Holding Devices Lecture Module PDF

1 LEARNING GUIDE Week No.: __6__ TOPIC: HOLDING D...

1 LEARNING GUIDE Week No.: __6__ TOPIC: HOLDING DEVICES I. EXPECTED COMPETENCIES Upon completing this Learning Module, the student will be able to: a. to understand the importance of Holding devices used in Bench Work b. to identify the different types of vise commonly used in Bench Work c. to be able to know the Do’s and Don’ts when working with Holding Devices II. CONTENT/TECHNICAL INFORMATION Bench work has its own essential position in all engineering works. In the mechanized workshops, where most of the work is carried out on an automatic machine, while bench work has its own importance. The jobs can be finished to a fairly good degree of accuracy through machining operations to be done on them to finished to the desired accuracy. A fitter’s work is unavoidable when different parts are to be assembled in position after they have been finished. Alignment of machine parts, bearing, engine, slide valves and similar other works call for a fitter’s work. Reconditioning and refitting of machines and machine parts cannot be done without a skilled fitter. All the above types of works require the use of a large number of hand tools and a fitter must have good working knowledge of all these tool and instruments. Holding tools are also known as Work Holding devices in the Bench Work. They are used to hold all types of components between jaws (Fixed Jaw and Movable Jaw). Most vises can be used for a wide variety of work. Select the most suitable vise which is strong enough for the work.  Wear safety glasses or goggles, or a face shield (with safety glasses or goggles) when using striking tools or power tools on a workpiece held by a vise.  Attach a vise securely. Place bolts in all the holes in the base of the vise. Use lock washers under the nuts.  Mount a vise so that the stationary jaw projects slightly beyond the edge of the workbench. This allows long work to be clamped in the vise without interference from the edge of the workbench.  Ensure that the workbench is firmly secured to its base. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  2  Check the vise for cracks or other damage before clamping a workpiece in it.  Use a vise large enough to hold the work without strain.  Place the workpiece in the vise so that the full clamping surface of the jaw supports the workpiece  Keep the workpiece in the vise close as possible to the jaws to prevent vibration when sawing, filing, etc.  Support the end of extra-long work with an adjustable stand, saw horse, or box rather than putting extra strain on the vise.  Keep all threaded and moving parts clean, oiled and free of chips and dirt.  Use jaw liners in a vise where there is any possibility of marking the work.  Replace a bent handle and worn jaw inserts. What should I not do?  Do not weld the base of the vise to any metal.  Do not repair a vise by welding or brazing.  Do not try to bend a heavy rod in a light vise.  Do not cut into the jaws.  Do not apply heavy pressure at the corner of the vise jaws.  Do not use a handle extension (e.g., a pipe) for extra clamping pressure.  Do not hammer on the handle to tighten beyond hand pressure.  Do not use the jaws of the vise as an anvil.  Do not use any vise that has the slightest crack.  Do not unscrew or open the jaws of the vise wider than they were designed to be used. The Various Work holding devices are  Workbench  Bench Vise  Pipe Vise  Hand Vise  Toolmakers Vise This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  3 Work Bench:  It is used to hold various components on its surface.  It also gives support to a human while performing various operations. Bench Vise: It is firmly fixed to the bench with the help of nuts and bolts. It consists of a cast Iron body and cast iron jaws. Two jaw plates are fitted on both the jaws. The holding surface of the jaw plates is knurled in order to increase the gipping. Jaw plates are made up of carbon steel and are wear resistant. One jaw is fixed to the body and the second slides on a square threaded screw with the help of a handle. The jaws are opened up to required length; job is placed in the two jaws and is fully tightened with the help of handle. Handle is used to move the movable jaw  Bench Vise is a holding tool which is used to hold the specimen or the workpiece between the two jaws. The Parts of Bench Vise are: 1. Jaws o Fixed Jaw o Movable Jaw 2. Body 3. Handle Parts of Bench Vise Jaws: The Jaws are used to hold the workpiece by rotating the handle. In that, one jaw is fixed and the other is movable. