Workshop Theory And Practice: Hand Tools And Bench Work PDF

COE0035L WORKSHOP THEORY AND PRACTICE Introduction to machine shop operations, layouts, tools and measuring instruments “Hand Tools and Bench Work”  CHAPTER 1 OBJECTIVES At the end of the chapter, the learner should be able to: – Identify the differ...

COE0035L WORKSHOP THEORY AND PRACTICE Introduction to machine shop operations, layouts, tools and measuring instruments “Hand Tools and Bench Work”  CHAPTER 1 OBJECTIVES At the end of the chapter, the learner should be able to: – Identify the different hand tools; – Understand the bench working techniques; and – Learn bench working techniques and how to use the different hand tools.  Hand Tools a tool held in the hand and operated without electricity or other power. Bench Work work done at a workbench, worktable, etc., as in a factory or laboratory. WORK HOLDING TOOLS/ DEVICES BENCH VISE A Bench vise, usually swivel based is the kind most favored for general work. It is securely fastened to the bench with bolts. The faces of the jaws are usually lightly serrated and hardened to ensure a firm grip on the work. V - BLOCKS Are used to hold circular work when laying out or setting up for machining. Some V- blocks are fitted with a clamp to work securely in position.  TOOLMAKERS’ HANDVISE Is a small steel vise with two interchangeable blocks. The choice of block to be used depends on the size of the article to be held by the vise. It is used by toolmakers at the bench for small machining operations such as drilling or tapping. C- CLAMP It is an all purpose clamp, made in the shape of the letter C. In general, it is use to hold work pieces on machines such as drill presses, as well as to clamp parts together. The size of the clamp is determined by the largest opening of its jaws  TOOLMAKERS’ PARALLEL CLAMP Is consist of two flat steel jaws which may be adjusted to fit a piece of work by means of a screw passing through the center of each jaw. Another screw in the end of one jaw is used to exert pressure on the other jaw. This pressure lightens the opposite ends of the jaws. It is used by the toolmakers for holding small parts both at the bench and at machines. VISE GRIP A latching mechanism that have an exceptionally high degree of mechanical advantage. This means that they are exceptionally strong when locked down. WORK CUTTING TOOLS/ DEVICES SAW is a tool consisting of a tough blade, wire, or chain with a hard toothed edge. It is used to cut through material, very often wood. The cut is made by placing the toothed edge against the material and moving it forcefully forth and less forcefully back or continuously forward.  HAND SAW -are used to cut pieces of wood into different shapes. ❑Crosscut saw - is designed for cutting wood perpendicular to (across) the wood grain. ❑Rip saw - is a wood saw that is specially designed for making a rip cut, a cut made parallel to the direction of the wood grain. Crossed Cut Saw Rip Saw  Common tooth pattern found on cross cut saw COPING SAW is a type of hand saw used to cut intricate external shapes and interior cut-outs in woodworking or carpentry. It is widely used to cut moldings to create coped rather than miter joints.  HACKSAW This type of hand tools features a fine- toothed blade tensioned in a C-frame. Commonly used for cutting metals and plastics. TIN SNIP are a common cutting tool used for cutting thin sheets of metal, plastic, fiber and so forth. They are used not only by tinsmiths, but by all bench workers as a utility tool. They are made in many sizes. WORK STRIKING TOOLS/ DEVICES HAMMER is a tool or device that delivers a blow (a sudden impact) to an object. Most hammers are hand tools used to drive nails, fit parts, forge metal, and break apart objects. Hammers vary in shape, size, and structure, depending on their purposes.  Ball-peen Hammer – it has a flat face which is use for general work while the round end is used for peening and riveting. Straight peen Hammer – it has a peen that is parallel to the axis of the handle. It is used for stretching and drawing out metal when forging. Cross peen Hammer – it has a peen that is at right angle with the handle. It is used for stretching and drawing out metal when forging. Claw Hammer - a hammer with one side of the head split and curved, used for extracting nails MALLET is a kind of hammer, often made of rubber or sometimes wood, that is smaller than a maul or beetle, and usually has a relatively large head. CHISEL Is a tool made from hexagon or octagon shaped tool steel, commonly called chisel steel, of a size convenient for handling. One end is shape for the cutting operation. The other end is left blunt to receive the blows from a hammer. Chisels are usually forged to the required shape, then annealed, hardened and tempered. Finally, a cutting edge is ground. TYPES OF CHISEL 1. Flat