August 26, 2008
Operating an angle grinder is a tough job. Find out what angle grinder manufacturers are doing to make the tools more user- friendly, including lightening the weight, enhancing antivibration measures, and improving safety.
An angle grinder may not be the most important piece of equipment on the welding shop floor, but don't underestimate its effect on those who use the tool. Powerful, heavy-duty grinders can be just that—heavy, causing fatigue. Tough applications can result in heavy vibrations emanating from the tool, which in the long run can cause musculoskeletal disorders. And let's not forget the danger associated with using such high-powered equipment.
The Occupational Safety and Health Administration (OSHA) recently released its"Guidelines for Shipyards," which, among other things, details how the use of power tools such as angle grinders may result in pain, numbness, increased sensitivity to cold, and a decreased sensitivity to touch in fingers, hands, and arms. Whole-body vibration exposure may damage joints of the skeletal system.
Angle grinder manufacturers understand this and are faced with the challenge to make the tool lighter, safer, and more comfortable to operate without sacrificing the power that job shops expect from these machines.
Grinding jobs and vibration go hand in hand, but grinder manufacturers today are cognizant of the dangerous effects that vibration exposure can have on an operator and are taking measures to minimize vibration and increase user comfort.
In Europe, for example, vibration levels determine how long an angle grinder can be in operation. The higher the vibration levels, the less time a grinder can run. In the U.S., however, no such regulations are yet in place, but Terry Tuerk, product manager at Metabo Corp., said OSHA's new guidelines could be a sign of changes to come.
"If OSHA comes out with a guideline or a suggestion and they find out that the industry isn't following it, that's when they come out with their regulations saying that you must [follow it]," Tuerk said.
Metabo tackles vibration in its angle grinders with an antivibration side handle, which reduces the vibration an operator feels by up to 60 percent, Tuerk said, and extends the amount of time the operator can hold the tool without fatigue or getting a buzzing feeling in his fingers.
"[In Europe] our angle grinders without the antivibration side handle, for example, can be run for only two hours per day. With the antivibration side handle, a user can run the tool for six hours per day," Tuerk said.
Tuerk also mentioned the possibility of integrating other antivibration technology, which would deflect away from the operator vibration created by the grinding wheel and counterbalance any out-of-balance situation in the grinding wheel.
"It's very close to becoming a reality in Europe, and we have not yet made a decision to have it come into the U.S., but it's a possibility should regulations go into place here," Tuerk said.
Bosch Power Tools also has equipped its angle grinders with an antivibration side handle on its small and medium grinders and antivibration side and main handles on its larger models. Ryan Anderson, product manager at Bosch, said vibration on the large models is reduced up to 70 percent because vibration is addressed at both contact areas. A separation point on the tool body also helps to minimize vibration.
Both Anderson and Tuerk agree that because Bosch and Metabo are based in Europe, it helps them stay ahead of the game as far as technology advancements in the industry go.
Ernie Leopold, manager of metalworking products at Fein Power Tools, said there is always going to be some sense of vibration. External factors such as the balance, or lack of balance, with the abrasive will have a direct effect on vibration. Using antivibration/fatigue gloves is the quickest way to resolve the problem, especially when using older machines. Fein, also a European manufacturer, is well aware of European standards. However, said Leopold, the company addresses vibration through the manufacture of the tool.
"It's a precision-made tool; armatures and other internal parts are precisely balanced, and gear heads are machined to strict tolerances. This helps to eliminate vibration and extend tool life," Leopold said.
Grinders can be heavy, especially after holding the tool for hours at a time and performing repetitive movements. Manufacturers are faced with the task of making grinders lighter while still providing the power characteristics that users need.
Leopold said only so much can be done to minimize the weight of an angle grinder and still maintain quality and durability. The technology is available to do so, but it wouldn't make the tool very cost-effective.
"You can go to some space-age products like carbon fiber, composites, or lightweight alloys for gears and gear heads, but then, obviously, that increases the cost of the tool," Leopold said.
Few technology advancements have been made to angle grinders over the years, but Fein hopes to address that with a new angle grinder product line expected to hit the U.S. market in the near future.
Metabo's new line of angle grinders are smaller and lighter than the previous line and allow the operator to grip the tool at the front or from the back. The back end has a larger diameter, making it easy for the operator to grip.
"We studied the market and found that most users doing light grinding or sanding like to hold the tool toward the front end. If they are doing aggressive grinding, then they hold the tool toward the back end," Tuerk said.
Bosch Power Tools' medium-size angle grinders were developed to create the feel of a small angle grinder with the design of a large angle grinder. Features like the spread-out grip area and a trigger-style switch are reminiscent of the features found on a larger model. The weight, at a little more than 5 lbs., is half that of a large angle grinder. The feedback so far, Anderson said, has been positive.
"Users love it. You're getting rid of all that weight and creating a smaller, more compact model."
Job shops typically have a lot of tools, and angle grinder manufacturers are finding that the fewer tools necessary for maintenance, the better. Anderson recalled job sites restricting certain types of tools for safety reasons.
"Some job sites won't allow some tools because people trip over them or they lose them. We want to eliminate the need for those extra tools," Anderson said.
Bosch has gone toolless with its attachments, and the company's tool-free adjustable guard, for example, allows a user to slide the guard in any direction by pulling a lever. When the lever is released, the guard automatically locks securely into place, preventing it from spinning.
"If the guard is in your way at a particular time, it's really easy to adjust," Anderson said.
With Metabo's toolless wheel change system, the nut disengages itself by a half-turn when the spindle lock button is pushed while the wheel is spinning down. This eliminates the need for a spanner wrench and simplifies the process of changing grinding wheels.
"The Quick system helps loosen the nut for the operator so it can be turned off by hand. The grinding wheel can be replaced, and the nut can be spun back on by hand, allowing the operator to get back to work," Tuerk said.
Safety in Fein's grinders starts at the motor, which is soft-starting, allowing it to ramp up slowly instead of immediately turning on to full power. This prevents recoil or jerking when the tool is switched on. Motors also provide constant speed and maintain RPM and torque when adding pressure and bearing down on material.
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