Abstract: Apparatus for forming a multiplicity of thin wafers from at least two similar blocks, the apparatus comprising a supply reel (1) to supply wire, an upper pair of parallel spaced roller guides (3a,3b) having a multiplicity of circumferential grooves on their surfaces, a lower pair of parallel spaced roller guides (3c,3d) having a similar multiplicity of circumferential grooves on their surfaces and spaced apart from the upper pair of roller guides in a plane generally parallel to and spaced apart from a plane defined by the axes of the upper pair of roller guides, and a collection reel (2); the arrangement being such that a wire from the supply reel can pass around successive grooves along the roller guides from near the supply reel to near the collection reel, so to form a four sided continuous web of wires along the length of the roller guides and means to drive the wire rapidly from the supply reel to the collection reel, and means to move the blocks (4) through the web of wire between the pairs of roller g