[margalabargala]

They are not microscopic! I can easily see the balls in the tips of ballpoint pens.

[OneDonOne]

The ball is not microscopic, but the tolerances required to make the ball spherical and fit into the socket are.

[margalabargala]

Exactly, so this sentence is incorrect:

> Ballpoint pen tips are microscopic tungsten carbide ball held inside ultra-thin steel sockets

[OneDonOne]

Yes indeed, you are correct. My mistake.

[jurgenburgen]

The BBC article even mentions that they are milliscopic, not microscopic.

> 2.3-millimetre