Mill Girth Gears, Ring Gears, Bull Gears, Pinions and ShaftsMill Girth Gears comprise high integrity girth gears that find application in driving horizontal grinding mills. With these gears developed for achieving superior finish strength and process reliability, these can be designed for different kW applications as well as in diameter and weight choices. For ensuring in them flawless.girth gear for ball mill,Girth Gears - Ring Gears | Gearbox applications | David Brown .Girth / Ring Gears. If you need large diameter girth gears in your process machinery, then you need a product you can rely on. With a variety of options for cast, fabricated steel or SG iron and multi-segmented gears, David Brown Santasalo is your one stop shop for girth gears for AG, SAG, ball mill, kiln and dryer applications.