returnable wooden crates for vegetables
1983 Edition

The standard mandates that timber must be selected from Group II and Group III species as listed in Appendix A of IS 6662-1980. Only one species should be used per crate, or if multiple species are included, they must all belong to the same group (either II or III). The timber must be properly seasoned with moisture content not exceeding 18%, have grain inclination within 1 in 10, and be free from pith, insect damage (except isolated dead pinholes but excluding powder post beetles), rot, warping, splits, and objectionable knots. These measures ensure the crates possess adequate strength and durability for vegetable transport.

The specified crate overall dimensions are 500 mm in length, 300 mm in width, and 350 mm in depth, as per Clause 3.1. Component sizes include 6 end boards measuring 300 × 75 × 6 mm, 6 side boards at 500 × 75 × 6 mm, 4 bottom boards sized 500 × 75 × 10 mm, and 2 interior corner posts divided into 4 parts each with cross-section 350 × 50 × 50 mm, according to Clause 3.2 and Table 1. All dimensions are actual measurements after allowances for sawing, with moisture content controlled at 18%. Tolerances for internal dimensions, thickness, board widths, and lengths are specified in Clause 3.3. This standardization guarantees uniformity and interchangeability.

The dragging test, outlined in Clause 6.1 and Appendix A, involves filling the crate to its nominal capacity with vegetables or an equivalent load. The crate is prepared with all wiring and stapling as in normal transit conditions and placed on a flat concrete surface or smooth rod. It is then dragged horizontally for 6 meters, rotated 90 degrees on its axis, and dragged back to the starting position. This cycle is repeated 10 times consecutively. Immediately after completion, the crate is inspected for any visible damage that might compromise the contents. The acceptance criteria allow no more than one failing crate per lot, ensuring the crate’s robustness during transport.

Nailing and fastening specifications according to Clause 5.1 and Table 2 require clout-headed nails (IS: 723-1972) with lengths and gauges prescribed per joint type: one 12 mm nail (2.0 mm gauge) for side boards to posts and side to end boards; two 16 mm nails (2.0 mm gauge) for bottom to end boards; two 24 mm nails (2.0 mm gauge) for end boards to posts; and six 12 mm nails (2.0 mm gauge) for side boards to bottom boards. Additionally, the crate ends are secured with 3 mm galvanized, rust-resistant crescent wire, turned in approximately 50 mm from the box edge and fastened with four staples each at the side, bottom, and top. These fastening methods assure structural integrity and durability.

Yes, plywood is acceptable for crate sides and ends under this code. Clause 4.1.4 specifies plywood thickness of 4.0 ± 0.2 mm of CWR grade conforming to IS 303-1975. This plywood can be used alongside timber species from Groups II and III as per Appendix A of IS 6662-1980. The plywood must meet the dimensional requirements for boards (e.g., 300 × 75 × 6 mm for ends and 500 × 75 × 6 mm for sides). Utilizing quality plywood compliant with these specifications ensures the crates meet the standard’s durability and performance criteria.