Abstract: A process and an apparatus (10) for the production of a plastic article of large area and small wall thickness, wherein the plastic material (90) is injected in the viscous condition into a mold cavity which is defined by a bottom mold portion (20) and a top mold portion (36). During the operation of injection of the viscous plastic material, which takes place through an inlet (76), the top mold portion (36), with the bottom mold portion (20), forms a pre-molding cavity (86) which is enlarged in a wedge shape starting from the inlet (76). During injection of the viscous plastic material (90) into the pre-molding cavity (86) or immediately after the injection operation, the bottom and top mold portions (20, 36) are moved relatively towards each other, forming the definitive mold cavity (78), so that the viscous plastic material is uniformly distributed in the diminishing mold cavity.

Abstract: A lead sharpener comprises a housing formed by relatively rotatable lower and upper housing portions containing a milling cutter of which the operating face extends at an acute angle to the longitudinal axis of a guide passage through which the lead that is to be sharpened is introduced. To enable the sharpened point of the lead to have a selected configuration, the guide passage is provided in an insert member which is rotatable in a hole provided in the upper housing portion, the arrangement being such that the longitudinal axis of the guide passage does not coincide with the rotary axis of the insert member whereby, upon rotation of the insert member, the spacing and possibly also the angle between the longitudinal axis of the guide passage and the operating face of the milling cutter are changed.