Abstract: An improved utility knife has a blade housing, a handle region, and an end cap. The end cap is removably attached to the handle region. The handle region is cylindrical, with a slight taper and includes an interior storage chamber. The blade housing has a blade channel for holding a replaceable razorblade. A clench plate holds the razorblade securely within the blade channel of the blade housing.

Abstract: A multi-purpose work knife includes a universal elongate ergonomically-shaped handle (UEH) which defines an axis and includes a blade having an UEH blade axis. Within the handle portion, a channel member is received in a forwardly extending cavity and movably receives a cutting blade carrier for axial movement relative to the handle portion. A selectable non-universal portion (SNP) is secured at one end to said UEH at a plane of continuity of curvature thru which the UEH axis passes. The SNP holds non-standard blade at an angular offset relative to the UEH axis. A cutting edge of the SNP blades defines a virtual angle which intersects the UEH axis within a range of 20 to 30 degrees.

Abstract: A multi-purpose work knife includes a universal elongate handle (“UEH”) extending generally upon a UEH axis, the handle having a compound, convex curvature and an assembly within, at a top surface of a first end of the UEH, for holding a UEH utility knife blade in a selectable longitudinal position defined by a cutting edge of the UEH blade, said UEH also defining substantially oval radial cross-sections between the blade holding assembly and a second end thereof, the cross-sections defining slightly smaller radii at about a center region of said UEH, the second end including a complemental securement element; and a selectable non-universal portion (“SNP”) having a first end and a second end including an element for selectable for selectable complemental securement to said UEH complemental securement element, the second end of the SNP having a like radius and curvature to the second end of the UEH at opposing surfaces, the UEH axis passing through the complemental securement means of t