Blind riveting apparatus and methods

A friction stir blind riveting apparatus comprising:

• a motor, wherein the motor is a driven motor;
• a clamp for gripping a mandrel of a blind rivet, the clamp being movable along the axis of the mandrel;
• a first transmission configured, when engaged, to transfer rotary motion of the motor to the clamp so as to cause rotary motion of the clamp;
• a second transmission configured, when engaged, to convert rotary motion of the motor to linear motion of the clamp, and thereby retract the clamp to pull on the mandrel, when engaged;
• a transmission control apparatus arranged to selectively adjust the degree of engagement of at least one of the first and second transmissions, the transmission control apparatus comprising a variable-influence brake or clutch;
• and
• wherein an amount of slip the brake or clutch permits while the motor is being driven can be varied from no slip at all permitted, to slip being completely unrestricted, and anywhere in between.