A wire strapping or tying device (46) is provided having a rotatable pinion-type knotter assembly (56) for twist-knotting of a pair of adjacent wire sections (50a, 50b), together with a shiftable knotter cover (266) movable between a home position for maintaining the sections (50a, 50b) within the assembly (56) and a remote knotter access position allowing ready access to the knotter assembly (56). The cover (266) is supported by arms (268, 270) which are pivotal about an axis spaced from and generally parallel with the cover (266). The cover (266) may be manually shifted to the remote knotter access position through an arc of at least 45°. Also, the knotter assembly (56) includes a primary body (128) supporting a rotatable, slotted knotter pinion (178). The body (128) is pivotally secured to frame plates (68, 70), allowing the body (128) to be pivoted to a convenient position for servicing of pinion (178). Preferably, a mechanical operator assembly (198) is employed to sequentially operate all of the device components in a precise, timed sequence. A single drive assembly (196) preferably in the form of a piston and cylinder assembly (200) is used to actuate the assembly (198).