The pepper grinder was now empty. An ideal time to see how it worked and how it was put together.
You grind pepper corns by turning the white disc on top so the holes are open. Turn it upside down and twist the black cap and the ground pepper comes out of the holes.
But how is the thing constructed?
But the moving part that you twist - the black cap - is captive. It twists but doesn’t unscrew or come off. The rest of the grinder is a glass container. So I could break the glass or destroy the black cap. I chose the latter. You can see the ridge which holds the cap in place on the glass bottle (red arrow).
The white plastic disc was easy to prise off:
The inside of the black cap looks like this - see right. The helical grinding protrusions turn as you twist the cap and act against a white hard plastic insert in the top of the glass bottle. Lugs sit in depressions in the glass to stop the white part turning. The pepper corns fall between the black component and the stationary white disc and are ground on their way out.
And that’s how a throwaway pepper grinder’s constructed!
(Interesting that the grinding parts are made of plastic which you might think is too soft for the job. Basically it is and wears down over time. But it’s hard enough to grind the contents of the bottle before it wears down too much.)