When a lid does not close fully, the gasket or latch usually takes the blame; the third possibility is play in the hinge. Wear between pin and bearing grows a little with every opening and closing, faster with sand and salt, slower with lubrication.
Play grows at the tip of the lid. Worked example: 0.2 mm of play in a 20 mm bearing tilts the lid by about 0.01 radian; at the free end of a 600 mm lid that is 6 mm of movement. Wear of under a millimetre in the bearing turns into a visible misfit at the lid.
Measure like this:
- With the container empty, bring the lid to a half-open position and use the same position every time.
- Hold it at the free end and move it up and down without forcing it.
- Read the movement at the tip with a ruler or dial indicator, always against the same reference surface.
- Measure both corners of the lid separately; do not average them.
- Write the container ID, the date and a photo of the measuring point on the maintenance card.
| Finding | Reading |
|---|---|
| Small play at both corners | Normal wear |
| One corner clearly larger | Adjustment or replacement of the hinge on that side |
| Large play at both corners | Pin and bearing set worn |
| No play, yet the lid closes stiffly | Alignment, latch or dirt |
There is no general limit for hinge play; the criterion is that the lid seats squarely on the gasket. That is why the first reading, taken when the container is new, becomes the reference. Three readings over three years show the wear rate and the time to replace. Do not compare figures between different hinge models; for the dismantling and adjustment steps, ask Aris Makina for the model instruction.
