Flexibility-Usability tradeoffWith great power comes great responsibility

The more flexible a systems is, the harder it is to use, but easier to use systems are often less flexible.

A CnC router seems like a highly flexible tool. It can cut any shape you might imagine. But is it useable? Is its function obvious, how much training does it require to load a file, or to design a file? Can it be explored by a novice? Can a visually impaired user easily operate the visual design programs that drive it? The flexibility of a CnC comes at a cost of how useable it is.

Combination tools can be a fantastic option for people with limited space, and are capable of producing excellent work. But combination tools like a jointer, planer, shaper, table saw, might best be avoided when teaching groups of visually impaired students, for a few reasons.

For one, the set up and breakdown times are disengaging for anyone who cannot watch. The primary benefit of a multi-tool is that you only need one machine. But when all of the work takes place on one machine, students must stand in line and wait for their turn, which is not helpful for non-visual learners. Another problem is that flexible tools are hard to use, because switching them between uses can throw them out of calibration. This causes boredom as the machine is reset.

The biggest problem with highly flexible tools is that their flexibility tends to obscure their purpose, which impacts usability. Consider the two tools in the images below. The first is a multi-tool with no perceivable use. It is complex because its functions are many, but that makes them obscure, and therefore it might be less useable in practice.

This tool is multi-functional, and ideal for a limited space. But that comes at the cost of being obscure, and having breakdown and setup times that can create lineups and interruptions.

In the next image is a chop saw. The function is easy to perceive by sight or feel. The blade is obvious and mounted to the only moving part, which only moves in one axis. The handle and the button are one part, connected to the moving part, clearly suggesting how to operate it, and what it will do. Its use is singular, and consequently obvious with a glance or a touch.

The chop saw has a 10-inch circular blade connected to a handle. The handle pulls the blade down. It has only one use, so it is not flexible, but that use is simple and immediately obvious.

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