Overview of Spur Gears – Everything You need to Know

In their most simple form, a spur gear is a circular steel disc with teeth around the perimeter.  Spur gears are probably the most common gears. These teeth work in conjunction with other gears to create a rotation.  The “toothed” edges cause these gears to look like a spur on the back of a cowboy’s boots. The gears are mounted on shafts that stand parallel to another, and this allows the spur of the first gear to interlock with the spurs of the second and create a rotation.

Spur gears are used in many industries, from the tiny spur gears in an analog watch, to the complex assortment in a car or aircraft engine, and up to the mechanics behind the world famous Big Ben in London.  Spur gears are all around us.

Definitions and Terms Associated with Spur Gears

Ratio: the ratio is determined by the number of teeth in a pair of gears.  For example, a 2:1 ratio exists if a device contains two gears, and one gear has two times the teeth of the other.  

Gear Trains: gear trains are made of multiple gears. Gears run together in multiple sets to reduce or increase the speed of the drive.

Gear reduction: this is an arrangement of gears in which the speed can be lowered for a slower output.

What Does A Spur Gear Do? 


As mentioned earlier, spur gears are used in a myriad of industries, and at IPG we manufacture a wide range of spur gear types and sizes for various industries including agriculture, automotive, automation, robotic, food processing, and 3D printer equipment, just to name a few.

Anywhere you see a motor or some type of rotation, there are likely spur gears involved. Common applications for spur gears are to increase or decrease the speed of the rotation, to reverse the direction of the rotation, to maintain a synchronized rotation between two axes, and to move rotational movement from one axis to another.

Understanding the concept of the gear ratio mentioned before is important.  If one gear is spinning at a rate that is twice as fast as the second gear, this is a result of the ratio between the gears.  In the example given above, if the diameter (the measurement from one side of the gear straight across to the other) is twice the size of the diameter of the second gear, then this is a 2:1 gear ratio.  The industry calls this a “two to one.”  In application, what this means is that each time the larger gear makes a full rotation around once, the smaller gear makes a full rotation around twice. [1]

How Spur Gears Help Alter Operating Speeds

If both gears had the same diameter, they would rotate at the same speed but in opposite directions. However, to increase or decrease speed, gears are often connected together in gear trains.

In a gear train, multiple gears of various ratios are joined together. Each gear turns at a higher rate than the gear before it.  This enables rotations in your designated time to increase at incredible speeds in a relatively simple process. 

For example, in the diagram below, four gears are in a gear train. In this gear train, the smaller gears are one-fifth the size of the larger gears. So, if you connect the second gear to a motor (1st gear) spinning at 100 revolutions per minute (rpm), the third gear will turn at a rate of 500 rpm and the last and smallest gear will turn at a rate of 2,500 rpm. Similarly, you could attach a 2,500-rpm motor to the smallest and last gear to get 100 rpm on the second gear. [2]

Advantages of Spur Gears

Spur gears have many advantages across applications.  The teeth provide the power behind mechanical processes we depend upon.  The teeth, often made of steel or other durable metals, prevent slippage between the multiple gears. This creates synchronization of the axles and the gears which are connected to each other.

Another advantage of the spur gear is they make it possible to know precise gear ratios. This occurs by counting the number of teeth in the two gears and then dividing the number.  For example, if one gear has 80 teeth and another has 20 teeth, the gear ratio between these two gears when they are connected to each other is 4:1.

Another very helpful advantage of spur gears is that they make it so minute imperfections in the measurements (diameter and circumference) of two gears do not cause major trouble. The gear ratio is still controlled by the number of teeth even if the measurements of the two gears are a slight amount off.

Disadvantages of Spur Gears

There are some disadvantages to spur gears.  The teeth endure stress, they cannot transfer power or energy over long distances, they are typically very noisy, and they require parallel axes to function. [3]

IPG’s Superior Customization Capabilities

Our goal at Illinois Pulley & Gear is to provide you with professional, high-quality, reliable services.  We manufacture a large variety of high-quality, made on demand, timing pulley stock and all the necessary spur gears. We are virtually unlimited in the variety of services we can provide from gears to your full-functioning pulley system.  IPG can produce stock or made-to-order timing pulleys with any of the tooth profiles listed here. Note: HTD, GT, and GT2 are registered trademarks of the Gates Mectrol Corporation.

We want to be your go-to resource for all of your customization needs, and we want you to have the peace of mind that your projects are in good hands.  Click here to contact us with more information about our complete offerings or to receive a quote for your next project.

