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Comment by crazygringo | Hacker News Reader

Putting aside the bizarre fact that the creator is selling these without having tested them (?!)...

I'm genuinely curious if a plastic version of these balls actually works as anything more than a toy? If plastic will quickly wear out unlike the original metal, or if the lesser weight of the plastic has any undesirable side effects?

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> unlike the original metal

The correction at the bottom seems to imply that the originals were not metal.

> Correction: IBM's Selectric balls aren't made of metal.

That is correct. IBM type elements are made of plastic, but plated with a very thin layer of metal. From a 1981 article: "the type element was functionally plated using an electroplating process that enabled the metal skin to adhere to the plastic with tremendous tenacity. Even when the plastic contracted at a temperature of -75C, the metal skin did not break off. Selection of the plastic involved extensive tests on no fewer than twenty-five types of plastics for impact strength, resistance to acids, shrinkage, and molding adaptability."

Oh fascinating, thank you.

I wonder then if the metal was just for appearance (looks more expensive), or if it contributed to the longevity of the type ball, or if it improved how the ink transferred to the page?

I doubt it was for appearance only. Your other reasons make sense.

my parents had a selectric which i used as a kid... iirc, the ball had some weight to it, and a metallic finish -- maybe there was a lead weight or something inside of it?

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