Eli5, why do Mason jar lids typically come in 2 parts, threads and seal, as opposed to nearly every other commonly used household container?

Question

Eli5, why do Mason jar lids typically come in 2 parts, threads and seal, as opposed to nearly every other commonly used household container?

In: 7899

Answer 1

If it was a one piece contraption, you would be dragging the sealant material (it’s kind of rubbery) over the glass rim as it tightened. This would lead to more cans with a faulty seal and then ruined food.

The two piece set up lets the rotating part tighten down on the lid that remains stationary, so the seal remains intact more often.