A receiving surface (625) for use in the supersonic welding of the welding boss (620) of an M cassette tape reel (612a) is composed of the lower surface of a ring portion (626) which is formed so as to extend annularly along the base end of a hub central portion (621) formed in the bottom surface (616a) of a lower reel (616) and also which is projected downward (in FIG. 2) by a given amount from the bottom surface (616a). That is, the receiving surface (625) is situated slightly outside in the radial direction from directly below the welding boss (620).

A strip-like recording medium, in particular a magnetic tape, is provided with at least one self-threading leader which wraps smoothly onto the periphery of a cylindrical body, the recording medium and the leader being joined to one another, over their butt joint, by a piece of splicing tape. The leader and the piece of splicing tape have a predetermined length which approximately corresponds to the circumference of the cylindrical body. A reel comprises a hub and a roll of recording medium with a leader at the beginning and/or end of the medium, the leader being attached to the medium by a piece of splicing tape of said predetermined length.

A method of attaching a tape having longitudinal edges to a tape cartridge reel includes cutting an end of the tape non-perpendicularly to the longitudinal edges laterally across the width of the tape. The end of the tape is then attached to the tape cartridge reel. The method may also include cutting an end of the tape such that at least two of the laterally spaced apart servo stripes running longitudinally along the tape are cut at different longitudinal positions along the tape. The method may further include cutting the tape end such that at least two of the laterally spaced apart data tracks running longitudinally along the tape are cut at different longitudinal positions along the tape.