Helical gears (sometimes called spiral gears) transmit power between parallel or right angle axes. For parallel shaft operation, helical gears with opposite-hand helix angles are required. For shafts at a right angle, you must use helical gears with same-hand helix angles.

As compared to spur gears, helical gears have smoother operation. Other advantages of helical gears over spur gears are their noiseless operation and longer life.

Some important parameters you must consider before buying helical gears are:

1. Forces and torques acting on the helical gears
2. Power transmission ratio (or gear ratio)
3. Dimensions of helical gears: pitch, module, pressure angle and diameters
4. Helix direction: right hand or left hand

Action Steps
The best contacts and resources to help you get it done

Buy helical gears from a reputable gear manufacturer

Once you have identified your power transmission requirements and have enough information about helical gears, you are ready to buy a helical gear.

I recommend: Boston Gear offers helical gears with both right and left-handed configurations. If you need double helical gears, check out helical gears manufactured by Carnes-Miller Gear. Atlanta Drive Systems is a reputable helical rack manufacturer that also supplies helical and straight gears. Sheffield Transmission Developments manufactures different types of gears, including helical bevel gears. Furthermore, you can buy different types of helical gears at other gear manufacturers such as Rush Gears and Nissei.

Buy helical gears from distributors or retailers

You can compare different helical gears based on their features and prices at distributors or retailers' websites.

I recommend: Quality Transmission Components, a reputable distributor of metric gears, supplies ground and hobbed helical gears. BDI, a distributor of a wide variety of transmission drive components, offers gears such as helical gears. You can purchase worm gear drives at Cone Drive. You can also refer to the list of helical gear suppliers at Gear Technology and ThomasNet.

Buy specialty or customized helical gears

If standard helical gears available in the market do not meet your requirements, opt for customized helical gears.

I recommend: Columbia Gear is a customized gear manufacturer that can design and manufacture helical gears as per customers’ requirements. If you have a helical gear design ready, you can contact Overton Gear for the manufacturing of your custom designed helical gear. Horsburgh & Scott can supply helical gears with diameters ranging from 3-360 inches. Dayton is another customized gear manufacturer that offers helical gears for metric and imperial dimensioning systems.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Ensure proper lubrication for your helical gears system.
• •  Use thrust bearings with helical gears to reduce thrust forces acting on the other components of your power transmission system.
• •  If you are designing a power transmission system, review the compatibility and effect of helical gears on other components, such as a bevel wheel or worm wheel.
• •  Gear details such as pitch, module and pressure angle are other important parameters you should consider for power transmission system design.