Before the Industrial Revolution and the concept of mass production, tools were more “ergonomically” correct than those used today. Back then, tools were usually designed and produced for a specific user. With the introduction of the assembly line and mass production, tool design was limited by production capabilities. Today’s tools are mass-produced and designed for the non-existent “average user”. This means they fit most people somewhat, but no one particularly well. There is also a similar lack of fit between the way the tool is designed and the way it is used. Most tools today are designed to do a multitude of similar tasks adequately, but none optimally.
Since individual tool production is not an option, the main question a tool buyer should ask is: Is this how I would have made the tool?
Things to consider when selecting and/or purchasing a tool, either for on or off the job use, are:
Does the tool make me do more work than necessary?
- Power tools require less exertion on the part of the user.
- Lighter tools require less exertion. Heavier tools should be suspended and counterbalanced.
- Spring-loaded tools require less exertion as the spring opens the hand vs. the hand opening the tool.
- Tools that do not waste motion (saws that cut in both directions, for example) require less exertion.
- Poorly maintained tools require the user to work harder. Replace worn tips, bits, and sockets and sharpen dull cutting tools.
Does the tool fit my hand?
- Handles should be made of compressive, non-slip material. The soft, visco-elastic material found in commercial tool wraps (also called Grip Kits) add a compressive layer to a tool’s handle increasing the total diameter, allowing it to take the shape of the user’s hand.
- Handles should span both sides of the palm to avoid pressure on the collection of nerves and soft tissues in the palm. For most users, handles should be at least 5-in. long.
- Handles that fill the palm distribute force over a broader area. A diameter approximately 1.5-in. to 2-in. is desirable.
- Grip strength is greatest for most users at a grip span between 2.5-in. to 3-in.
- Triggers should be at least 2-in. long so they can be activated using multiple fingers. Single-finger triggers encourage the development of “trigger finger”, a repetitive stress injury that can be painful and is characterized by clicking, snapping, or locking of the tendons in the affected finger.
- Sharp edges do not fit the contours of the human hand and can create pinch and pressure points.
- “Finger grooves” show that the tool was made to fit a hand, just not your hand, and should be avoided.
Does the tool fit the task?
- Tools should be oriented for use with a neutral wrist posture.
- In-line and pistol grip options should be available for drivers and used in the appropriate situation.
- Many bent handle tools are now available for specific jobs and should be used to avoid wrist deviation.
Any tool can be labeled “ergonomic” by the manufacturer, but by taking a minute to think of how the tool will fit the user, the task, and its orientation to the task, you can decide for yourself. To further assist in evaluating tool options, refer to the Cal/OSHA NIOSH Guide to Selecting Non Powered Hand Tools. A Spanish version is also available from Cal/OSHA (scroll to the “Ergonomics” heading).