The little things that count

Who would have thought something so seemingly insignificant as a loose screw could scuttle a space walk?

Yet, apparently that's exactly what happened on the orbiter Columbia during shuttle Mission 80.

Aviation Week and Space Technology reported December 16, 1996 that a loose screw in the gearbox of the extravehicular activity hatch jammed the hatch so astronauts couldn't open it and perform two planned space walks.

While the public at large may be surprised at the impact such small components can have, engineers know differently. Indeed, it's the little details that often make or break a project or a product. For example, in this issue we report on Goodyear's new line of synchronous drives--the Eagle Pd drive system--that cuts noise, energy consumption, and maintenance costs. The enabler: a simple change in the shape of the teeth to a helical design. Here are a few other examples of where details made a positive difference:

In the Kodak Advantix Camera, engineers trimmed one part 0.25 mm to ease the opening and closing of the film door, and cut the rise of a detent by a few thousandths of an inch. ("Picture-perfect engineering," Design News, May 6, 1996).

Item: The new Silicon Graphics Origin2000 uses a special screw and cam to enable a card to slide directly and easily into a slot that offered only three thousandths of an inch clearance. ("Building a workstation, block by block," Design News, January 20, 1997)

Item: In the new Bang & Olufsen BeoSound 9000 CD player, engineers relied on tiny servo systems, microprocessors, dc motors, digital-to-analog converters, and 15 IR sensors to assure world-class sound. ("CD player looks good inside and out," Design News , September 25, 1996)

In each case, breakthrough enginering relied on subtle and deceptively simple design changes--the kinds of things that never make the evening news. And, readers, no doubt, can cite hundreds of similar examples from their own design experiences.

The public often associates grand innovations in products with spectacular, large-scale design breakthroughs, and often the public is right. But, as these examples show, the small things--the details and fundamentals of design--are where the action is in engineering.