[1] https://science.howstuffworks.com/transport/engines-equipment/gear-ratio.htm

[2] https://science.howstuffworks.com/transport/engines-equipment/gear-ratio.htm

[3] https://clr.es

Gear & Pulley Manufacturing Glossary of Terms


Aluminum is the most common metal found on the Earth’s crust. It is notably light and thin, having about ⅓ the density of its metal counterpart, steel. Aluminum is used frequently in manufacturing settings.

Angular Misalignment

When two shafts in a piece of machinery become skewed, this is known as angular misalignment. This specific misalignment can result in unwanted torsion in machinery, causing unusual vibrations during utilization.

Bolt-On Flanges

Bolt-on flanges are known as the strongest and most durable flanges available for purchase. Flat head screws hold these flanges to the side of the pulley mechanisms. These flanges are removable if pulley maintenance is required at any given time.

Bore Size

Bore size is the diameter of the center hole in each pulley or gear. This center hole is used to mount the pulley or gear to a shaft often used with a keyway to assure no slippage between the shaft and pulley occurs.  


The circumference of a circle is, basically, the distance around the border of the circle. In the power transmission industry, the circle is a pretty common shape. To find the circumference of a given circle, simply multiply the diameter (distance across the circle) by pi (3.1415…). When it comes to pulley machinery, understanding the basics of the circle comes in handy, especially when looking at something such as gear ratios.

Drive Ratio

The ratio calculated between increased torque and decreased speed of machinery, or vice versa.

English-Metric Conversion

The two primary systems of measurement, English and Metric, are used all around the world. However, only a handful of countries — the United States and a few others — use the English system: the rest of the world functions on metric.

The English system uses inches, feet, miles, and pounds to measure quantities, while the metric system uses meters, liters, and grams to quantify these same measurements. In terms of weight, 1 kilogram is the equivalent of 2.2 pounds; likewise, 1 meter equals 3.28 feet. 


Located on the sides of the teeth, flanges could be described as the small “rings” found on the pulley. The pulley belt is held in place by these flanges, which sit on the outside of the belt path.

The importance of flanges is seen in the mitigation of angular misalignment — or the tendency of belts to relocate too far to one side or another.

Gear Ratios

Gear ratios have to do with gears working together in a system. A gear ratio of 2:1 communicates to the individual that one gear is twice as large as the other. And yes, the size of the gear does matter. It actually translates to the efficiency of the gear pair directly. Going back to circumference, a gear that has twice the circumference of another gear will only move half as fast as its half-sized counterpart.

Put simply, if the first gear has a circumference of 1 inch, and the next gear has a circumference of 2 inches, in order for the 1-inch gear to cover as much distance as the 2-inch gear, it has to move twice as fast.

The circumference of a gear also dictates the number of teeth on said gear. The bigger the gear, the more teeth on the gear. Counting the teeth on a gear is what dictates its gear ratio when compared to another gear.

Heat Shrinking

Large flanges, measured in diameter, are often attached to timing pulleys via heat shrinking. The process is simple: heat the flanges up to a specific temperature (450 degrees Fahrenheit), and set the hot flanges onto the pulleys’ flange step. When the flanges cool, they shrink into the perfect position upon the step.


Horsepower (HP), also referred to as “mechanical horsepower,” is found by calculating the work required in order to raise a weight of 33,000 pounds (lb) by 1 foot over the course of 1 minute. This term was created in the 1800s to equate the work of horses to the work of steam engines. 


A pulley is designed to aid the redirection of a rope or cable, often found in many different types of machinery.

Roll Staking

Roll staking serves as another way in which to attach flanges to timing pulleys of smaller proportions. Within this method, a crimp is formed around the edge of the flanges on 100% of the diameter, not just in a few key points. This yields a much better staking method for attaching flanges to a given pulley.

Set Screw

Also known as a “grub screw or blind screw,” a set screw is a piece of equipment used to secure two other pieces of machinery together, often without the use of a nut. It is often used to secure a pulley to a shaft.

Stainless Steel

Similar to steel in composition, stainless steel is commonly used in manufacturing and machinery. However, unlike steel, the composition of stainless steel prevents the metal from developing rust over time.


Steel is a metal composite made up of iron and carbon, as well as small amounts of silicon, phosphorus and other elements. This unique composition makes steel the most efficient and highly-used metal in engineering and construction.

Timing Belt

Also known as a “cambelt,” a timing belt operates in line with an engine’s intake and exhaust strokes. It ensures that each specific valve, whether for intake or exhaust, opens at the right time. This type of belt often works in tandem with the crankshaft and camshaft.

