Mechanics Stethoscope: A Girl’s Best Friend

Ever since medical school, I’ve appreciated the value of a stethoscope. But it wasn’t until recently that I discovered what a “mechanics stethoscope” is.

The machines we have here in the factory are big and can be fairly intimidating when we hear a new funny noise coming out of one of them. Most of the time we can figure out the cause of the noise pretty quickly and fix whatever’s wrong. But sometimes we’ll hear a noise so slight amidst all the regular noises coming out of the machine, that it’s really difficult to know where exactly it’s coming from.

We had this little whistle coming out of the injection molding machine for weeks. I’d try to explain it to injection mold technicians who informed us that the only thing we could do is wait for the noise to declare itself. That was too scary of a thought. What if the sound declared itself as a faulty hydraulic pump part that we’d have to have specially made and wait a month for?

When someone suggested I try using a stethoscope to pinpoint the source, I thought he was kidding. I couldn’t imagine getting the end of my stethoscope (along with my hand) up in to the crevices of the injection molding machine. Then I googled “Mechanics Stethoscope” and lo and behold, there’s this special stethoscope that has a long rod on the end that’s specifically designed to pinpoint funny machine noise sources. My regular stethoscope cost, I think, a couple hundred dollars. This mechanics stethoscope costs $15 on Amazon (here). Importantly I could get that long probe (not recommended for humans!) into crevices I’d never put my fingers.

Here it is:


It’s actually pretty easy to use. Far easier, I think, than using a regular stethoscope. All you have to do is walk around the machine and stick the probe in to and on to things while the machine is running. Of course you have to be safe and use common sense. Don’t touch wires or moving parts and be wary of moving parts that you’re not touching.

It didn’t take long to figure out the source of the mysterious whistling on the injection molding machine. I could hear the whistle very loud and clear coming from this little thingy that I’m pointing to with the end of the stethoscope:


That rod to the right slides in and out of that thingy. Putting a little bit of grease around that rod made the noise go away. Voila!

So now I like making rounds on all our machines with my new stethoscope, practicing good healthy prevention.

Yep, a Mechanics Stethoscope. My new best friend, pushing Duct Tape, to a still highly respected, second best friend.

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