The roving spindle is approximately 1 meter long and is supported by an oil cup, spindle feet, and a spindle sleeve. It is made of high-quality high-carbon steel, heat-treated, and possesses high manufacturing precision and sufficient rigidity and hardness. The main body of the spinning spindle consists of the spindle rod and spindle disc, which combine to form a rotating body. The spindle rod is made of ball bearing steel, first machined or hot-rolled into a slender rod blank, then heat-treated and ground into shape. The bearing stop in the middle and the spindle tip at the lower end of the spindle rod must have high manufacturing precision, surface finish, hardness, and a wear-resistant metallographic structure.
The upper part of the spindle rod supports the bobbin and must be very straight, tough, and flexible. The spindle disc, bell-shaped and tightly fitted in the middle of the spindle rod, is made of cast iron or free-cutting steel and is the driving component of the spindle, driven by a spindle belt or auger belt. The upper bearing is housed within it, preventing fly shavings and dust from entering the bearing. The spindle feet support the entire spindle assembly and serve as oil reservoirs. The spindle hook is used to stop the spindle disc, preventing the spindle rod and spindle disc from being pulled away from the spindle foot or from violently moving during the removal of the bobbin. The brake is used to brake the spindle and yarn bobbin for splicing operations, and is required in cotton spinning of large packages, wool and chemical fiber spinning, and twisting.