Tuesday, October 16, 2012

Brushes Earplugs and Air hoses

Tomorrow I go for my twice a year hearing test. Into the booth to sit there straining to hear something I know is there but sounds like silence and the ringing of my tinnitus. I already know what the conclusion will be as the cheery nurse practitioner tells me, "Did you know you have significant hearing loss on your right side?"  This has been going on for quite a few years. I have chosen an occupation that carries some risk of long term noise exposure if your not careful. What happened to me is preventable for sure so I write about it to try to help a younger guy that is on a similar path. I guess I have finally made the big time since I'm hard of hearing like all the old crotchety metalworkers I learned from.

When I worked exclusively out in the shop I started wearing ear plugs early in my career. It took some getting used to but after the initial break in period even the sound of a MIG welder was painful to my unplugged ears and I couldn't work without them. My hearing problem started when I transitioned into the front office of all places.

An office is not what you would consider a high noise hazard area. In fact its downright quiet compared to the shop. I always thought the engineers that complained about the noise were big babies and they should try a few hours at the point of noise generation to get them calibrated to some real noise. When I moved into the office and started designing and doing more quiet engineer type work there was a subtle shift in the way I protected my hearing.

So in the old days you started the morning and put your ear plugs in and didn't take them out until lunch time. I was natural since you washed your hands for lunch and could use the same plugs afterward. When I moved into the office and was still keeping my hand in the shop work the all day system really didn't work. I might be out in the shop doing something on one of the machines when I would get a phone call or have to go to a meeting which meant I needed the ear plugs out. This pattern of interruptions is typical of a working foreman splitting time between the office and shop. Back and forth all day long between the shop and the office which have very different hearing protection needs.

What happened to me was that after a few thousand interruptions it became more practical to leave out the hearing protection. This is a self fulfilling cycle. As you begin to damage your hearing the need for hearing protection seems less acute. Louder noises become more tolerable. It is a slow process that is insidious and unrepairable. The shame is its really preventable. It happens so slowly I never noticed it until I had lost a good amount of range on one side.

Many years ago an old timer told me to never use an air hose on a machine. I listened and took his advice until I worked in my first job shop. Boy, a good air hose takes a fraction of the time to clean the machine or sweep under a bench than a silly paintbrush does. Job shops are about making money and moving fast so if you can clean your machine and be ready for the next job in a tenth the time then I think you know the answer. In a job shop machines are commodities which is the opposite of the toolroom or home shop where time and production is not the biggest factor. If you wear out your machine because you used it a lot including the abuse of blowing it off with an air nozzle but made the boss money in the process then you get a bigger newer faster machine with the same air nozzle and more work.

Air hoses at high pressure work better than air hoses at lower pressure. Simple physics. They also make a lot more noise. If you are wearing hearing protection the risk is fairly low even in a noisy environment and using blowguns. Unprotected you are almost guaranteed to be heading for a problem later in life. When we moved into our shop space my wife was very concerned about noise from air hoses and compressors since right next door to her studio is my machine shop and the main guy using it is already impaired. Her concerns are real.

I plan on a nice quiet compressor in the future so I can run some of my air tools but currently only have a little hobby compressor that's not really suitable for blowing off machines or running air tools. In the interim we have been enjoying the relative quiet in a shop sans compressor. I can even hear the radio while I work.

I improved my efforts at hearing protection by changing a few things around the shops I spend time in. It is important that they are still flexible enough for my work style and duties otherwise its easy to skip. The first thing was to go after the worst offenders, unregulated air hoses. We added regulators to all the air lines with dedicated blowers on the ends. After some testing the set pressure ended up around 35-40 psi to the blow gun. This makes a huge difference in the shop. It takes a little longer to clear off a machine when you have a lot of chips on it but the reduced sound level is worth it. Our scientific support shop doesn't do any production work so we really don't count seconds of cycle time in the jobs we do.
The second thing that has helped is buying multiple sets of comfortable high quality ear muffs. It took a few tries to find a set that fits me well enough to make me want to use them. I have found if I'm not more than a couple of steps away from a set I'll use them automatically. Sounds pretty simple right? This allows me the flexibility to switch between normal conversation and phone answering mode to machine operations without having to wash my hands to re-insert ear plugs. I have them on all the worst noise making machines in the shop like the belt sander and chop saw. In a small shop four or five pairs in strategic locations make it easy to do the right thing for your hearing.
Of course if its hot, or I will be wearing hearing protection for a long period of time the roll up foam ear plugs are still my favorite.
The second thing is I finally found a decent chip brush that holds up to machine shop abuse. For years I have tried all manner of paintbrushes and wisk brooms with generally poor results. My new favorite brush is made by the Gordon Brush Company  Lucky for me that McMaster sells their brushes individually otherwise I might have been reluctant to test these out of I had to buy a dozen on spec from the manufacturer.
These purpose designed tee slot brushes work great. The polypropylene bristles don't get permanently bent over and shorten the useful life of the brush. I don't care for the metal slot cleaner since I keep all my slots clean as a whistle. The metal slot cleaner just seems to get in the way when you use it while machining.
These high quality brushes have just the right amount of stiffness to dislodge the oily chips but still have a fairly light touch. Narrow enough to fit between the vise jaws when they are close together I can use them for many of the operations I would have normally just blasted with the air hose. Even with all these brush improvements there is still a need to blow things off with air or some other gas jet. I mentioned that I don't have a good compressor in my home shop just yet. The one I do have is basically a little machine that converts money in the form of electricity into pure noise with a meager output of air as a consolation prize. As part of a recent carburetor rebuilt I really wanted to blow some air through the small jet passages to clean them out. My wife was home so I was reluctant to fire up the compressor from hell and force her to wear earmuffs while I made noise. I remembered a can of compressed air I had like you would use to clean electronics with. As it turns out this worked better than the compressor could hope to. It had a nice small diameter straw with it that reached into the intimate recesses of the carburetor more easily than any air nozzle in the shop.
It is definitely more expensive than compressed air out of an electic compressor but it sure is quieter and more importantly didn't bother my wife. Being expensive makes me want to conserve it and only use it for things that really need a precision blast of gas. We switched to a new type of high volume blowgun. Acme Typhoon is the type and they work quite well. The air volume is impressive with a selection of available tube lengths. We tested the shortest and a twelve inch length and seem to have settled on the longer tube. The grip is cushioned and at a ergonomic angle.

So folks out there reading this do yourself a big favor. Learn from my mistakes and find a way to work a good hearing protection plan into your shop operations.


  1. “So folks out there reading this do yourself a big favor. Learn from my mistakes and find a way to work a good hearing protection plan into your shop operations.” You’re right. There is always a way to work things out for the betterment of a situation. It’s good that you made an effort to improve the protection of your ears. After all, the ears are one of our possessions that will be hard to replace.

    Darren Mcandrews

  2. Hi Darren,

    Thanks for the comment.