FEFCO 0205: Center special overlap slotted container (CSO)
This is a center special box whose outer flaps are lengthened to overlap part way. The inner flaps meet in the center and the outer flaps overlap over them, giving a full inner layer plus an overlap strip outside.
Dieline
Construction
- Inner flaps are L ÷ 2 and meet in the center, as on a CSSC.
- Outer flaps are longer than W ÷ 2 by the chosen overlap. Packgent draws a 1 in overlap.
- Like other center special styles, the slots are offset and some board is trimmed.
| Part | Size |
|---|---|
| Inner flaps | L ÷ 2 |
| Outer flaps | (W ÷ 2) + overlap ÷ 2 |
Closure. Staple or glue through the outer overlap, or tape over it.
Blank size
Nominal blank width is H + L when L ÷ 2 is longer than the outer flap; otherwise H + W + overlap.
| Board | Nominal blank, in | With allowances, in | Area, ft² |
|---|---|---|---|
| B flute | 53.25 × 26 | 53.75 × 26.25 | 9.8 |
| C flute | 53.25 × 26 | 53.88 × 26.31 | 9.84 |
| BC double wall | 53.25 × 26 | 54.38 × 26.56 | 10.03 |
Allowances add one caliper per vertical score and per flap score. Your box maker sets the real scores. Work out other sizes with the box blank calculator.
Estimated compression strength
Simplified McKee estimate for the empty box at 18 × 8 × 8 in. The flap style barely changes McKee's answer, because it depends on the walls; extra flap layers help with drops and side stacking more than with top-to-bottom load.
Estimate only. Confirm with an ASTM D642 test before relying on it. Run the McKee calculator.
When to use it
Good for
- Long boxes that need a closed inner layer and a stapled or glued outer closure
Watch for
- Specify the overlap
- Board use is close to a CSSC, set by the inner flaps
Open the Spec Builder to check style, grade and dimensional weight for your product.
Sources
- Fibre Box Association, "Box Styles Basics" (2014), hosted by IoPP
- FEFCO: The FEFCO Code (International Fibreboard Case Code), 12th edition
- McKee, R.C., Gander, J.W. & Wachuta, J.R. (1963). "Compression strength formula for corrugated boxes." Paperboard Packaging 48(8): 149–159
Last reviewed . See all sources and how Packgent computes.