IPG offers an abundant variety of timing belt pulleys, with variations based on pitch, teeth count, bore size, keyways, setscrews, and more.


In the pulley industry, torque is the rotational equivalent of force. The more torque per rotation, the less speed necessary to produce the same amount of efficient work. The basic relationship is that an increase in torque yields a decrease in speed. This is known as the drive ratio.

Stainless Steel Pulley Stock

stainless steel pulley stock

At Illinois Pulley and Gear, we have a wide variety of materials to offer for your stock pulley project. Stainless steel is one popular material that has many benefits when it comes to durability in the field while also being aesthetically pleasing as well.

Below are just some reasons why stainless steel may be right for you: 

Benefits of Stainless Steel Pulley Stock

Stainless steel is a low-carbon steel that contains chromium at 10% or more by weight. The addition of chromium gives the steel its unique, stainless, corrosion-resistant properties it is well known for.

Durability & Strength

Strength-To-Weight Ratio:

While typically heavier than other metals, stainless steel is also significantly stronger and tougher. When compared against aluminum or plastic options, if it’s the strength you’re concerned with, stainless steel is likely the best option.

Heat & Corrosion Resistance:

Stainless steel is a popular option for process plants and many other applications because of its resistance to corrosion. The chromium alloy present in stainless steel makes the material resistant in atmospheric, pure water and most acid, alkaline solution or chlorine environments. This means stainless steel can be used anywhere without fear of rusting or other damage, which gives this material an incredibly long lifespan.

Special high chromium and nickel-alloyed grades of stainless steel pulley stock are also highly resistant to scaling and heat, retaining their strength even at high temperatures. Stainless steel is incredibly prevalent as a building material in heat exchangers, boilers, as well as aircraft and aerospace applications.

Long-Term Value:

Stainless Steel lasts longer than other metals like aluminum or brass because its properties make corrosion less likely; this means more time out on the job site without needing replacement parts from us.

When total life cycle costs are considered, stainless steel is often the least expensive material option. Due to its extreme durability, stainless steel components are built to last longer than any other option. The cost savings also come from the benefit of having a maintenance-free product.

Aesthetic & Hygiene

Aesthetic Value

Bright and easily maintained, stainless steel retains an attractive appearance for applications where aesthetics is important.

The beauty of using stainless metal brings elegance with each use which adds value to any company’s product line-up by providing customers with options they can’t find anywhere else. This will keep them coming back again and again over.


Stainless steel is extremely easy to clean and maintain. These qualities make it an ideal choice for food processing, hospitals, kitchens, and similar applications. Unlike aluminum, stainless steel also leaves no after taste on food products.

High Efficiency

Ease of Fabrication

Stainless steel can be cut, welded, bent, formed, machined, assembled, and fabricated as quickly and easily as traditional steel materials with modern steel fabrication techniques.

100% Recyclable

Over 50% of new stainless steel material is recycled and remelted stainless steel scrap, making it a material decision you can be both confident in and proud of!

Potential Drawbacks of Stainless Steel

While stainless steel is a great material that will work well for many applications, it’s not always the perfect solution.

  1. High initial costs associated with certain fabrication challenges of the material can make stainless an impractical choice for high volume or other applications.
  2. Stainless is also significantly heavier than aluminum, making it a less ideal fit for applications where lightweight is critical.

Stainless Steel Pulley Stock at IPG

Different needs arise across different industries and applications. Illinois Pulley & Gear will help you pick the best material for the job, depending on your required use. We provide high-quality, custom-made pulley stock for nearly every major industry, meaning we understand what your needs are and what will be the best solution.

If you’re looking for stainless steel pulley stock, browse our product catalog or get in touch with a member of our team today!

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Custom Poly-V Pulleys

custom poly-v pulleys

Poly-v pulleys are one of the most common pulley systems, utilized in a light duty to heavy duty machinery in a multitude of industries.

In fact, you are probably quite familiar with some common pulley applications, such as power tools, lathes, drills, and milling machines. Poly-v pulleys are desirable, because they’re extremely efficient.

However, poly-v pulleys are only effective if they are suitable for the task at hand. In other words, a pulley with the wrong pitch for your application will not work efficiently – if at all.

From profile to the number of ribs, the proper pulley must be chosen for your application. The following content provides insight into poly-v pulleys, including the most common components, helping readers understand how to customize poly-v pulleys for their needs best.

