of parts to be heat treated and organizing and feeding them into position for either first rollers 12 or second rollers 14 at the beginning or entrance of staging conveyor device 26 is a means for electronic product differentiation such as a load cell 28 fig4 which functions to weigh and determine the type of part to be heat treated arriving on a supply conveyor 30 depending upon the programming of load cell 28 and the weight of the incoming workpiece not shown load cell 28 will place the workpiece either on the top surface 32 of the staging conveyor device 26 as shown in phantom line in fig1 preparing the workpiece for entry into oven 10 on first roller 12 or alternatively may place the workpiece on bottom conveyor 34 of staging conveyor device 26 thereby preparing the workpiece for entry onto second rollers 14 other devices than a load cell 28 may equivalently be utilized to which product is placed on which conveyor or surface items entering staging conveyor 26 via supply conveyor 30 may include the workpiece itself or possibly a workpiece disposed in a rack or frame for ease of handling additionally wire type baskets may be used to contain the workpieces fig2 shows an opening 20 of oven 10 with a first transport means i e first rollers 12 oriented above second transport means i e second rollers 14 door assembly 24 previously referred to includes two rectangular doors i e top door 36.