Terry McDonald: Site Safety

Cutting tools are sharp by their very nature, but they present potential dangers far beyond that of edge exposure. Here are additional points to consider.


It’s been awhile since we discussed the safety issues surrounding cutters, blank parts, and cut parts. There are a number of potential dangers involving these peripheral components of gear cutting that are often overlooked when safety concerns are discussed. First we’ll look at the cutters.

Whether they are hobs, shaper cutters, thread milling cutters, single position cutters, or any of the multitude of variations of these, by definition cutters are very sharp. Even when any of them are “dull” by material-cutting standards, they are still quite capable of slicing human flesh. Therefore, when handling any of the myriad cutting tools used in the gear industry, it is of the utmost importance that they be handled correctly. First we must make sure that the tool is cleaned of chips and coolant residue prior to handling them. And even though it isn’t a bad idea to have the proper protective gloves available for this chore, we must insist that the operators do not wear gloves of any sort when working around, or with, any moving spindles or gears. I have seen too many cases of gloves getting caught in rotating items that, in addition to causing harm to the wearer, can cause damage to the machine.

Another danger associated with cutting tools also relates to the sharpness of the item. “Dull” cutting tools create excessive force by being fed into materials at the same feeds and speeds as when they were sharp. This practice will not only produce parts that are not up to your standards, but also present the very real possibility of failing in a mode that presents excessive danger to your employee. We have all heard of or even seen cases where cutters have literally come apart in use and pieces have been thrown which, of course, can cause great pain or even fatalities. It is extremely important to keep your cutting tools sharp, and not only from a production standpoint but also as a safety factor.

Storage is another safety issue that is often neglected when it comes to cutting tools. I can’t believe the number of gear shops I have visited that have cutting tools hanging from nails on the wall, stacked on shelves without being in containers, just laying about on tables, or even on the floors. This is not only detrimental to the cutting tools, but it’s an accident just waiting to happen. The cutting tools we use in this industry are expensive, and the way they are treated seems to be an anomaly. We need to keep the tools in the container they came in or in another protective container, not only to protect our employees but to protect our investment as well.

Even prior to gear cutting, blank parts can be dangerous in many respects. They can have burrs from previous operations, they can be covered with oil and slippery, they can be heavy, which makes them difficult to load and unload into the machine, or they can be of a form that makes them difficult to handle. All of these situations require that we as employers closely monitor how the blanks are handled to minimize the hazards to our employees. We must make sure that adequate measures—such as having deburring, cleaning, and lifting mechanisms readily available—are taken so that these risks can be avoided.

These blank parts still have the same dangers after having the gear teeth cut, plus there is the added hazard of the burrs and chips created during the cutting process. Again, we must take steps to address these issues before they become an injury. I hope that this little reminder has brought to light some areas where you can improve safety conditions for your employees, and for everyone who enters your shop. 

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is partner and manager of Repair Parts, Inc., and a current member and past–chairman of the American National Standards Institute B11.11 Subcommittee on Safety Requirements for Construction, Care, and Use of Gear Cutting Equipment. McDonald writes this monthly column specifically for Gear Solutions magazine, and he can be reached at (815) 968–4499 or rpi@repair–parts–inc.com. The company's Web site is [www.repair–parts–inc.com].