Abstract: A block of machinable wax (B) is anchored to a fastening plate (A) with a layer of adhesive (20) in one embodiment and with wax machine screws (30, 32, 34) in another embodiment. The fastening plate and machinable wax block are adapted to be used in machine tools, such as numerical controlled apparatus for producing patterns and prototypes. The block of wax has a composition which includes 5 to 15 percent by volume paraffin wax with a melting point of 150.degree. F. to 152.degree. F.; 5 to 15 percent by volume microcrystalline wax having a melting point of substantially 190.degree. F. to 192.degree. F.; 5 to 10 percent by volume ethylene/vinyl acetate copolymer having a melting point of substantially 210.degree. F.; 25-35 percent by volume nonemulsifiable polyethylene wax having a melting point of substantially 240.degree. F.; 40 to 50 percent by volume nonemulsifiable polyethylene wax having a melting point of substantially 220.degree. F.