Using an Angle Grinder Safely

An angle grinder is an invaluable tool in the home workshop with a multitude of uses. As the name suggests, it can be used for grinding metal, stone, plastic and timber but can also cut these materials as well as slates and building tiles. Angle grinders use a disk of abrasive material spun at a high rotational speed by an electric motor in order to perform the cutting action.

All work environments need to be safe but when using a power tool, a trip or fall can result in a serious accident. Tools are often driven by powerful motors or engines and the business end of the machine can be an abrasive cutting disk, a blade with sharp teeth or a sharp drill bit. As the saying goes "flesh is no match for steel" and safety is paramount.

So here are some tips:

• De-clutter your workspace. Tool boxes, scattered tools, lengths of steel and timber and power cables can cause trips and falls. Keep everything to one side where it can be accessed if needed.
• Illuminate your workspace adequately. Proper illumination using background lighting and a floodlight ensures that you can see what you are doing and don't have to strain your eyes. This is especially important when using goggles which can somewhat obscure vision if they become fogged or dusty. Personally I find a head torch is great as it directs a beam of light exactly where needed.
• Power cables and flexes. Keep these behind you so they can't end up getting cut or tripping you up
• Provide adequate ventilation. Grinding and cutting will produce dust and metal particles, sparks and fumes. Open doors and windows and try to direct sparks away from you.
• Flammable materials. Remove gasoline(petrol), diesel, gas cylinders, solvents and other flammable materials from the work area. If this is not possible, direct sparks away from these items. Paper and oily cloths are also a fire hazard.
• Rain and water. Don't work during rainy weather or use a tool which has become wet without drying it thoroughly. For added safety, power the angle grinder from a socket or extension lead fitted with an RCD (ELCB) adapter.
• Jewelery and loose clothing. Remove jewelery and bracelets and loose clothing such as scarves and anything else which could possibly get caught up in the rotating grinder disk and shaft.

Safety clothing should be worn to protect your hearing, lungs, eyes, hands and feet from injury.

• Eye protection. Safety goggles need to be worn to protect eyes from flying particles and sparks. These should be to EN166B standard. Alternatively use a visor. The advantage of a visor is that it is less likely to fog up which often happens with goggles.
• Ear Protection.Muffs or ear plugs will lessen the risk of hearing damage
• Hand protection. Gloves will give protection from sharp, hot or flying pieces of waste metal
• Breathing protection. Use a suitable dust mask to protect against fumes and dust particles. This should seal properly around the face.
• Footwear. Wear steel toe cap shoes or boots with good grips. If you are working with heavy items which could drop when cut up, this will protect your toes.
• Overalls and Leather Apron. These protect clothes from sparks. Watch out for sparks falling into pockets or turnups.

An angle grinder like any power tool should be maintained in good condition and given a quick inspection before use. Check out the following:

• Flex and Plug. The flex should be securely attached to the tool and plug. Exposed cores in the flex at these points should be sorted by rewiring the plug or grinder. Damaged flexes should be replaced.
• Check the Guard. The guard on an angle grinder is an essential component which should be in place at all times. It protects the user from sparks thrown upwards and backwards and also takes the impact if the disk shatters by deflecting chunks of material downwards. The guard should be adjusted on the grinder to the correct angle, giving maximum protection by deflecting sparks and disk fragments towards the ground.
• Side Handle. This should be tightly screwed into the tool.

Use the proper disk for the job and check it for any cracks, missing chunks or other defects. Never use a damaged disk which could potentially shatter and throw out fragments at high velocity. Disks are broadly divided into cutting and grinding disks. Cutting disks are used for cutting and should never be used for grinding as they are thin and don't have the same reinforcement added to withstand the side pressure experienced by disks used for grinding. They can therefore over flex and shatter. Disks should never be used at a rotational speed greater than they were designed for. This means that you shouldn't use a worn down 9 inch disk on for example a 4 1/2 inch grinder.

I only learned this recently but disks have a best before date. Presumably this is due to moisture softening the binding resin and weakening the disk. Disks should be kept in a cool dry place.

If cutting stainless steel, disks made from hard abrasive can be used which won't wear away as quickly. Thinner disks are available for cutting metal sheeting such as roof cladding. Diamond abrasive disks can be used for cutting brick, stone, concrete, slate and roof tiles.

Wire brushes are available for removing rust and paint. These can fling out steel bristles so you need to wear eye protection.

Be alert at all times and watch out for the unexpected and others coming into your workplace. Don't use an angle grinder in the rain because you may end up getting an electric shock. The shock could startle you and the likelihood is that you would drop the grinder and potentially cause injury to yourself.

If possible, don't use the grinder above you because if you lose control, it could drop down on top of you.

Don't use a grinder if you are tired. Tiredness can result in poor concentration and the possibility of an accident and personal injury.

Keep your feet spread apart. This braces your body better and makes it less likely for you to be thrown off balance.

Ensure that the power flex and any extension cords are behind you and can't fall into the path of the cutting disk.

If the workpiece isn't heavy, either weigh it down by standing on it, hold it in a vice or clamp it to a surface. You can usually hold a length of metal down by standing on it with two feet but never use this method with a small piece of metal. I did this once and the grinder disk caught in the metal, fired it up into the air and I didn't find it until a month later on top of a shelf! Keep the material on the waste side of the cut up off the ground so that the disk doesn't have to make contact with the ground and the cut will open up as the material falls away as you cut through.

Hold the machine firmly with two hands, one on the body and trigger, the other hand on the side handle. Remember you are the boss so don't let it overpower you. If the disk gets stuck in the workpiece, the grinder can kickback just like a chainsaw and either pull you into the work or push you backwards depending on whether the disk is traveling towards or away from you at the point of contact of the workpiece. You need to be prepared for this so the grinder isn't thrown out of your hands. If this happens, release the trigger immediately and allow the disk to come to a stop before removing it from the cut.

If you are cutting, you will probably have a guide line drawn on the work piece. Start the grinder, allow the disk to reach max speed (Large grinders may have a slow startup feature to prevent the "kick" on power up) and place the disk gently in contact with the back of the workpiece so that you cut towards yourself. Apply gentle and constant pressure and the metal will start to become red hot. At this stage it becomes soft and cuts easier. Don't overload the machine. Angle the grinder so that sparks are thrown downwards either to one side of your legs or between your legs. Don't allow them to concentrate on one point on your clothes for any length of time or they will cause them to ignite (been there, done that!). A leather apron although cumbersome will protect clothes.

Keep the disk straight and avoid twisting it in the cutting slot to prevent it sticking and causing kickback. Keep your head to one side out of the plane of the disk so that if the disk shatters, hopefully you won't get hit by debris.

When the waste is almost cut away, take care that the disk doesn't get trapped. Release the trigger on the grinder, allow the disk to spin down, watch out that you don't scuff the flex with the disk and only then allow it to rest on the ground. The workpiece and waste will be extremely hot at this stage, so allow them to cool down before moving.

Grind off sharp edges on the work piece and waste (if it is being reused)

Grinding by its very nature may involve using the grinder at all sorts of angles. Try to direct sparks away from you and watch out where they land. Remember all flammable material should have been placed safely out of range. Again watch out for kickback so you need to hold the grinder firmly.