Three steps to more comfortable hand tool use

Hand tools don't have to hurt your body. Take these steps to improve your job's ergonomics.

by Kay Falk

“In studies of thousands of workers, we found that carpal tunnel syndrome is much more prevalent among construction workers, and they generally don’t report it or visit a doctor until they start dropping tools and can’t use their hands well. When they do finally seek help, surgery may be their only remedy,” says John Rosecrance, assistant professor at Colorado State University.

Hand tool manufacturers used to design tools only to get the job done effectively. Today, they are improving designs to reduce damage to your body. But you can do more to reduce the risk of repetitive motion injuries.

Step one: Choose tools wisely
Not all tools that are labeled “ergonomic” truly are and one that is “ergonomic” for one user or task may not be for another. There are no truly defined ergonomic guidelines, so you must try many tools until you find one you like.

To help in your search, follow these hints Anwwad Dababneh and Thomas Waters reported in Applied Occupational and Environmental Hygiene:

• Grips: Look for finely textured surfaces that offer a more secure grip than smooth or slippery surfaces. Grips coated with semi-pliable (not too hard or too soft) material can distribute contact pressure and isolate vibration. They also insulate the hand from a cold gripping surface that reduces blood circulation in the hand. Avoid deep ribs and grooves on the grip surface which create pressure points on the hand. They can cause discomfort or rapid fatigue.

For optimum tool use, your fingers should gently curve inward, not forced to be fully straight or tightly curled. The tool grip or how you use a tool shouldn’t make your wrist be continually bent up or down, or toward your thumb or little finger. You want your wrist in-line with your forearm.

The length of the grip should be long enough to allow you to use a closed-fist grip formed with all your fingers and thumb (called a power grip). Grip length should not be longer than the width of your palm, or 5" to 6". If you wear gloves, allow for another 1/2".

• Handles: Avoid sharp or non-round edges. Oval or rounded-edge rectangular handles are more comfortable than round ones. Avoid handles with ridges that separate your fingers. For screwdrivers, select circular or rounded-edge hexagonal handles.

For one-handle tools, like hammers and saws, the handle’s cross-section should allow your thumb and index finger to overlap by 3/8".

For two-handle (pliers-like) tools, you get maximum grip strength when the grip span of the handle is between 2" fully closed and 3.5" fully open.

Select tools with a pistol grip or in-line tools and avoid tool and work situations that force your wrists to be bent awkwardly. Avoid elevated shoulders or extended elbows.

A bent or adjustable angle from the handle to tool action point can help you keep your wrist straight.

• Handedness: If a tool can be used in both hands, you can switch hands to give your dominant hand and wrist a break. Avoid tools meant to be used by one hand and not the other. If you can’t, choose tools matched to your preference for right- or left-handed work.

Step two: Think about what your body is doing
When you’re using a hand tool, it’s the combination of ergonomic stress factors that can add up to pain and injury to your body.

Unnatural positions and repetition cause stress. Awkward postures, holding your hands too high or too low, bent wrists and excessive muscle force are all unnatural positions. Taking breaks or varying your activities are the best ways to minimize physical stress from tool use.

Step three: Take action
Construction workers know what makes them hurt. Encourage workers to speak up about aches and ask for ideas on how to improve working conditions.

Published in the May/June 2003 issue of Contractor Tools and Supplies magazine.

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