FTM 335 (FED-STD-791 Method 335) Gear Wear
Gears are rotating machine parts that have cogs designed to mesh with each other to transmit torque. To operate with minimal wear and a smooth rotation, gears must be properly lubricated – the chosen lubricant should have the appropriate load carrying capacity, wear resistance, oxidative stability and lubricity. Lubricant problems such as dirt contamination, acid formation, additive depletion and polymer shear may ultimately lead to machine failure. This method uses a gear wear testing apparatus to determine the relative lubricity of greases.
One weighed brass gear and one steel gear are mounted in a gear wear testing apparatus and coated with the test grease. A load is applied, and after a break in period, the apparatus is run for specified number of cycles. The brass gear is removed, cleaned, dried and reweighed. Reported is the average weight loss per 1000 cycles for a 6000-cycle run with 5-pound load and a 3000-cycle run with a 10-pound load. This is one of the only bench scale gear tests available.