Reprinted from the ACJ - May, 1995
There is a video game on the market in which a hedgehog traverses a maze of obstacles. He collects rings, neutralizes evil cartoon characters and puts up with a good-for-nothing fox as a sidekick. At certain times he can curl up in a ball and, spinning very rapidly, mow down, through or over most obstacles in his path. Scattering these hindrances into flying bits of video debris, he continues his quest.
It is kind of the same with a bench or hand grinder fitted with a wire wheel. It spins like a whirling dervish and reduces whatever it contacts into small bits of flying flotsam. Auto repair shops use the wire wheel for many purposes: taking burrs off of metal pieces, removing the old solder from a header prior to reconstruction, brushing away corrosion, dirt or lime buildup, or perhaps removing the hardened epoxy from the putty knife or screwdriver that the last guy failed to clean.
For many reasons we take the wire wheel for granted. It is always there and almost never acts up. It won't explode and isn't flammable, but it does have it's own bevy of hazards just the same. We should keep these dangers in the back of our mind, pulling them to the frontal lobe each time we step up and flip the switch.
The chemical concerns are based on the nature of the small dust and particles that the wheel generates. If we are grinding a tin/lead solder coated header, all of the lead poisoning concerns exist. If it is feasible, installation or adaption of a dust collector or exhaust system is an excellent idea. In any case, always wear a dust mask to avoid inhalation of the solder particles. Because these particles can stay airborne and float around the shop, anyone working in the area should join you in wearing a dust mask (not the same one though, it will get crowded in there).
Wash your hands when you are finished and heading for lunch or break. It is not a bad idea to wash up your arms and your face since that dust settles everywhere. I shouldn't have to mention this next point since no one allows food, drink or cigarettes in the lead area anymore, but make sure that the dust isn't coating your coffee cup or dusting your Girl Scout cookies. Not only is the lead in the solder hazardous, but the dust from the breakdown of the wire wheel itself contains iron and nickel. Both can cause pneumonia-like symptoms when inhaled deeply into the lungs.
Nickel has been cited as a possible carcinogen, so wear that dust mask.
The more obvious, and more dangerous, hazards of the wire wheel stem from the physical concerns. Like little Lilliputians attacking Gulliver, the small dirt and solder particles as well as the wires from the wheel itself are sometimes ejected from the spinning wheel and act as small spears, embedding themselves into your skin or, worse yet, your eyes.
Nickel can cause dermatitis, and iron has been shown to cause conjunctivitis (inflammation) of eye tissue and permanent pigmentation (staining) of skin where it has penetrated and is not promptly removed. It's a cheap tattoo, but only an expert can get the flying daggers to spell out "Mother" on your upper arm. If a bit of lead embeds itself below the skin, it dissolves and raises your blood lead level, an odd case of a "skin" route of entry into your body for lead.
So glasses are good, goggles are better and for those of you with pretty faces a face shield over glasses is the best protection. Also rolling down your sleeves to protect your arms is a good strategy. The speed at which the wire wheel spins is plenty fast enough to rub away most forms of dirt, rust and solder. It can also efficiently remove skin, hair and calluses. The resulting injury is less than pleasant due to it not only being a cut, but also a bruise and a burn.
The wheel will nicely insert all the dirt, solder, iron and nickel that we discussed earlier deep into the flesh. Man does it hurt the next day (voice of experience). If this should happen, make sure you clean the wound well, disinfect it and if it is nasty or shows signs of infection go see the Doc. It can be a nasty, lingering injury. Wearing gloves is recommended. But make sure they are tight fitting to avoid our next topic of discussion.
The last and maybe scariest danger presented by the wheel spinning at thousands of rpm's is that if it were to grab your loose sleeves, gloves, tie, necklace, long hair or nose ring, it will pull you in, no questions asked. To avoid taking this close look at the grinder, secure all loose clothing or ornamentation before starting
Also secure and periodically check the tightness of the mounting nut. Whether it pulls you in or it flies off at you, it's no fun to catch a spinning hedgehog square in the forehead at 100 mph.
The above article was written by David M. Brown, Chief Engineer of Johnson Manufacturing Company, Inc. and is published by JOHNSON with the expressed approval of the National Automotive Radiator Service Association and the Automotive Cooling Journal. Other reproduction or distribution of this information is forbidden without the written consent of JOHNSON and NARSA/ACJ. All rights reserved.
JOHNSON MANUFACTURING COMPANY
114 Lost Grove Road / PO Box 96 / Princeton, Iowa 52768-0096
Phone 563-289-5123 or Fax 563-289-3825