This application relates to the field of beading tools, and in particular to, a beading apparatus. The beading apparatus includes a bottom seat, a drive member, a rotation shell, and a needle-like assembly. The bottom seat has a placement surface for contact with an operation surface. The drive member is connected to the bottom seat. The rotation shell includes an accommodating body and a baffle, the accommodating body is connected to the drive member, the drive member drives the accommodating body to rotate, a rotation axis of the accommodating body is inclined with respect to the placement surface, the accommodating body is provided with an accommodating chamber for accommodating a bead-shaped structure, the accommodating chamber has an opening, and the baffle is connected in the accommodating chamber. The needle-like assembly is located on a side of the rotation shell, and at least part of the needle-like assembly extends into the accommodating chamber via the opening. The beading process is simple and quick, and the rotation axis of the rotation shell being inclined with respect to the placement surface can reduce the case of scattering the bead-shaped structure from the rotation shell. The baffle allows the bead-shaped structure to fly a greater distance, which is conducive to increasing the beading success rate, thus improving the beading effect.

Disclosed is a dummy shaft which prevents washers from falling off. In addition, disclosed are an apparatus for assembling a differential unit using the dummy shaft, and a method for manufacturing the differential unit. Specifically disclosed is a dummy shaft for temporarily assembling a differential unit by being inserted into a pinion gear, and a washer in contact with an outer surface of the pinion gear, including a body portion, and a movable portion slidable in a direction toward or away from the body portion. The movable portion has a receiving groove for catching the washer.