Worm Gear Oil

These lubricants have been used extensively in worm gears with great success in a wide variety of applications. Compounded gear oil is a mineral basestock with normal rust and oxidation inhibitors that is blended with four to six percent acidless tallow or synthetic fatty acid (the compounding agent). The surface-active compounding agent gives these products excellent lubricity and prevents sliding wear in worm gears.

EP mineral gear oils are used more extensively in worm gears. Under conditions of high pressure and temperature, the EP (antiscuff) additive reacts with the metal surface to form a soft, slippery chemical layer which prevents severe wear and welding. Previously, there was a concern that sulfur-phosphorous EP additives would react with the bronze gear. However, new EP additive technology used by most of the major lubricant suppliers has reduced the corrosive attack by utilizing nonactive sulfur. EP lubricants work particularly well when shock loading occurs. EP gear oils also protect steel gears better than compounded gear oils.

Two major types of synthetic gear oils have been used successfully in challenging conditions with worm gears: polyalphaolefins and polyalkelene glycols.
Polyalphaolefins (PAOs) are the most common type of synthetic lubricant. They have good high and low temperature properties and are compatible with most mineral oils. Unlike some synthetics, PAOs don't attack paints or seals. Most formulations contain a small amount of organic ester or antiwear mineral that improves boundary lubrication conditions. Products that contain EP additives are also available.