Cutting Tool Engineering
May 2011 / Volume 63 / Issue 5

Don't take hearing for granted

By Michael Deren

I’ve been having hearing problems the last couple of years, so I recently visited an ear, nose and throat doctor to get checked out. He quickly diagnosed the problem as tinnitus, which, according to Wikipedia, is “the perception of sound within the human ear in the absence of corresponding external sound.” Common symptoms include ringing and static noise in the ears.

Tinnitus can be a side effect of natural hearing impairment (aging) or use of certain medications. It can also be caused by noise-induced hearing loss. I’ve been in manufacturing for almost 35 years. You can probably guess which one caused my impairment.

My next visit was to an audiologist to determine the extent of my hearing loss. After a battery of tests, the doctor determined I had hearing loss in both ears, which came as a surprise. There is no definitive percentage loss, but a range of loss. My left ear has mild to moderate loss. This means that ear has trouble hearing subtle sounds, such as leaves rustling and a clock ticking. My right ear, on the other hand, has moderate to severe loss. This means that ear also has trouble hearing more pronounced sounds, such as a faucet dripping and normal conversation, making it difficult to hear when there is background noise.

Tinnitus doesn’t happen overnight, but over time. During my early years in manufacturing, hearing protection wasn’t an important consideration even though noise was part of the job. At my first shop job, screw machines and turret lathes noisily cranked out fittings. Another place had a “friction” saw, with a blade that was at least 6 ' in diameter. It cut mill bundles while kicking up sparks 20 ' to 30 ' high. Because the saw’s screeching noise was so unbearable, I couldn’t tolerate being within 100 ' of it when it was operating. The operators wore industrial hearing protection, but the rest of us just covered our ears.

When I started operating machine tools, hearing protection became more readily available, but was not commonly used. If I wore hearing protection, I couldn’t really hear if the cutter was working correctly, so I removed the protection from one ear to get a better listen. Can you guess which ear I used mostly?

Over the last few years, improved ear protection has become readily available. More importantly, most shop people now use hearing protection when they’re at their machines or passing through high-noise areas. Where I work, you can’t walk 100 ' without having a station for hearing plugs.

For younger workers, periodic tests will help them to recognize any hearing losses sooner and head off severe losses. As for me, the prognosis is hearing aids. I’ve opted for the type that hangs behind my ears, with a clear tube that enters the ear.

The device provides programs for different situations. For example, there’s a program for normal conversation and one for a noisy environment. It’s all well and good, but I would rather have my own hearing again. It’s too late for me.

According to the U.S. Bureau of Labor Statistics, occupational hearing loss is the most commonly recorded occupational illness in manufacturing, with 17,700 out of 59,100 cases in March 2010.

When I was young, I didn’t really think about the hearing damage that noise can do. Now, I can’t hear or understand everything my grandsons say to me and have difficulty hearing my wife while she’s washing the dishes or we’re driving in the car. I miss having conversations without having to lean over with my “better” ear. Take advantage of every opportunity to protect this sense because once it’s gone, it’s gone. CTE

CTE04 SSMACH About the Author: Mike Deren is a manufacturing engineer/project manager and a regular CTE contributor. He can be e-mailed at

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