A high strength sieve which is lightweight and durable without having to add springs, and without requiring a high level of force to effect adjustment of the louvers. The high strength sieve utilizes hollow tubes to support the louvers. Providing hollow tubes (i.e., rather than solid wires) allows for larger diameter holes to be used in the frame. This provides for increased bearing surfaces, as well as provides for better tolerances. This reduces the movement of the tubes within the holes. Preferably, the tubes are mounted in the frame through holes which are extruded, thereby providing for increased bearing surfaces and a tighter fit. The extruded holes also provide a natural lead-in for the insertion of the tubes (i.e., during assembly of the sieve). Alternatively, solid wires can be provided extending through the extruded holes instead of hollow tubes.