Poly-V Belt Pulley Components

Poly-v belts are unique because they have multiple longitudinal ribs. When considering a custom poly-v pulley, it is important to understand each component. Below, we discuss two common mechanisms: grooves and mounting styles.

1. Grooves

Grooves are intended to guide the belt while it is in motion, preventing the belt from slipping off the perimeter of the pulley. When used in transmissions, grooves also transmit motion. There are several different groove profiles to choose from: H, J, K, L, and M. Each profile is also available in a multiple of ribs.

2. Mounting

Mounting is the method of connecting the pulley to the shaft around which the pulley will rotate. Once again, the mounting method selected will depend on your application. For example, a simple bore with a bearing allows the pulley to rotate freely, often used in idlers or tensioning applications. Keyway mounting, on the other hand, transfers torque between the pulley and the shaft.

Additional Poly-V Belt Pulley Considerations

Along with poly-v pulley components, three additional measurements should be considered when selecting the right pulley for your application: belt profile, number of ribs, and pulley diameter.

  • Belt Profile: the belt profile is the size of the groove on the belt. Smaller grooves are well suited for light duty applications, while larger grooves are best for heavy loads.
  • Number of Ribs: increasing the number of ribs on the pulley increases the load that can be transmitted in the system.
  • Pulley Diameter: to find pulley diameter, simply use a ruler to measure from the outside edge to the outer edge of the pulley. Though the metric is simple to find, selecting the proper pulley diameter for your project can be a bit complicated. Mechanical advantage, HP transmitted, shaft distances, and a variety of additional factors come into play during pulley selection.

Advantages of Poly-V Pulleys

Poly-v pulleys have certain advantages innate to their design. The reduced thickness of poly-v belts make them very flexible, allowing them to wrap around very small diameters. Additionally, Poly-v belts can achieve higher peripheral speed than V-belts.

Poly-v belts also offer the following advantages:

  • Compact dimensions
  • High flexibility
  • High peripheral speed
  • High efficiency
  • Low noise
  • Possibility of using flat pulleys, reducing the cost of the system

Poly-V Pulleys vs Round Belt Pulleys

Poly-v pulleys are sometimes confused with round belt pulleys. Which do you need? Although these pulley systems are not the same, they have similar applications.

What are the primary differences between both systems?

The first difference between poly-v pulleys and round belt pulleys is the shape of the belt. Round belt pulleys have a belt which is round, similar to a rope of cord, that is gently sloped between pulley grooves.

The sides of a poly-v pulley, on the other hand, are sloped inward, forming a “V” shape (groove angle). The belt is also flat on one side.

The second difference is the surface of the belt. Poly-v belts have a larger contact surface area than round belt systems. Thus, poly-v belts are known for their efficiency and reduced energy consumption.

How Can I Customize My Poly-V Pulley?

Unique applications require unique poly-v pulleys. Unfortunately, pulley manufacturers do not always have the precise pulley you need on hand. This forces many individuals to purchase a pulley and then pay to have the pulley customized for their specific application. This process can be costly and time-consuming!

At Illinois Pulley & Gear, we offer complete customization right away. Our customers provide us with the precise specifications they need for their poly-v pulleys, and we provide the precise piece of equipment needed. In other words, we are a one-stop-shop, eliminating the need for another middle-man to provide customization.

What specifications can we customize?

Groove profile, number of ribs, bore size (English or Metric), keyway, set screws, lightning holes, are only a few examples of the specific requirements we customize for our clients. Additionally, our poly-v pulleys can be produced from a variety of materials, depending on your specific application. Some of our most common materials include aluminum, steel, stainless steel, and plastics. In other words, we can create the precise poly-v pulley needed for your project!

Illinois Pulley & Gear: Custom Poly-V Pulley Manufacturers

At Illinois Pulley & Gear, we manufacture a large variety of high-quality poly-v pulleys, made on-demand, according to your specific needs. Select your material, belt profile, and the number of ribs, and we will produce the product with precision. 

Beyond customization, our team is known for outstanding customer service. We are always happy to answer the phone, answer your questions, and provide helpful solutions. Do you have a question about a quote, pitch diameter, or the right material for your application? Get in touch. We would love to help.

You can reach our team at 847-407-9595 or via our online contact form.

What Are the Different Types of Gears?

what are the different types of gears

Gears are one of the most common, useful, and varied tools in machines. Simply speaking, gears are utilized to transfer motion between separate components. Depending on the unique characteristics of a gear, various kinds of motion and torque will be produced. Gears mesh together via carefully produced teeth. Most often, gears are mounted to a shaft.

