HP 41C Manual vs HP 41CX

[Eric Rechlin]

(10-26-2024 06:52 AM)Steve Simpkin Wrote:  Edit: HP was still using wire binding up until at least the early 1990's. Here is an example of the HP-48SX handbooks.

That is a spiral binding, also known as coil binding, not a wire binding, even though it is made with a wire. Notice how the metal spiral is coiled up. Spiral bindings can be either metal or plastic. If I remember right, HP only used metal for their coil bindings, though most third-party spiral-bound books for HP calculators used plastic instead. Plastic spiral bindings are especially durable and easily removable and replaceable, whereas metal spiral bindings can be flattened and deformed if compressed too much but usually have easier-to-turn pages due to less friction.

The other one you pictured (and the one that was graphically represented by a drawing in Thomas's link) is indeed wire binding, which does not form a coil. It's basically the metal equivalent of comb binding (which uses plastic and is sometimes mistakenly referred to by the trade name "GBC"), in that it is held open by a machine, the pages are put in, and then it's forced to (or allowed to, in the case of comb binding) close shut. The advantages of a wire binding are it's more durable and smoother-opening than a comb binding; the disadvantages of it are that it uses more expensive equipment to open and close and that is easily deformed if you try to open or close it by hand.

The easiest way to tell the difference between a metal coil binding and a metal wire binding at a distance is to look if the wires are doubled through each hole or perfectly perpendicular to the spine of the book -- then it's wire. If the wires only go through holes individually and are at a slight angle to the spine of the book it's a spiral/coil binding. A coil/spiral binding looks like a spring when removed from a book. A wire binding looks like a mess (unless you are very careful).