- - AGRICULTURE CORE CURRICULUM - - (CLF2000) Advanced Core Cluster: AGRICULTURAL MECHANICS (CLF2100) Unit Title: TOOL USE AND MAINTENANCE AND SHOP SAFETY ______________________________________________________________________________ (CLF2105) Topic: SHARPENING HAND TOOLS Time Year(s) AND GRINDER SAFETY 2 Hours 1 / 2 / 3 / 4 ______________________________________________________________________________ Topic Objectives: Upon completion of this lesson, the students will be able to: Learning Outcome #: (E-2) - Sharpen selected cutting tools correctly, including chisels, screwdrivers, twist drills, blades, hoes, axes, knives, scissors, and shears. Special Materials and Equipment: Examples of hand and bench grinders, rasps, files, and whetstones should be displayed. Slides, videos, films, and demonstrations concerning safe procedure of hand sharpening tools and grinders will be useful in this lesson. ______________________________________________________________________________ *** NOTE TO INSTRUCTOR *** Demonstrations should be valid and visual in order to demonstrate the true danger in the use of this equipment. Manuals, teacher guides, student workbooks and audiovisual materials concerning shop safety can be acquired from: American Association for Vocational Instructional Materials, 745 Gaines School Road, Athens, GA 30605. Telephone 1-800-228-4689. ______________________________________________________________________________ References: Burke, Stanley R., & Wakeman, T. J. (1990). MODERN AGRICULTURAL MECHANICS (2nd ed.). Danville, IL: Interstate Publishers. Cooper, Elmer L. (1987). AGRICULTURAL MECHANICS: FUNDAMENTALS AND APPLICATIONS. Albany, NY: Delmar Publishers. Evaluation: Quiz administered by the instructor. TOPIC PRESENTATION: SHARPENING HAND TOOLS AND GRINDER SAFETY A. Hand Sharpening Tools Safety 1. Files, rasps, and whetstones are used to sharpen a variety of shop tools. (Much of this information has been presented in previous units, but a review can be of great importance due to the danger of the equipment in use.) 2. Unskilled and/or careless use of files and rasps causes numerous injuries while sharpening tools. a. Never use a file or a rasp without a handle. The pointed end can puncture or lacerate the skin. b. Always use two hands while filing. This prevents the tool from bouncing off the work material and onto the worker. The flat edges of the file or rasp are sharp enough to cut skin. c. Use the file in one direction only. File away from the body to prevent injury. The teeth of the file are generally facing one direction. To file against the teeth will cause the file to bounce off the work material and injure the worker. 3. Whetstones are used to sharpen knives, scissors, and other flat-bladed tools. a. Always keep hands and fingers clear of the area of the stone where the tool is being sharpened. b. Secure the whetstone before sharpening a tool in order to prevent slippage. B. Grinder Safety 1. A grinder is a piece of power equipment used to abrasively remove metal from a larger piece of material. 2. Two types of grinders are commonly found in the shop. a. A bench grinder is larger in size and must be securely mounted to a table or bench. b. A portable hand grinder can be used anywhere that an electrical source is available. 3. There are many specific safety practices regarding grinders. a. All guards and safety devices must be in place and be operable before using. These devices include shields and eye shields. b. The tool rest on the bench grinder must be in proper adjustment at all times. c. Inspect the grinding wheel for grooves, cracks, or chips before operating. d. Always wear personal eye protection when operating a grinder. Never rely on the eye shields on the grinder alone. e. Never wear gloves, neckties, or loose-fitting clothing while operating any power equipment. f. Cool the tip of the material being ground often. This prevents a weakening of the metal and possible breaking of the tool. g. Never stand directly in front of the grinding wheel as it is coming to speed. A loose-fitting or unbalanced wheel may fly from the assembly and cause serious injury. h. Keep the spark deflector in place and never more than 1/8" from the grinding wheel. A space of more than 1/8" allows metal to be pulled between the toolrest and the grinding wheel. This action may catch fingers, cause the metal to be thrown by the grinder, or break the grinding wheel or toolrest. i. Always grind on the face of the grinding wheel and never on the sides. Constant side pressure may cause the wheel to