel) for harsh environments.
Fabrication Methods
TIG Welding: Preferred for its precision and control.
Ferrite Control: Appropriate ferrite content prevents cracking.
- Back-Purging: Using inert gas to protect the weld’s backside from oxidation.
Spur Gears
Spur gears transfer motion and power between parallel shafts, offering high efficiency in torque and speed transmission.
Basic Features
Teeth Orientation: Straight and parallel to the gear axis.
Contact Ratio: One tooth in contact at a time, leading to high efficiency but increased noise at high speeds.
Simplicity: Straightforward design for low-cost production.
Material Characteristics
Common Materials: Hardened steel, cast iron, aluminium for lightweight applications, and plastic for noise reduction.
Hardening: Heat treatments like carburizing or nitriding to resist wear under heavy loads.
- Heat Treatment : Apply processes like carburizing or induction hardening to increase hardness and durability.
Fabrication Methods
Hobbing: The most common method for cutting teeth.
Shaping: Used for internal gears or gears with unique profiles.
Grinding: Applied to hardened gears for high precision and surface finish.
Helical Gears
Helical gears transmit motion and power between parallel or angled shafts, offering smoother and quieter operation than spur gears.
Basic Features
Teeth Orientation: Angled teeth create a gradual engagement.
Load Capacity: Higher than spur gears due to increased tooth engagement.
Axial Thrust: Side forces require the use of thrust bearings or axial support.
Material Characteristics
Common Materials: Alloy steel for strength, stainless steel for corrosion resistance, and ductile iron for cost-effectiveness.
Surface Hardening: Induction or case hardening to withstand high surface stresses.
Lubrication Requirements: Essential to reduce friction and wear caused by sliding contact.
Fabrication Methods
Hobbing and Milling: For cutting helical teeth at precise angles.
Gear Grinding: Ensures surface smoothness and accuracy after hardening.
Heat Treatment: Carburizing to enhance strength
CNC Machining: Used for complex tooth profiles.
Worm Gears
Worm gears are used for high torque reduction in compact spaces and self-locking systems where back-driving needs to be prevented.
Basic Features
Gear Pairing: Consists of a worm (screw) and a worm wheel.
Speed Reduction: Capable of high reduction ratios (e.g., 20:1 or greater).
Self-Locking: Depending on the lead angle, worm gears resist reverse motion.
Material Characteristics
Common Materials: Hardened steel for the worm, bronze or brass for the worm wheel (reduces friction and prevents galling).
Friction Reduction: Materials with low friction coefficients are used to handle sliding motion.
Heat Treatment: Processes like carburizing or induction hardening are applied to increase durability and wear resistance
Fabrication Methods
- Casting: Often used for large worm wheels.
Thread Milling: Used to cut the worm profile.
Hobbing or Shaping: For worm wheel teeth.
Surface Coating: Phosphating or nitriding for improved wear resistance.
Herringbone Gears
Herringbone gears transfer power between parallel shafts with high load capacities and minimal noise or vibration.
Basic Features
Double Helical Design: Combines two opposing helical gears to cancel out axial thrust.
High Load Distribution: Multiple teeth are engaged simultaneously for superior load handling.
Vibration Reduction: Smooth operation even at high loads and speeds.
Material Characteristics
Common Materials: Hardened alloy steel for durability, stainless steel for corrosion resistance.
Heat Treatment: Induction hardening for enhanced wear resistance under heavy loads.
Fatigue Strength: Materials must endure cyclic loading over long periods.
Fabrication Methods
- CNC Machining: Ensures precision in the complex V-shaped tooth profile.
Gear Grinding: Applied to hardened gears for smooth surfaces and minimal backlash.
Shaping: Used for specific geometries in larger gears.
Casting: For large-scale gears in heavy-duty applications.
Rack Gears
Rack and pinion gears convert rotary motion into linear motion, commonly used in steering systems, lifting mechanisms, and CNC machines.
Basic Features
Linear Motion: The rack is a straight gear, and the pinion is a circular gear that engages it.
High Precision: Requires consistent tooth geometry for accurate motion.
Variable Length: Racks can be extended by aligning multiple sections.
Material Characteristics
Common Materials: Carbon steel, stainless steel for corrosion resistance, and engineering plastics for lightweight applications.
Wear Resistance: Hardening treatments or surface coatings are applied for durability.
Lubrication Requirements: Essential to reduce wear and ensure smooth movement.
Fabrication Methods
Gear Milling: Used for both rack teeth and pinion cutting.
