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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
by criddell 4y ago
> 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.
- inconceivable 4y agomy 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?
- ebruchez 4y agoThat 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."
- crazygringo 4y agoOh 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?
- ebruchez 4y agoI doubt it was for appearance only. Your other reasons make sense.