Frustrated about requiring one very specific part and not being able to find what you need? Yeah, we completely understand the feeling. Nothing’s more irritating than being held up because one piece of the puzzle is missing.

You don’t need to worry any longer. REMPCO is here to lend you a hand. We know we have the part you’re looking for, and if by chance we don’t, we provide the expertise to craft it. But information can be just as important. You might not always know exactly the part you require, so let’s shed some light in this post on spur gears.

Before you purchase the parts, here’s some essential information you should know about spur gears so you can be sure that spur gears are indeed the right solution for you!

How Spur Gears Work

Best to start with the basics. Spur gears are the most common type of gear. They’re also arguably the simplest and are widely used. So how exactly do spur gears work? To start, here’s what makes a spur gear, well, a spur gear!

  • Spur gears are cylindrical
  • They have straight teeth and are mounted on parallel shafts
  • Spur gears have an involute profile and mesh one tooth at a time
  • Involute form means spur gears only produce radial forces (no axial forces)
  • This involute method of meshing causes high levels of stress on the gear teeth, and therefore, high noise production, especially when used at higher rates of speed, such as automobiles

Two Types of Spur Gears


  • Teeth are cut on the outside surface of the cylinder
  • Two external gears mesh together and rotate in opposite directions


  • Teeth are cut on the inside surface of the cylinder
  • External gear rests inside the internal gear and the two gears rotate in the same direction
  • More compact than external spur gears as the shafts are positioned closer together
  • Often used in planetary gear drives, which are more complex to construct given the multiple moving parts

What Materials Spur Gears Are Made From

Spur gears are so common and multiple in their uses that you can find them applied all over and constructed from an assortment of various materials, including plastics. However, strong metals that are easily fabricated and molded, but also durable and strong, are preferable in most cases.


  • Type of plastic polymer used in its pure state or slightly altered state and is much stronger than common plastic
  • Can be molded into any shape
  • Produces less noise
  • Once hardened in the shape of  a spur gear, it becomes stiff and resistant to abrasion
  • Malleability, strength and resilience make it an option for spur gears

Cast Iron

  • Easily moldable material
  • Highly resistant to rust
  • Inexpensive as it is comprised of several metal ingredients
  • Can be incredibly strong or weak depending on the admixture
  • Produces loud noise, especially at high speeds

Stainless Steel

  • Most popular material for spur gears and others
  • Is a metal alloy comprised of two or more distinct elements melted together
  • Highly resistant to oxidation and abrasions
  • Strong and durable as well as corrosion resistant
  • Produces loud noise, especially at high speeds

Where Spur Gears Are Used

Given the basic function and commonality of spur gears, the simplicity of them makes spur gears common in all sorts of machines. They provide increased torque and don’t experience high losses from slippage because of their design, so usually spur gears have high transmission efficiency.

Due to the loud noise they produce at speed, spur gears are not used in automobiles, but can be found across a wide array of applications, such as the following:

  • Gear Pumps & Motors
  • Construction Equipment
  • Large Home Appliances
  • Handheld Kitchen Appliances
  • Energy Conversion
  • Fuel Pumps
  • Aircraft Engines
  • Power Units
  • Marine Engines

More Information

The great thing about machined parts, and gears in particular, is that every component and function can be different for the specific task needed. REMPCO understands that, which is why we scour the planet to find either the part you need in our database or reverse-engineer them to the latest industry standards and exact specifications.

There is plenty more to learn about spur gears and beyond, so now that you know a little bit more, contact us today for additional information and purchase the parts you need!