Drills & drill bits Engines: Motive Power Types: Handout Activity: HA012 HA012-2 Student/Intern information: Name Date Class Drills & drill bits Summary Drills can be portable or bench mounted. A bench mounted drill allows accurate drilling with more control - more so than a portable drill, which is convenient but can be difficult to guide accurately. This is a portable drill. It has a cord you have to plug into an electrical supply. The voltages used depends on both the country supply and whether a low voltage isolation transformer is used a a safety measure. Cordless models use their own internal batteries. When you can t bring the work to the drill, you can take the drill to the work. But don t expect it to put large holes through very hard metal, although they are very versatile they are limited to the amount of work they can do by their power rating. The biggest drill bit that ll fit in the chuck of these drills is usually marked on the body of the drill or chuck, along with the speeds at which it turns. Many portable drills have two operating speeds but some portable drills have a variable speed rating that is determined by how much pressure is placed on the trigger and can be set to any speed within their range. 20070813 Page 1
Drills & drill bits HA012-2 Drill bits come in many closely spaced sizes. The most common is the twist drill. It has a point, and a body, usually with two spiral grooves, and its shank is gripped in the jaws of the drill chuck. There are different types for the materials to be drilled. A bench mounted drill allows accurate drilling with more control - more so than a portable drill, which although convenient, can be difficult to guide accurately. A mounted drill can feed the drill bit at a controlled rate, and the work table on the drill normally has a vice to secure the job at a constant angle to the drill bit. Also, this drill can be set to run at different drilling speeds. This drill chuck takes bits up to 13 millimeters or one half inch in diameter. A Morse taper is a system for securing drills. The morse taper size changes according to drill size. The shank of the drill bit is tapered and looks like the tang of a file. It fits snugly into the drill spindle which has a similar taper on it s inside. The tang on the drill bit is located in the spindle and it drives the drill. It s a quick way to change drills without constantly adjusting the chuck. When there s already a hole drilled in sheet metal that needs enlarging, a multi-fluted tapered hole drill will do the job in about the same time it takes to say it. A drilling speed chart should be kept near the bench or pedestal drill. It compares drill sizes and metals to show the proper speed. So, to drill a 10 millimeter or 2/5 of an inch hole through this piece of aluminum, the drill speed should be 1,800 revolutions per minute. 20070813 Page 2
Drills & drill bits HA012-2 1. Many portable drills have two operating speeds but some portable drills have a variable speed rating that is determined by how much is placed on the trigger and can be set to any speed within their range. 2. A mounted drill can feed the drill bit at a controlled rate, and the work table on the drill normally has a to secure the job at a constant angle to the drill bit. 3. Cordless models use their own internal. 4. The tang on the drill bit is located in the spindle and it drives the drill. It s a quick way to change drills without constantly adjusting the. 5. The of the drill bit is tapered and looks like the tang of a file. It fits snugly into the drill spindle which has a similar taper on it s inside. Score / 5 Supervisor/Instructor information: Name Signature Date 20070813 Page 3
Power grinder Engines: Motive Power Types: Handout Activity: HA013 HA013-2 Student/Intern information: Name Date Class Power grinder Summary Power grinders come in different sizes and speed ranges. The size of a power grinder is the diameter of the largest wheel or disc it takes. Power grinders come in different sizes and speed ranges. The size of a power grinder is normally determined by the diameter of the largest grinding wheel or disc that can be fitted to it. Grinding wheels and discs usually have a maximum safe operating speed printed on them. This maximum speed must never be exceeded or the wheel or disc could disintegrate. Every well-equipped workshop has a solidly mounted grinder, either on a pedestal bolted to the workshop floor, or securely attached to the workbench. Appropriate eye protection must be worn when grinders are being used, and the wheel guards must be correctly and firmly in place. A bench grinder or pedestal grinder normally has a rating with the size of the grinding wheel it can take. Bench or pedestal mounted grinders take grinding wheels in grades from coarse to very fine, depending on the size of the abrasive grains that are bonded together to make the wheel. They also range in hardness, depending on the abrasive used and the material that bonds the particles together. If a particular grinding application is required, a check should be done to find out the most suitable grinding wheel for it. A straight grinder or more commonly, an angle grinder is needed when the bench grinder is not appropriate. The straight grinder takes conventional grinding wheels, just like the stationery grinders, although they re limited to a grinding wheel diameter of about 125 millimeters or 4 3 4 inches. 20070813 Page 1
