Six millimeters, or a quarter inch
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The floor
A nominal diameter of 6 millimeters or greater in the case of items described in metric terms, or a quarter inch or greater in the case of items described in terms of the English system of measurement.
Which is stated twice, once per system
And the two figures are not equal: 6 millimeters is about 0.236 inches and a quarter inch is 0.25.
So the floor depends on how the item is described
An article described in metric terms is measured against 6 mm and one described in inches against a quarter inch.
Which is a small gap with a real edge
An article at 0.24 inches is above the metric floor and below the English one, and which applies turns on the description rather than the object.
Nominal diameter is the measure
Not the thread pitch, not the length and not the head size. The nominal diameter of the threaded portion.
So a long thin screw is below the floor
However structural it looks. Length is not in the definition at all.
And several of this group's articles sit below it
Machine screws, set screws, drywall screws and sheet metal screws are routinely under a quarter inch.
Which means the Act does not reach them
A box of number 8 screws is hardware. Whether anything else reaches them is not addressed here.
The floor is one of four conditions
Article type, diameter, through-hardening and grade marking. All four have to hold.
And a load-indicating washer is the one exception to the type clause
Named specifically, which is why an ordinary flat, fender or lock washer sits outside the definition.
Three of the twenty-eight named articles are those washers
Washer fender, washer flat and washer lock. Excluded unless load-indicating.
So the definition is narrower than the group
Which is the honest reading, and it means a reader has to check their own article against four conditions before any of this applies.
And the container question does not change either way
Sorted, dry, and one lot per jar. The last of those only matters if the Act reaches you.