Because gears are the building blocks of motion and torque, dozens of varieties have been created with unique advantages. For example, gears created for transmissions may not be optimized for another piece of machinery.  

What type of gear do you need for your project? If you are unsure, this blog is a great place to start! In the content below, we discuss three characteristics that differentiate gears, then dive into a list of gear types.

Gear Characteristics

Before diving into gear varieties, it is important to outline a few important characteristics that define each gear.

Gear Shapes

Gear shape seems rather self-explanatory at first consideration. Most gears are circular, right? While that is true, gears can be found in numerous shapes, including elliptical and triangular. Various shapes are designed for unique purposes. For example, circular gears produce consistent gear ratios – the output and input ratios are the same. If your project requires consistent torque, a circular gear is the best option.

On the other hand, uniquely shaped gears produce variable torque ratios. One industry resource writes: “Variable speed and torque enable non-circular gears to fulfill special or irregular motion requirements, such as alternatingly increasing and decreasing output speed, multi-speed, and reversing motion.”

Shape radically impacts gear functionality.

Gear Teeth

While in use, gear teeth interlock. Gear teeth are designed and constructed with unique characteristics.

For example, some gears are designed with teeth built into the gear body, while others are designed with inserted teeth that can be replaced as needed. Additionally, gear teeth may be added inside or outside the gear body. This is referred to as “internal” or “external” tooth placement. While one is not better than the other, internal vs external tooth placement will impact the motion of the gear. Finally, the tooth profile – or the shape of the teeth – will impact and influence the gear’s functioning characteristics, like speed and friction. Involute, trochoid, and cycloid are three of the most common tooth profiles.

Beyond design, gears can be acquired with various numbers of teeth and tooth angles. The customization capability of gear teeth is extensive.

Gear Configurations

There are three gear axes configurations: parallel, intersecting, and non-parallel/ non-intersecting.

Gears with parallel axes resided parallel to each other, one shaft rotating in the opposite direction of the other. Gears with intersecting axes intersect on the same plan. Non-parallel/ non-intersecting gears, such as screw gears, have axes that cross on differing planes. This configuration is not as efficient or fast as the other two.

Different Types of Gears

The following list will be explored utilizing the gear characteristic terminology discussed above.

Spur Gear

spur gear

Spur gears often operate on parallel shafts. Additionally, this gear runs with a single line of contact between teeth, meaning only one tooth is in contact with another at any given time. Single contact makes spur gears noisier than their similar counterparts, such as the helical gear. Regardless, spur gears are the most common type of gear because of their simplicity and precision.

Helical Gear

helical gear

Helical gears are designed similarly to spur gears and can be used to drive parallel axes or non-parallel/ non-intersecting shafts. Additionally, helical teeth are oriented at an angle, causing multiple teeth to be in contact with another at any given time. This produces a quieter, smoother operation.

Bevel Gear

bevel gear

Bevel gears operate on intersecting axes, specifically at 90 degrees. Like helical gears, bevel gear teeth are designed at an angle, causing multiple teeth to be in contact at once. All bevel gears are cone-shaped, but a variety of different bevel gears can be acquired, including: spiral bevel gears, straight bevel gears, and crown bevel gears.

Screw Gear

Screw gears resemble bevel gears. However, screw gears operate with a 45 degree twist angle on non-parallel/ non-intersecting shafts. Though important for specific circumstances, screw gears do not have an extensive load carrying capacity.

Worm Gear

worm gear

Worm gears are found in pairs, often comprised of a screw-shaped gear and a circular gear. Worm gears operate smoothly and quietly and produced large amounts of friction. Finally, they are used solely for non-parallel/ non-intersecting axis configurations and ideal for high-shock load applications.

Rack and Pinion Gear

rack and pinion gear

Rack and pinion gears are also found in pairs, comprised of a cylindrical gear and a gear rack. They are used for parallel axes configurations. Due to their design, rack and pinion gears produce high friction and stress.

Hypoid Gear

Visually, hypoid gears resemble bevel gears. Unlike bevel gears, they operate on non-intersecting shafts.

Illinois Pulley & Gear: Pulley Stock Manufacturers

At Illinois Pulley & Gear, we manufacture an extensive variety of high-quality timing pulley stock. Our stock is made on-demand, customized to the precise specifications of the customer. Pick your material, tooth profile, and the number of teeth, and we will produce the stock. 

If you are unsure of the precise gear you need, we would love to answer your questions and guide you in the right direction. Feel free to get in touch with our team of experts at 847-407-9595 or via our online contact form.