Golf Ball (IBM Selectric)
Definition
Spherical typeball developed by IBM in 1961; rotates and tilts to bring the chosen character to the print position. Class link to Selectric machines.
- Introduced
- 1961 by IBM
- Shape
- Spherical typeball
- Mechanism
- Rotates and tilts to position the character
- Forensic use
- Class characteristic linking typescript to Selectric machines
Common questions
How does the golf ball element differ from a traditional typebar mechanism?+
A typebar machine has one metal arm per character that swings up to strike the ribbon, while the Selectric's single spherical element rotates and tilts to bring the needed character to the printing point, eliminating jamming type bars and giving a distinctive uniform strike pattern.
Why is the golf ball only a class characteristic rather than individualising?+
Because the element is a mass-produced, interchangeable part shared across many machines, matching a typescript to a specific ball design narrows the search to that class of machine but does not by itself identify a single machine.
What individualising features can still link a typescript to one specific machine?+
Wear patterns, alignment defects, ribbon condition and platen damage accumulate uniquely on an individual machine over use and can be compared against exemplars to move from class-level to individual-level identification.
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