A device for rotating with a rotatable first member includes a second member having a portion engageable with the first member. The portion has a first part and a second part which is resiliently biased away from the first part. The second member tightly engages the first member. There may be a device for measuring rotation of the shaft such as a potentiometer. The rotation measuring device may include an electrical connector for the potentiometer including a socket and a post which is pressable into the socket. The device may also include a rotationally adjustable connector. There may be a coupling connected to the second member which includes a third member with a portion having n sides and a fourth member with a portion having n sides which receives the portion of the third member in a mating relationship, thereby allowing the device to be adjusted to a total of at least m.n rotational positions. The second member preferably has a projection which slidably engages a slot in the third member allowing for non-coaxial rotation, and minimal backlash, of the device for measuring rotation relative to the first member.