Introduction to Gears

Gears are one of the most fundamental mechanical devices in the world. Gears are particularly useful for the transferral and translation of rotary motion, and are able to manipulate speed, torque, and rotational axis within a given machine. Gears are so integral to our everyday lives that they can be found almost everywhere, from cars to clocks.

Spur Gears, Bevel Gears, and Mitre Gears

Accu’s Gear range comprises three main variants: Spur Gears, Bevel Gears, and Mitre Gears - and all three are very much different gears for different applications.

Spur Gears are intended for the transmission of rotary motion between parallel shafts, and can be used in different gear ratios to alter the speed and torque of a mechanism.

Mitre Gears are sold in pairs of 1:1 ratio angled gears, making them primarily suitable for translating rotary motion through an angled drivetrain without altering speed or torque.

Bevel Gears are sold in pairs, similarly to Mitre Gears, but are sold in different gear ratios, making them most suitable for converting gear speeds along an angled drivetrain.

Straight Tooth Gears vs Spiral Gears

Accu offers Bevel Gears and Mitre Gears in both Straight Toothed and Spiral Toothed (sometimes called ‘Helical’) configurations. Spiral Gears generally run much quieter and more smoothly than Straight Toothed Gears due to the gradual engagement of each individual tooth – this has the added benefit of reducing wear on each gear. Spiral Gears are also generally stronger, with each elongated tooth creating a larger surface contact area during operation. However, Spiral Gears are generally more expensive than their Straight Toothed equivalents, and also have a negligible negative impact upon mechanism efficiency, which means they are rarely used in high-performance applications such as autosport.

Curated Video - More Than You Need To Know About Gears!

If you'd like to know more about gears, this video from This Old Tony does a fabulous job of introducing the watcher to all aspects of gears from the basics to cutting your own. The timestamps below can be used to jump to specific sections of interest if you don't have the time to watch this epic in full!

• Gear Basics: 0:00-10:50
• Gear Cutters: 10:50
• Indexing & Dividing: 14:18
• Dividing Head: 19:43
• Cutting a gear: 24:42
• Example application: Metal gears in the mini-lathe: 26:28