The most common complaint about a handmade box with a lid is the lid: it jams halfway down, or it is so loose it slides off when you pick the box up. Both are nearly always fixed by three settings in the box maker and a little care when folding. This works the same for the Box with lid, the Polygonal box, the Star lid box and the other boxes with a lift-off lid.
Why lids jam
Card has thickness. If the lid were drawn exactly the size of the base, its walls would sit where the base's walls are, and card cannot pass through card. So the lid has to be bigger than the base by the thickness of the card, and by a little more so it slides rather than squeezes. The templates here do this for you: the lid is enlarged by the material thickness plus the lid clearance you set. The site's own tests build every lid at each card thickness the tool offers, from 0.1 to 3 mm, and fail if one binds.
So when a lid does jam, the cause is almost always one of the things below.
1. The thickness setting is not your card
This is the big one. If the maker thinks your card is 0.3 mm and it is really 0.5 mm, the lid comes out too small for it. Measure the card you are actually using: callipers if you have them, or measure a stack of ten sheets and divide by ten. Set that as the material thickness. The card guide has typical thicknesses.
The same goes the other way: a thickness set too high makes the lid too big, and it falls off.
2. The clearance is too small or too big
The clearance is the extra room between the base and the lid. The Box with lid opens with 0.6 mm. Change it in small steps:
- Lid too tight, even with the right thickness set: raise the clearance a few tenths of a millimetre.
- Lid too loose: lower it a few tenths.
Small changes make a real difference, so change one setting at a time and test again rather than jumping by a whole millimetre.
3. The lid height
The lid height is how far the lid comes down the sides of the base. It does not change how tight the lid is, but it changes how it feels:
- A shallow lid, a third or less of the box's height, lifts off easily and shows the base, which suits a two-colour box.
- A half-height lid, the classic gift box, grips better.
- A full-height lid covers the base completely. It feels solid but takes longer to pull off, so give it a little more clearance.
The Box with lid opens with a 20 mm lid on a 40 mm deep box: half height.
4. How you fold matters too
A template can be exact and the box still come out wrong if the folds wander. A fold a millimetre outside its line on each wall makes the base a couple of millimetres bigger, which is more than the clearance.
- Score every dashed line before folding, so the card bends exactly on it. The scoring guide shows how.
- Fold the base and the lid the same way, both with the printed side in or both out, so the card's thickness lands on the same side of every fold.
- Glue the corner tabs inside, pressed flat. A tab glued outside the wall, or a bump of dried glue, adds thickness exactly where the lid has to slide.
- Let the glue dry before you try the lid. Damp card swells.
5. Test with the real card
A test box in printer paper shows the shape, but not the fit: printer paper is much thinner than card. For the lid, make one test in the card you will use, at the thickness you measured. If you are making a batch, test the first box before printing the rest. Making boxes in bulk has more on that.
Questions
My lid fits on one side but not the other. Why?
The box is not square: one corner was folded off its line, or a tab was glued crooked. Squeeze the base gently into shape before the glue sets, or check the folds on the side that binds.
Can I make the lid and base from different card?
Yes, and a different colour for the lid looks good. Use card of the same thickness for both, or set the thickness to the thicker of the two.
Which box has the neatest lid?
The Shoulder box: a neck stands inside the base and rises above it, and the lid slides over the neck and stops on the base, so the closed box shows one clean line round the middle. It is the perfume-box look, and it has its own clearance setting.
