Abstract: A universal motor includes a commutator brush with a cavity for sheltering a constant force spring from a wire shunt. In some examples, the cavity can be formed by milling a blind hole into the brush such that an axial centerline of the hole is perpendicular to the brush's length. The cavity is near the back end of the brush, at the end farthest away from the commutator, but is also slightly forward to leave a rear portion of the brush to serve as a barrier between the wire shunt and the spring. The diameter of the cavity is slightly larger than the width of the brush, so the cavity creates a slot in the side of the brush. The slot allows part of the spring to reach out beyond the cavity to where the spring can hook onto a front edge of a stationary sleeve that supports the brush.