Abstract: An electrical connector for transformer studs accommodates two different size transformer studs, at different times, in a slip-fit blind bore. A large circular bore is threaded and over-sized for a slip fit of a stud of the largest size with ample clearance space to facilitate placement of the large stud in the bore. A smaller threaded recess is created by an arc formed in a periphery of the large circular bore and is sized to fit a smallest stud. A set screw holds the smaller stud in the threaded recess or the larger stud in the large circular bore. The matching threads provide an effective, efficient, long-lasting, and sturdy electrical transformer connection.