36 Mechanical Workshop Practice 3. Steel metal works 4. Carpentry 5. Smithy 6, Foundry 2. Machining processes: Using metal-cutting machine tools, the machining operations are executed to shape parts. The loading of the workpiece, control of the machining operations, the unloading and inspection are done manually. The conventional ‘machining operations practised are as follows: 1. Turning 2. Drilling 3. Shaping 4. Slotting 5. Milling 6. Grinding The theory and practice of various hand-working processes as well as machining processes are explained in the Modules B and C respectively. 2.2 Safety Measures Safety is the primary requirement that a worker or student should learn before he starts ‘working in a workshop. A worker or student can easily learn how to work safely. Rules ‘and regulations, mechanical guards and devices, posters and lectures about safety measures ate very important, but they will never replace intelligent precautions taken by the worker or student in doing his work. A good and safe worker is the one, who is safety-conscious and always adopts safe and accepted procedures. The following ate the types of safety measures to be considered in a workshop. 1, Safety of the worker 2. Safety of the job 3, Safety of machines, tools and equipment ‘To maintain safe working conditions and to avoid accidents, different types of safety measures are taken, depending upon the type and seriousness of accident that may happen. A student, who is going to practice in workshops, has to know the following important safety measures. Wear safe clothing ‘Wear tight shirt or dress while working inside the workshop. For good protection of the clothing, shop apron may be worn, Wear shoes with thick soles. Do not wear rings, ‘watches, bracelets, or other jewellery that could get caught in moving machine,Workshop Practice and Record Writing 37 Maintain good housekeeping habit Keep the workshop floor free of oil, grease or any other liquid, Store materials in such away that they cannot cause hazards, Do not leave tools or workpieces on the work bench or table of machine. They should be kept in the places allotted for them. Clean the work bench or machine after a work and place the scrap in the scrap box. Follow the general safety measures While working with machines, the guards should be in position. Replace them immediately after repairs, if any. Do not try to clean or repair a machine, if itis im motion, Cutting tools and workpiece on any machine should be clamped securely before starting. An operator of a machine should not lean against a machine, He should avoid unnecessary talking, while operating the machine, Sufficient light should be provided at the working area, Take precaution while using hand tools 1. Hammers: Do not use a hammer, unless the head is tightly fixed to the handle. Place the hammer on the bench carefully in the proper position. A falling hammer can cause serious foot injuries. Never strike two hammers together, because the faces of hammers are very hard and blow may cause a chip 10 break off, while hammering 2. Chisels: While hammering on a chisel, care should be taken to get the blow correctly on the striking head (back) of the chisel, otherwise, it may eause injury to the chisel holding hand. Mushroomed striking head of the chisel should be removed by grinding. The cut edges are often sharp and may cause injury to hand. They may be removed by filing or grinding, 3. Files: Never use files without proper handles. The surface of the file should be clean and dirt-free, Never hammer on a file or use the file for hammering, because files are made of very brittle material 4. Saw: Do not test the sharpness of the blade of a saw by running a finger across the teeth, While using a saw, check whether there is proper tension of the blade. Do not apply heavy pressure or sideways force on the saw, because it may break the blade and even cause injury to hand. Take precaution while operating machine tools 1. Drilling machine: Fix the drill bit tightly on the chuck and remove the tightening key. Clamp the workpiece on the machine vice before starting drilling. The drilling surface should be perpendicular to the axis of rotation of the bit. A punch mark at the position of drilling can give accuracy in hole location. While drilling of small diameters, (Jess than 5 mm) the axial load should be low in order to protect the bit from breaking. Clean the chips from the machine table using a brush, 2. Lathe: Before starting the machine, clamp the work on the chuck solidly. Turn the chuck or face plate by hand to inspect the working, prior to the starting of machine38 Mechanical Workshop Practice Keep the machine clear of tools and then start, Do not stop the rotation of chuck by hand. Take measurements only after stopping the machine. Do not remove chips by hand; use brush or plicrs if necessary, to remove long chips. While working on the lathe, only the operator has to switch on/off the machine, and not by a second person, 3. Grinding machine: Wear goggles or a face shicld while grinding on a grinding nachine, The wheel-guard and tool-rest should be fitted on the machine properly While grinding, do not press the work or tool too much on the wheel and it should be held firmly by hand. Never operate a grinding wheel at speeds higher than that recommended by the manufactute. 2.3 Preparing for the Workshop Practice ‘An engineering student who is going to do workshop practice, has to prepare the following prior practice: 1, The student has to posses the following: materials (a) Work record of A4 size (b) Fair record approved by the workshop authorities. (©) Pen, clutch pencil, eraser and a straight edge. 2. Students are advised to wear tight dress, preferably pants and shirts. Girl, students have to tie their hair and tuck neatly as a precaution against being caught against moving machine pars. For good protection of clothing, a shop apron of dark colour may also be worn, Wearing of shoes instead of slippers is also recommended for the safety of legs from sharp and hot chips and material other waste 3. Study the relevant theory about the process, tools, equipment and the material being used for the practice. Usually the students are given a study of the workshop tools and equipment prior to the practice. 2.4 Writing of the Work Record ‘A work record is the write-up and sketches prepared by the student along with the study of tools and equipment or workshop practice. 2.4.1 Writing of Work Record for a Study Before starting the actual practice in a workshop, the instructor gives description about the different types of tools and equipment used for cutting, holding, measuring, ete ‘Students are allowed to handle the tools and thus to become familiar with the shape, ‘name of parts, and the method of using them. After the study, the students are required