Shaping: Common for racks with straight profiles.
Grinding: Ensures precision and minimal backlash in high-accuracy applications.
Heat Treatment: Induction hardening for racks exposed to heavy loads.
Materials used in Gear Fabrication
Alloy Steel Gears
- Used in aerospace applications where high load-carrying capacity and precision are vital.
- Found in power generation equipment like turbines and windmills.
Essential for cranes and heavy-load machinery in construction and bulk material handling.
Stainless Steel Gears
- Ideal for marine equipment such as winches, hoists, and ship propulsion systems due to its rust resistance.
Used in food and pharmaceutical processing equipment where hygiene and corrosion are critical.
Common in medical devices for surgical instruments and hospital machinery
Cast Iron Gears
- Preferred in compressors and pumps for its vibration-damping properties.
- Used in printing presses and other low-speed industrial applications where cost is a priority.
- Found in agricultural tools such as plows and seeders due to its robustness and ease of casting.
Aluminium Gears
Lightweight gears in aerospace systems such as satellites, drones.
- Essential for robotic systems where weight reduction ensures faster and more efficient movement.
- Popular in electric vehicles, where lightweight gears improve energy efficiency and performance.
Plastic Gears
- Often used in toys, appliances, and consumer electronics
- Found in office equipment like printers and copiers, where low cost and quiet operation are important.
Applied in medical and food machinery due to their ability to meet hygienic standards.
Gear Finishing Options
Purpose:
- Achieve precise dimensions, surface finish, and tight tolerances.
- Minimize surface roughness for smoother operation and reduced noise.
- Remove distortions caused by heat treatment.
Process:
- Uses abrasive wheels or grinders to remove material.
- Common for hardened steel gears or those requiring high precision.
Benefits:
- Produces surface finishes as fine as 0.1–0.2 µm.
- Ensures accurate gear profiles, reducing backlash.
- Ideal for high-performance gears (e.g., automotive or aerospace).
Applications:
- Helical gears, spur gears, and worm gears requiring precision.
- Used in applications with high speeds and loads, such as transmissions.
Purpose:
- Further smooth the surface to reduce friction and wear.
- Improve the aesthetic appeal of gears.
- Enhance fatigue strength by eliminating micro-surface imperfections.
Process:
- Uses abrasives, polishing compounds, or buffing wheels.
- Can be manual, automated, or robotic for consistency.
Benefits:
- Reduces surface roughness to below 0.05 µm.
- Ideal for gears in high-efficiency systems.
- Enhances corrosion resistance when combined with coatings.
Applications:
- Gears in precision instruments, robotics, and high-speed machines.
Purpose:
- Improve fatigue resistance and lifespan by inducing compressive surface stresses.
- Reduce the risk of cracks and failures under cyclic loads.
- Refine surface texture to enhance gear durability.
Process:
- Bombards the gear surface with high-velocity steel, ceramic, or glass beads.
- Deforms the surface microscopically, creating beneficial residual stresses.
Benefits:
- Increases wear and impact resistance.
- Enhances gear performance in high-stress environments.
- Reduces distortion from heat treatment.
Applications:
- Automotive and aerospace gears subjected to repetitive stress.
- Heavy-duty gears in construction and mining equipment.
Purpose:
- Improve gear accuracy by fine-tuning tooth surface profiles.
- Enhance contact patterns between meshing gears.
- Minimize noise and vibration in operation.
Process:
- Uses abrasive pastes or slurries applied between meshing gear pairs.
- Typically done on hardened gears to ensure tight tolerances.
Benefits:
- Provides a smooth surface finish (~0.2–0.5 µm).
- Improves gear engagement and operational smoothness.
- Can correct minor errors in tooth alignment or profile.
Applications:
- High-precision gears like hypoid or bevel gears in automotive differentials.
- Aerospace components and industrial machinery.
Purpose:
- Strengthen the gear’s surface for wear resistance and toughness.
- Remove scaling or discoloration caused by heat treatment processes.
Processes:
- Case Hardening (Carburizing, Nitriding): Hardens the surface while maintaining a ductile core.
- Post-Treatment Finishing: Includes grinding or polishing to restore surface quality.
Benefits:
- Ensures consistent hardness across the gear teeth.
- Reduces material brittleness from thermal stresses.
Applications:
- Hardened steel gears in heavy machinery and gearboxes.
- Automotive and aerospace components requiring durability.
Purpose:
- Enhance corrosion resistance, wear resistance, and aesthetic properties.
- Improve surface hardness for better performance.