break. j. Always use two hands when using a portable grinder. The high speeds of the wheel can cause the grinder to fly off the metal and injure the worker. __________________________________________________________ ACTIVITY: 1. Set up grinders with safety problems and have students inspect them. 2. Identify all of the safety features on grinders and describe the function of each. 3. Set up graphic demonstrations in order to show the effects of improper safety practices. For example, show the effects of a glove or a piece of loose clothing getting caught in an improperly adjusted tool rest. 4. Have students demonstrate the safe use of hand sharpening tools and grinders while sharpening tools. __________________________________________________________ SAFETY IN TOOL FITTING* Safety Practices for Fitting Tools Tool fitting is defined as the sharpening, cleaning, redressing, and adjustment of tools so they can better do the work they were designed to do. The following general safety precautions should be observed when fitting tools. As these precautions deal with general tool-fitting applications, other more specific safety measures may need to be implemented when performing specialized tool-fitting jobs. 1. Use solvents and chemicals safely. All solvents and cleaning chemicals used in tool fitting should be handled and stored according to the manufacturers' directions. Use solvents and chemicals only in well-ventilated areas. When using many chemicals, you must wear rubber gloves. 2. Fasten or hold tools to be fitted securely. Hold the workpiece firmly when grinding, filing, or performing other reconditioning operation. Do not allow the workpiece to be thrown, dropped, or chipped while it is being fitted. 3. Use handles on files when tool fitting. File handles will prevent the tang from being gouged into the hand. 4. Wear approved eye protection. Industrial-quality eye protection should be worn at all times. 5. Avoid loose-fitting clothing when you are grinding. Do not wear long sleeves and loose-fitting clothing when you are using a grinder because they are cumbersome and could get caught on the grinder. 6. Gloves are recommended only when materials being handled will cause injury to the hands. Gloves are awkward; thus, they produce extra hazard, especially for the worker who is using a grinder. 7. When using the stationary grinder for tool fitting. a) Keep the tool rest no more than 1/8" from the grinding wheel. b) Sound the grinding when it is mounted for cracks and internal flaws. c) When turning on the machine, stand to the side of the grinding wheel. Never stand in direct line with the grinding wheel while it is coming up to operating speed. d) Keep the face of the grinding wheel true. Use a grinding wheel dresser to true the wheel and remove glaze from the wheel surface. e) Keep grinder eye shields in place and clean at all times. f) Keep the spark deflector in place and adjusted so it is never more than 1/8"from the grinding wheel. g) Grind only on the face of the grinding wheel. Heavy side pressure may cause the grinding wheel to break and then strike the operator. h) Replace the grinding wheel when it is worn to within half of its original diameter. The surface grinding speed of the wheel is reduced when the grinding wheel is worn, resulting in a rough grinding surface. It is also difficult on most grinders to keep the toolrest adjusted to within 1/8" of the grinding wheel when the wheel is worn to less than half of its original diameter. If the toolrest cannot be properly adjusted, a safety hazard exists. A space of more than 1/8" allows metal to be pulled between the toolrest and the grinding wheel. This action may catch fingers, cause the metal to be thrown by the grinder, or break the grinding wheel, toolrest, or both. i) Use water to cool the tools being fitted. Frequent cooling prevents loss of temper from the tool and burns to the operator. Tools should be cooled enough to hold in your hand without burning before grinding is resumed. j) Do not grind when other workers are near. A bump to someone grinding may cause serious accident. k) Never leave the grinder running unattended. l) Do not exceed the recommended speed (RPM) of the grinding wheel. m) Never modify a grinding wheel to run on an arbor shaft smaller than the smallest bushing provided with the grinding wheel. _____________________ * Reprinted by permission of Interstate Publishers, Inc., from MODERN AGRICULTURAL MECHANICS, 2nd ed., by Stanley R. Burke and T. J. Wakeman. Copyright 1992 by Interstate Publishers, Inc. 7/10/91 DLF/RRE/tf #%&C