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  4 Rankin Kennedy C.E, Fitter’s metalworking bench vise A “Parkinson’s Perfect” brand, with quick- release screw Scans from ‘The Book of the Motor Car’, Rankin Kennedy C.E., 1912 Body: All the parts like a handle, jaws etc.are connected to the body of a bench vise. Handle: If the handle is rotated in CW direction, then the work-piece is fixed between two jaws. If the handle is rotated in CCW direction, then the workpiece is loosened from the jaws. Pipe Vise:  It is similar to Bench Vise but here the Circular/Cylindrical components are to be placed in between the upper and lower jaws due to the curvature of existing jaws.  The Parts of pipe vise are handle, screw spindle, movable and fixed jaws, etc. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  5 Hand vise:  A hand vise is a tool that is designed to hold the workpieces in between the jaws.  The wingnut is tightened in CW direction to hold the w/p and loosened in CCW direction. Tool maker’s vise:  The screw-driven movable jaw for applying clamping force.  Made from hardened alloy steel.  Single piece construction with V-grooved Jaws.  All surface including Jaws and Base are precision ground square and  parallel. https://www.pinterest.ph/FredaLaRue1/toolmaker/ This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  6 PROGRESS CHECK Multiple Choice 1. Vises should always be secured to the workbench with screws A. True B. False 2. The ----------- is used to hold the material firmly during cutting and shaping operations. a) Bending machine b) Clamping machine c) Notching machine d) Bench-vise e) None of the above 4. 1 inch diameter Copper tubes are best hold on a tool makers vise. A. True B. False 5. Work benches are usually 1 meter in height. A. True B. False 6. Work bench should be firmly secured on the floor if possible be bolted. A. True B. False 7. It is considered the third hand of a worker. A. Pliers B. Locking Pliers C. Machinist vise D. Shears 8. If you notice stress fractures on the bench vise try to weld it your self immediately for repairs. A. True B. False 9. A vise use to hold small objects tight while grinding, drilling, filing, hammering, sanding, shaping, etc. Jaws have vertical and horizontal V grooves for holding round objects. A. Tool maker’s vise B. Pipe vise C. Bench vise D. Hand Vise 10. When tightening your work on a bench vise especially pipes, to increase handle leverage use a pipe as an extension. A. True B. False REFERENCES Occupational Safety and Health Administration (2020). Evacuation Plans and Procedures eTool: Emergency Standards to Portable Fire Extinguishers. https://www.osha.gov/SLTC/etools/evacuation/portable.html Dixon,R. (1981). BenchWork: Delmar Laknepally, V., Narsampet, M. (2020). Engineering Workshop Laboratory Manual This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  7 Department Of Mechanical Engineering. Retrieved From: Engineering-Workshop-i-Lab- Manual_1st%20year.pdf LEARNING GUIDE Week No.: __7_ TOPIC: CHISELING I. EXPECTED COMPETENCIES Upon completing this Learning Module, the student will be able to: a) to understand the importance of chiseling and how does it works b) to explain the basic principles of how cold chisel are made, how to take care of them and usage safety. c) to identify the different classifications of cold chisel II. CONTENT/TECHNICAL INFORMATION Chiseling is a term applied to benchwork that describes metal cutting process by a wedge shaped cutting tool called a cold chisel. How it works: Cutting process can be accomplished in any of the three methods namely; parting or dividing, chipping, and shearing. Parting or Dividing: Parting operation is the process of allowing the cutting edge of the cold chisel to penetrate into the workpiece by driving the head vertically with several blows of the hammer. The force applied on the head of the cold chisel causes the material to yield at the point of penetration and giving way to the cutting edge until parting is accomplished. The utilization of the applied force depends on the size of the lip angle. Lip Angle Small Normal Large Force \ Required least medium high Ease of Penetration easy moderate hard Risk of Breakage large less least Application soft medium hard metal metal metal This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  8 Chipping: It is the process