Cover depth is the number most eyewear briefs leave out, and it is the one that decides how the closed box looks. A cover that stops halfway leaves a band of tray on show. A cover that runs to the table hides the join completely. Both are correct boxes; they are simply answering different questions.
What Lid Depth Actually Measures
Depth belongs to the cover on its own: from the top panel, down the inside of the wall, to the lower edge. It is a single measurement taken on one shell, and it has nothing to do with how tall the finished pack stands.
Depth Is Not Wall Height
A wall can be tall and still leave the base showing, because the base itself has height. The figure that matters is the cover wall minus the part of the base it has to clear, and that subtraction is where most drawings go wrong.
Put the other way round: if you want no band of tray to show, the cover wall has to be at least as long as the base is tall, plus the thickness of the board in the base floor.
Why the Closed Box Looks Like One Solid Block
When the cover wall runs the full height, its lower edge lands where the box meets the table. At that point the join is seen edge-on, and an edge-on join is invisible from any normal viewing angle.
That is why a deep cover reads as a solid block rather than as two parts pushed together. It also explains a common support question: buyers who receive the box sometimes report a missing seam, expecting one to be there.
The Join Appears Only When the Cover Lifts
Lift the cover a centimetre and the join is unmistakable: two wrapped edges, one inside the other, with the blue band of the base mouth between them.
This is worth knowing before a photo shoot. Shot closed, the box has no visible split; shot half-open, it has a strong one. Neither is a defect, and the choice of angle is the whole story.
Depth Is Not Overlap
Overlap is how much of the base the cover covers when the pack is shut. Depth is the length of the cover wall. On a box where the cover reaches the table the two numbers coincide, which is why the words get used interchangeably and why quotes go wrong when only one of them is given.
A Deep Cover Protects More Than a Shallow One
Every millimetre of cover above the contents is a millimetre of board standing between the frame and whatever the carton meets in transit. On a 5 cm deep eyewear box the frame sits low in the tray and the cover carries the load across its top panel instead of pressing on the bridge.
A deep cover also stiffens the pack. Two shells overlapping along their full height behave like a tube, so the walls resist twisting in a way that a shallow cover with a short overlap cannot match.
Where a Deep Cover Costs You
Two costs, and both are real. The first is material: a longer cover wall means more board and a larger wrap per shell. The second is feel, because a deep cover has a long sliding fit, and if the tolerance is loose the cover will rock before it lifts.
Neither cost is hidden. Both show up on the drawing as a decision about how much clearance to leave between the two shells, which is normally a fraction of a millimetre on each side.
Measuring Depth on a 15 x 8 x 5 cm Box
On this box the three outside figures and the cover depth line up, which makes it a useful worked example.
One box, five numbers
| Measurement | Value | Comment |
|---|---|---|
| Outside length | 15 cm | Long side of both shells |
| Outside width | 8 cm | Short side of both shells |
| Outside depth | 5 cm | Table to the top panel |
| Cover wall | About 5 cm | Runs the full height, so the edge meets the table |
| Base wall | Equal on all four sides | Drops into the cover |
When the Cover Should Stop Short
Not every brief wants a hidden join. A cover that stops one or two centimetres above the table creates a colour break, a place for a printed band, or a visual cue that the box opens upwards. Shallow covers are also easier to lift one-handed on a counter.
The question to settle is what the closed pack should look like, because the depth follows from that answer and not the other way round.
A Note on the Pouch
The velvet drawstring pouch sits inside the tray and changes nothing about cover depth. It does change the height of the contents, so if a pouch is added to a box that was drawn without one, the frame rides higher and the clearance under the cover shrinks.
What to Send Us for a Lid Depth Quote
Send the outside size, the depth you want the cover to run, the paper and the lining route. Those four are enough to price the box and to cut a die.
A sample request is the fastest way to judge depth in the hand, since photographs flatten exactly the detail being decided. The FAQ answers the rest, and the construction follows the same rules as every lid and base box we build.
Who Makes This Box
The workshop has run since 2004, covers 5,000 square metres, employs more than 50 people and ships to over 30 countries. Quality management follows ISO 9001:2015 under certificate ZYC24Q00141R1S, valid to 28 November 2027. More about the plant is on the workshop page.
