What Are Spur Gears?
Spur gears are the most widely used straight-toothed gears designed for transferring motion and power between parallel shafts. Their simplicity makes them ideal for industrial applications requiring precision, durability, and high efficiency.
When you need reliable torque and smooth engagement in gearboxes, conveyors, packaging lines, or material handling systems, spur gears deliver performance without unnecessary complexity. Unlike helical or bevel gears, spur gears are cost-effective and easier to maintain — making them a staple in manufacturing facilities, processing plants, and automated machinery.
Key Spur Gear Specifications You Should Know
Selecting the right spur gear goes beyond tooth count alone. Understanding these core specifications helps ensure proper fit, performance, and service life.
Pressure Angle (14.5° or 20°) – The pressure angle affects how force is transmitted between meshing gears. Most modern spur gears use a 20° pressure angle for higher strength and load capacity, while 14.5° gears are typically found in older equipment, pressure angle cannot be easily identified without a gauge or specialized measuring tool.
Diametral Pitch (DP) – Diametral Pitch defines the size of the gear teeth and is calculated by dividing the number of teeth by the pitch diameter.
Examples:
- 48-tooth gear ÷ 4″ pitch diameter = 12 DP
- 28-tooth gear ÷ 1.75″ pitch diameter = 16 DP
The lower the DP number, the larger the tooth profile, meaning stronger teeth designed for higher loads.
Material Options – Spur gears are commonly manufactured from:
- Cast iron – economical and vibration-damping
- Steel – high strength and durability
- Brass – corrosion resistance and smooth operation
- Non-metallic materials – lightweight and quiet for specialty applications
Material selection directly impacts wear resistance, noise, and operating life.
Bore Size, Keyway & Set Screws – Many spur gears are supplied with a stock bore, while others can be modified with custom bore sizes, keyways, or set screws to match your shaft and torque requirements.
At MDS of Michigan, our selection of spur gears spans industrial sizes and configurations to match your exact application and horsepower requirements.
Need precision spur gears for your equipment? Browse our full spur gear inventory or call our experts at (800) 686-1627 for fast quotes.