of removing considerable amount of the metal on the workpiece by driving the cold chisel in an inclined position and allowing it to move parallel to the surface. The workpiece should be clamped rigidly in the vise to counteract the forces applied on the head. Shearing: Shearing is the process of cutting a piece of steel place across its thickness in the vise. Shearing action is done when the width of the cutting edge cuts the full thickness of the workpiece diagonally. The cutting edge and the opposite jaw facing the worker serves as guide to cut in straight line. The Cold Chisel: The cold chisel is a wedge-shaped cutting tool used in cutting metal. It is provided with a shank for gripping, the head for driving with a hammer and the cutting edge for cutting. Types of Cold Chisel: 1. Straight Cutting Edge is used for trimming, edge chamfering, shearing, chipping and dividing. 2. Round Cutting Edge is used for dividing and cutting irregular shape. 3. Cape Chisel is used for grooving and keyway cutting. MATERIALS USED IN MAKING COLD CHISEL: Cold chisel should possess toughness to resist impact and hardness to cut other metals. Considering these physical properties, a high carbon steel with 0.6 to 1 percent carbon and some percentage of manganese, silicon, chromium and vanadium is a good material for cold chisel. Steps in the manufacture of cold chisel: 1. Blanking- cutting to length. 2. Forging- heating to forging temperature (2000 to 2500°F) and forming the cutting edge. 3. Stress Relieving- after forming it is heated again to about 1425°F to remove stresses developed during forging. 4. Hardening- heating the workpiece above it critical temperature and quenching it in oil or water (heating temperature 1675°F) 5. Tempering- reheating to remove brittleness and sacrificing a bit of hardness (tempering temperature 350 to 950°F) 6. Sharpening- grinding to proper lip angle. Care and Maintenance: Cold chisel should not be used to cut hardened materials or against hardened surfaces. Blunt cutting edges does not give efficient performance but rather damage the workpiece and becomes a hazard to other worker because of the tendency to fly- off it too much force is applied. As much as possible cutting edge should be sharpened to proper lip angle. Keep it free from rust and preventing the head from development of burrs or mushrooms. This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  9 Safety: 1. Burrs or mushrooms should be removed by grinding. 2. The hammer being used to drive the cold chisel must have a firmly seated handle. 3. In hammering, the hammer must hit the head of the cold chisel along its axis. 4. Place guard or protective covering around your work to prevent chips from flying. PARTS OF CHISEL This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.  10 III. PROGRESS CHECK Multiple Choice 1. Metal cutting -----------are used with steel-headed hammers for chipping or cutting material A) Hacksaw B) Chisels C) Punch D) File 2. Chisels made for general metal work are known as _____ chisels. A. Flat B. Cold C. Hot D. Ground 3. Which chisel shape is used when removing damaged rivets? A. Diamond B. Round nose C. Flat D. Cape 4. Which chisel shape is used when creating sharp corners? A. Diamond B. Round nose C. Flat D. Cape 5. Which chisel shape is used when cutting keyways? A. Diamond B. Round nose C. Flat D. Cape 6. Which chisel shape is used when cutting concave grooves? A. Diamond B. Round nose C. Flat D. Cape1. 7. What determines the size of a chisel? A. pitch B. width C. weight D. length E. height 8. In chiseling the utilization of the applied force depends on the size of the ________. A) Lip angle B) Head C) Ferrule D) none of these 9. Straight Cutting Edge chisel is used for except A)grooving B)trimming C)shearing D) chipping 10. In manufacturing of chisel, ______ is heating to temperature of (2000 to 2500°F) and forming the cutting edge. A) Hardening B) Forging C) Tempering D) Quenching IV. REFERENCES Canadian Center for Occupational Health and Safety(2020). Hand Tools -Wrenches https://www.ccohs.ca/oshanswers/safety_haz/hand_tools Dixon,R. (1981). BenchWork: Delmar Laknepally, V., Narsampet, M. (2020). Engineering Workshop Laboratory Manual Department Of Mechanical Engineering. Retrieved From: Engineering-Workshop-i-Lab- Manual_1st%20year.pdf This module is a property of Technological University of the Philippines Visayas and intended for EDUCATIONAL PURPOSES ONLY and is NOT FOR SALE NOR FOR REPRODUCTION.