cold chisel 2. Cape chisel 3. Round Nose chisel 4. Diamond Point chisel WORK FILE TOOLS/ DEVICES FILE It is a hand-cutting tool with many teeth, used to remove burrs, sharp edges and surplus metal, and produces finished surfaces. Files are made up of high-carbon steel, hardened and tempered and are used in machine shop work when it is impractical to use machine tools. Main Parts of a Hand File Tang Length Tip Edge Heel Face Two Classes of Files Single-Cut Files Double-Cut Files Single-Cut Files This file has a single row of parallel teeth across the face at an angle from 65 to 85. These are used when a smooth surface is desired, and when harder metals are to be finished. Double-Cut Files These files have two rows of teeth crossing each other, one row being finer than the other. The rows crossing each other produce hundreds of sharp cutting teeth, which remove metal quickly and make for easy clearing of ships. Degree of Coarseness Both single and double cut files are manufactured in various degrees of coarseness. On larger files this is indicated by the terms rough, coarse, bastard, second-cut, smooth, and dead smooth. On smaller files, the degree of coarseness is indicated by numbers from 00 to 8, number 00 being the coarsest. Shapes of Files Files can be identified through their cross-section, shape and special use. The types of files most commonly used in machine shop are the mill, flat, hand, pillar, square, round, three-square (triangular), half-round, crocket, crossing, warding , barrette and knife. Care of Files Proper care, selection, and use of files are important factors if good results are to be obtained during the filing operation. In order to preserve the life of a file, the following points should be observed: 1. Always use a file with a handle 2. Do not knock a file on a vise or hard-metallic surface to clean it 3. Keep a firm grip on the file at all times 4. Never use a file as a pry or hammer 5. Always store files where they will not rub against other files. Hang or store them separately to preserve their sharp cutting edges Filling Techniques Depending on the task to be accomplished, different files and techniques are used. Stroke length, stroke direction, and pressure can all be modified.  Cross Filing – is used when metal is to be removed rapidly or the surface made flat before finishing by draw filing Rough filing – use a double-cut file and cross the stroke at regular intervals to keep the surface flat and straight. Finishing – use a single-cut file and take shorter strokes to keep the file flat on the work surface.  Draw Filing Is the operation of pushing and pulling a file sidewise across the work. For this purpose, the file should be held firmly in both hands so that only a few inches of the file in the center are actually used. The main objective in draw filing is to obtain a perfectly smooth, level surface. How To care Hand Tools Cleaning Always clean your tools immediately after use. Tools can be washed using a hosepipe and/or scrubbed with a wire brush. Make sure that there is no risk of spreading pathogens while you are washing your tools. Spray light oil on areas prone to rust. How To care Hand Tools Storage Store tools in a dry, sheltered environment. Place tools in racks for easy location and safety. Place similar tools together so that people can see easily what is available. How To care Hand Tools Maintenance Keep metal blades sharp and well-oiled. Check any nuts, bolts, rivets, screws, blades, and springs regularly for wear or damage, and replace if necessary. Sand wooden parts back regularly and oil with a 50/50 linseed oil and turps mix. Label damaged tools, place them out of the way and tell your supervisor or maintenance person.  COE0035L WORKSHOP THEORY AND PRACTICE Introduction to machine shop operations, layouts, tools and measuring instruments “Lay-out Tools”  CHAPTER 1 OBJECTIVES At the end of the chapter, the learner should be able to: – Identify the different lay-out tools; – Understand the lay-out tools working techniques; and – Learn lay-out tools working techniques and how to use the different lay-out tools. Lay-out Is the process of placing reference marks on the blank work piece, or the transfer of measurements from a drawing to the work piece to be machined, filed or cut. Lay-out This means accurately inscribing clean, sharp lines on the blank work piece to show center lines, shape or form of the finished work piece, locations of centers for holes, circle for hole sizes, angles, arcs or curves and slots. Lay-out It is the first operation in work fabrication or in a sequential production works.  