“Hand problems and Carpal Tunnel Syndrome are just part of the job if you are a mechanic. After all, not many mechanics can last an entire career without developing hand problems.”
It certainly is true that many fleet or plant mechanics, facilities mechanics, gas, electric or water utility mechanics, or others who use hand tools on a daily basis have hand problems. But it is not necessarily from doing the work. It comes from how they use their hands to do the work.
One common risk factor causing this damage that is commonly seen has to do with how people hold hand tools. Certain types of hand grips of pliers, wrenches, screwdrivers, channel locks, and hammers are far more stressful than others.
Partial hand grips is one of these commonly used and stressful hand grips. By definition a partial hand grip involves holding the tool in such a way that the tool ends partway in the palm of the hand. In this picture on the left, the hand is opened so you can see the partial hand grip.
When you hold a tool, your hand generates force to squeeze it. When you push a wrench or push on a screwdriver, if the tool ends partway in the middle of the hand, a lot of stress becomes concentrated on the soft tissues where the handle of the tool ends. This is called contact stress. Just under the skin are the nerves, blood vessels, tendons, and tendon sheaths and they are 
relatively unprotected in the hand. This pressure on these soft tissues can microscopically damage them. Over time the damage accumulates and can become a major problem. The partial hand grip of the wrench in the picture to the right is especially bad because the length of the handle runs along the carpal tunnel and the handle presses deep into the nerves along their length.
Repeated, concentrated stresses from hard surfaces on the palm of the hand will microscopically damage the hands over time. In our body mechanics training workshops we see evidence of this on a daily basis. Tendon damage causes scar tissue to accumulate under the skin and fascia of the hand and bind the tendons, particularly the tendon of the ring finger, to the overlying skin.
Always use full hand grips where the end of the handle ends past the hand and does not end in the middle of the palm when holding wrenches, pliers, and hammers.
Don’t slide the hand down the handle of the tool in an attempt to get more leverage. Use a longer tool instead.
Another important strategy to minimize this contact stress risk is to always wear gloves that protect your hands from contact stress. Leather gloves, canvas gloves, gloves that are a combination of both, and padded gloves are great to help protect your hands from contact stress. Typically cotton gloves or latex, or nitrile gloves offer almost no protection from contact stress.