A surgical tool, comprising: an end effector, comprising: a first jaw member; a second jaw member, and a closure mechanism, wherein the closure mechanism is configured to move the first jaw member relative to the second jaw member between an open position for positioning tissue therebetween and a closed position for clamping tissue therebetween; a closure driver operably engaged to the closure mechanism; a firing mechanism advanced during a firing stroke, wherein said closure mechanism is operably engageable with and operably disengageable from the firing mechanism; a firing driver operably engaged to the firing mechanism; and a rotary drive shaft configured to drive the closure mechanism and the firing mechanism, characterised in that the rotary drive shaft is configured to simultaneously transmit rotation motions to the closure driver and the firing driver, thereby initiating advancement of the closure driver and advancement of the firing driver simultaneously such that the closure movement of the first jaw member from the open position to the closed position occurs simultaneously with an initial advancement of the firing mechanism until the closure mechanism is operably disengaged from the drive shaft thereby allowing the firing mechanism to be driven by the drive shaft independently of the closure mechanism for a remainder of the firing stroke. an end effector, comprising: a first jaw member; a second jaw member, and a closure mechanism, wherein the closure mechanism is configured to move the first jaw member relative to the second jaw member between an open position for positioning tissue therebetween and a closed position for clamping tissue therebetween; a closure driver operably engaged to the closure mechanism; a firing mechanism advanced during a firing stroke, wherein said closure mechanism is operably engageable with and operably disengageable from the firing mechanism; a firing driver operably engaged to the firing mechanism; and a first jaw member; a second jaw member, and a closure mechanism, wherein the closure mechanism is configured to move the first jaw member relative to the second jaw member between an open position for positioning tissue therebetween and a closed position for clamping tissue therebetween; a closure driver operably engaged to the closure mechanism; a firing mechanism advanced during a firing stroke, wherein said closure mechanism is operably engageable with and operably disengageable from the firing mechanism; a firing driver operably engaged to the firing mechanism; and a rotary drive shaft configured to drive the closure mechanism and the firing mechanism, characterised in that the rotary drive shaft is configured to simultaneously transmit rotation motions to the closure driver and the firing driver, thereby initiating advancement of the closure driver and advancement of the firing driver simultaneously such that the closure movement of the first jaw member from the open position to the closed position occurs simultaneously with an initial advancement of the firing mechanism until the closure mechanism is operably disengaged from the drive shaft thereby allowing the firing mechanism to be driven by the drive shaft independently of the closure mechanism for a remainder of the firing stroke.