SM Spindles are used on medium to high torque applications which require rugged strength, such as metal rolling mill main drives and similar heavy equipment. Mill type spindles deliver maximum torque capacity under severe shock loads, while operating at relatively high angles. Gear sections are made from medium carbon and forged alloy steels with heat treated teeth. Hub gear teeth are Fully-Crowned to provide maximum torque capacity with minimum backlash. One-piece, molded lip-type seals, designed for operation under misalignment conditions, provide the most effective closure available to keep lubricant in and contaminants out. All spindles are designed so that the contact point of the thrust button is located on the centerline of the gear mesh. This provides ball and socket action, rather than the sliding motion that occurs if the contact point is located on the thrust plate.