Question: What are the major ergonomic design considerations for hand tools?
Weight of the tool – Ideally, a worker should be able to comfortably operate a tool without experiencing fatigue or discomfort. The tool’s center of gravity should be aligned with the center of the gripping hand. In other words, tools should feel “easy” to hold in the position it will be used. Use a counterbalance to support a tool that is above recommended weight limits or awkward to use.
Handles – With the exception of tools for precision work, the handles and grips of hand tools should be designed for a power grip.
Handle shape – Select tools that allow you to keep the wrist straight or in a neutral position when using it.
Handle diameter – Handle diameter recommendations vary. In general, cylindrical handles at 1.5 inches offer a better power grip, with a range from 1.25 to 2 inches. For precision grips, a diameter of 0.45 inches is recommended, with a range of 0.3 to 0.6 inches.
Handle length – A handle that is too short can cause unnecessary compression in the middle of the palm. It should extend across the entire breadth of the palm. Handles around 5 inches are generally recommended. Keep in mind that the use of gloves requires longer tool handles.
Separation between handles – Tools such as pliers or tongs are equipped with two handles. The recommended distance separating the handles is between 2.5 to 3.5 inches. Tools with larger or smaller spans will reduce one’s maximum grip strength.
Materials and texture of handles – To ensure a good grip on a handle, sufficient friction must exist between the hand and the handle. Hand tools should be made of non-slip, non-conductive and compressible materials.
Always conduct a risk assessment before making any change. If you would like additional resources or to request ergonomic assistance, please contact your local BWC Ergonomist or request their services on-line at Request a consultation | Bureau of Workers’ Compensation (ohio.gov).
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