Products to be held in the hand should have appropriate heft and balance. For instance, consider a cordless power tool. The grip should be comfortable, not too big and not too-small. Also think about weight. Is the object too heavy or light? Weight can affect the impression of quality. Heavier might come across as substantial, as in heavy duty. Lighter might be interpreted as high-tech or convenient.
Likewise, an overly light tool might make users employ too much force and damage the tool or hurt themselves. And a tool that is too heavy will probably make users wear themselves out using it. In addition, avoid sharp edges where users hold objects. Little, sharp ribs might look cool but will only end up hurting users' hands.
Also, place controls in a well thought-out manner. This can make or break a product. For instance, controls for one handed use had better be easily accessible by that hand. And products for the extremely old or young need bigger buttons and switches. These groups of users often fall short in the areas of eyesight and manual dexterity.
Last, but not least, is safety. Design products to prevent inadvertent injury. A good example comes from a Colt 1911A semiautomatic pistol I once assembled. I was amazed at how many different safeties the gun had to keep it from accidentally discharging. These included a safety near the thumb, and one you had to push out of the way of the trigger mechanism. A safety on the back of the grip made sure you held the weapon in the prescribed way. The designer thus forced end users to be deliberate.
This article was edited by Leslie Gordon. Mike Hudspeth is an industrial designer with more than two decades of experience.