A band clamp having a band and a nut and bolt fastener. The band includes radially-extending opposed flanges each having an aperture for receiving the bolt. The bolt has a shank that includes a neck, a threaded body for receiving the nut, and a tapered transition from the neck to the threaded body. In one embodiment, the tapered transition extends only partially around the shank such that a portion of the neck has a common surface with the body. During tightening, the radially inward facing surface of the aperture in the flange can engage the threaded body and slide along the threaded body across the common surface and onto the neck without having to traverse and ride up over the tapered transition. In another embodiment, the nut has an angled shoulder that engages the tapered transition when the nut is tightened to the desired axial position on the bolt.