Common Coatings:
- Electroless Nickel Plating: Provides a uniform, corrosion-resistant coating.
- Zinc Plating: Protects against rust in outdoor or humid environments.
- Phosphate Coating: Enhances wear resistance and lubrication retention.
- PVD (Physical Vapor Deposition): Deposits hard coatings like titanium nitride (TiN) for wear resistance.
Benefits:
- Prevents rust, oxidation, and chemical wear.
- Enhances gear longevity in harsh environments.
Applications:
- Outdoor machinery, marine gears, and medical equipment.
- High-performance gears in aerospace and defense.
Purpose:
- Improve tooth accuracy and surface finish.
- Remove burrs and minor imperfections left after machining.
Process:
- A honing tool with abrasive materials is passed along the gear teeth.
- Involves low-pressure abrasive action.
Benefits:
- Improves surface roughness to 0.2–0.4 µm.
- Ensures tighter tolerances and smoother meshing.
- Eliminates minor distortions caused by hardening processes.
Applications:
- Automotive gears and powertrain components.
- Industrial equipment requiring smooth, quiet operation.
Comparison of Gear Materials
| Material | Strength | Corrosion Resistance | Wear Resistance | Weight | Cost | Application |
|---|---|---|---|---|---|---|
| Carbon Steel | High | Moderate | High | Heavy | Low | Gears in industrial machinery, automotive transmissions, agricultural equipment, mining machinery, and construction equipment. |
| Alloy Steel | Very High | Moderate | Very High | Heavy | Moderate | Aerospace gears, heavy-duty gearboxes, high-performance automotive gears, power generation turbines, and heavy-load lifting equipment (e.g., cranes). |
| Stainless Steel | High | Very High | High | Heavy | High | Gears for marine equipment, food processing machinery, medical devices, pharmaceutical processing, and chemical plant machinery. |
| Cast Iron | Moderate | Low | Moderate | Heavy | Low | Gears in compressors, pumps, printing presses, low-speed industrial machinery, and agricultural tools requiring good vibration damping and cost efficiency. |
| Brass | Moderate | Very High | Moderate | Heavy | High | Worm gears, bushings, gears in marine environments, chemical processing equipment, elevator mechanisms, and electrical switches where low friction and quiet operation are essential. |
| Aluminium | Low to Moderate | High | Low | Light | Moderate | Gears in lightweight aerospace components, robotics, electric vehicles, appliances, consumer electronics, and portable tools where weight reduction is critical. |
| Plastics | Low | Very High | Low to Moderate | Light | Low to Moderate | Gears in toys, printers, medical devices, food-grade machinery, lightweight consumer products, vending machines, and low-load office equipment like photocopiers and scanners. |
FAQ
The right material depends on the gear’s operating conditions:
- For high loads and durability: Steel or alloy steel is ideal.
- For corrosion resistance: Stainless steel or bronze is preferred.
- For lightweight designs: Aluminum or plastics work well.
- For cost-effective, low-speed applications: Cast iron is a good choice.
Consider factors such as strength, wear resistance, cost, and environmental conditions when selecting materials.
Heat treatment enhances a gear’s hardness, wear resistance, and fatigue strength. Processes like carburizing, nitriding, and induction hardening are commonly used to strengthen the gear teeth while maintaining a tough core for shock absorption.
Common challenges include:
- Achieving High Precision: Maintaining tight tolerances for applications like aerospace and robotics.
- Minimizing Wear and Tear: Selecting materials and finishes that resist wear under high loads.
- Reducing Noise and Vibration: Designing and finishing gears for smooth, quiet operation.
- Cost Efficiency: Balancing quality and production costs, especially for custom gears.
Custom gears are tailored to specific design requirements, including:
• Unique dimensions, tooth profiles, or materials.
• Special surface treatments or coatings for extreme environments.
• Enhanced performance for specialized applications (e.g., robotics, high-speed machinery).
Standard gears are mass-produced and follow industry-standard dimensions and materials, making them suitable for general-purpose use.
Production time varies based on:
- Complexity: Custom designs and tight tolerances take longer to produce.
- Quantity: Prototyping single gears is faster than mass production.
- Processes: Advanced finishing methods (e.g., grinding, lapping) increase production time.
On average, it can take days to weeks to manufacture custom gears, while standard gears are available immediately from stock.
How can we help you ?
Gears are indispensable to industrial projects and their success depends on the careful selection of contractors
Novelty Structures stands out as a reliable partner in providing High-Quality Gear Fabrication services tailored to demanding industrial needs.