Power grinder HA013-2 The angle grinder uses discs, rather than wheels. During grinding, the face of the disc is used instead of the edge. There are special discs that can fitted to these machines that can be used for cutting. They use the edge of the wheel and are useful for jobs that can t be reached with a hacksaw. 1. A straight grinder or more commonly, an grinder is needed when the bench grinder is not appropriate. 2. The size of a power grinder is normally determined by the of the largest grinding wheel or disc that can be fitted to it. 3. There are special discs that can fitted to these machines that can be used for. 4. Every well-equipped workshop has a solidly mounted grinder, either on a bolted to the workshop floor, or securely attached to the workbench. 5. A bench grinder or pedestal grinder normally has a with the size of the grinding wheel it can take. Score / 5 Supervisor/Instructor information: Name Signature Date 20070813 Page 2
Air tools HA974-2 Handout Activity: HA974 Student/Intern information: Name Date Class Air tools Summary Air tools use compressed air to do a number of tasks. They can include the air impact wrench, air ratchet, air chisel, air drill & air duster. Air can come out of a pneumatic tool with a lot of force, and that can cause damage and injury so it s important to be careful when using and air tool. Air tools use compressed air to do a number of tasks. Air can come out of a pneumatic tool with a lot of force, and that can cause damage and injury. So before using an air tool, it s important to check all of its connections are secure, and the hoses are in good condition and not leaking. It must be lubricated before it s used. This may be done automatically by an in-line oil mister that puts a mist of oil in the air supply. Or it may need some squirts of light oil into the air inlet fitting. This model also removes moisture from the air before it s fed to the tools. The most common pneumatic tool in an automotive workshop is the air impact wrench. It s sometimes called a rattle gun. It s easy to hear why. Taking the wheels off a car to replace the tires is a typical application for this air tool. It often needs a lot of torque to twist the nuts free. The rattle gun can be set to spin in either direction, and this valve controls how much torque it applies. It should never be used for finely tightening wheel nuts. There s a real danger of doing them up much too tight. That could cause the bolts to fail and the wheel to shear off the vehicle while it s moving. Another rule with the air impact wrench is to use only these specially hardened impact sockets, extensions and joints. The sockets are special 6-point types, and these flats can stand the sudden force that the rattle gun provides. 20070926 Page 1
Air tools HA974-2 This is an air ratchet. It uses the force of compressed air to turn a ratchet drive. It s used on smaller nuts and bolts. Once the nut is loosened, the air ratchet spins it off in a fraction of the time it would take by hand. This is an air chisel. It s useful for driving and cutting. The extra force that s generated by the compressed air makes it more efficient than a hand chisel and hammer. Just as there are many chisels, there are many bits that fit into the air chisel, depending on the job at hand. This is an air drill. It has some important advantages over the more common electric power drill. With the right attachment, it can drill holes, grind, polish, and clean parts. Unlike the electric drill, it doesn t run the risk of producing sparks. Which is important around flammable liquids or gasoline tanks. An air drill doesn t trail a live electric cable behind it which could be cut, and cause shock and burns. And an air drill also doesn t get hot with heavy use. This is the simplest air tool. It s a blowgun or air duster. It s really just compressed air by itself, controlled by a lever, or valve. It s used to blast debris and dirt out of confined spaces. That can be dangerous, so eye-protection must be worn whenever it is used. Noise levels are usually high, so ear protection should also be worn. It s also dangerous to use it to clean yourself down. Its blast should always be directed away from the user and anyone else working nearby. 20070926 Page 2
Air tools HA974-2 1. Unlike the electric drill, an air drill doesn t run the risk of producing. 2. When using a blowgun or air duster, levels are usually high, so ear protection should also be worn. 3. An air tool must be before it s used. Score / 3 Supervisor/Instructor information: Name Signature Date 20070926 Page