TYPES OF LAYOUT SEMI-PRECISION LAYOUT Is usually done by a scale measurement to a tolerance of + 0.4 mm. This type of layout may be a simple pencil or chalk mark. PRECISION LAYOUT It is done with tools that discriminate to a tolerance of + 0.03 mm or finer if possible. It can be complex and involved operations making use of sophisticated tools. Lay out Tools SCRIBERS A sharp, pointed steel tool used to scribe lines on metal being laid out. CENTER PUNCH A marking punch usually made of a hardened steel, both ends of 90 degrees used to mark the work piece prior to such machining operations such as drilling DIVIDER Is a tool with a hardened steel points used for measuring the distance between points, for transferring a measurement directly from a rule, and for scribing circles and arcs on metal. It consists of steel legs that are fixed together or screwed to maintain the position in which it is set. ODDLEG CALIPER (Hermaphrodite calipers, or Oddleg jennys) are generally used to scribe a line a set distance from the edge of a workpiece. The bent leg is used to run along the workpiece edge while the scriber makes its mark at a predetermined distance, this ensures a line parallel to the edge. TRAMMEL Also known as Beam compass, It is a type of divider preferred for scribing large circles. It consists of a bar and two legs. At the end of each leg is a steel point. SURFACE PLATE This have a true, smooth, plane surface from which accurate measurements may be made. It is made of either cast iron or granite. This are used for laying out and inspecting work piece. SURFACE GAUGE A tool which consist of a steel base with a rotating clamp, which holds a steel spindle. On the spindle is clamed a scriber. -This are usually used for scribing lines on layout work and for checking parallel lines. STEEL RULE Although called a measuring tool, may also be considered a layout tool as it is indispensable in layout work for taking measurements not requiring precision  MACHINIST SQUARES Is the metal workers’ equivalent of a try square. It consist s of a steel blade inserted and either welded or pinned into a heavier body at an angle of 90degree. These are used for checking the square ness and perpendicularity of work.  STEEL PROTRACTOR Is a tool used for setting bevels, transferring or checking angles and similar work. It consists of blade and plate. The blade has double graduations from 0 to 180 degrees in opposite directions, thus permitting reading an angle directly and also the used of complementary angles. The blade can be locked firmly at any angle. VEE BLOCKS Are used to hold circular work when laying out or setting up for machining. They are manufactured in pairs from cast iron or steel. Some Vee blocks are fitted with a clamp to work securely in position  Combination Square Set is used for a number of layout operations. The set consists of a blade(graduated rule), square head, protractor, and center head.  The blade is designed to allow the different heads to slide along the blade and be clamped at any desired location. The groove in the blade is concave to eliminate dirt build up and permit a free and easy slide for the heads. By removing all the heads, the blade may be used alone as a rule. The square head is designed with a 45° and 90° edge, which makes it possible to be used as a try square and miter square. By extending the blade below the square, it can be used as a depth rule. The square head can also be used as a level. The protractor head is equipped with a revolving turret graduated in degrees from 0 to 180 or to 90 in either direction. It is used to measure or lay out angles to an accuracy of 1°. The center head, when inserted on the blade, is used to locate and lay out the center of cylindrical workplaces.  COE0035L WORKSHOP THEORY AND PRACTICE Introduction to machine shop operations, layouts, tools and measuring instruments “Measuring Instruments”  CHAPTER 1 OBJECTIVES At the end of the chapter, the learner should be able to: – Identify the different measuring tools; – Understand the measuring tools working techniques; and – Learn measuring tools working techniques and how to use the different measuring tools. Introduction: Measurement - Is an act or process of determining dimension, capacity or an amount of something.  A wide range of measuring tools and devices has been designed, which make it possible for the skilled craftsman to measure and layout work piece to extremely high accuracy.  Machinist and toolmakers use many tools for measuring and laying out work, some are quite simple and inexpensive, and others are more intricate and expensive. Most are used for linear or straight line measurement.  Ruler (rule or line gauge)  A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing, engineering and building to measure distances or to rule straight lines. The ruler is a straightedge which may also contain calibrated lines to measure distances. Different Types of Rule STEEL RULE -The standard steel rule is graduated in inches and fraction of an inch for the English System and in Centimeters and Millimeters for the Metric System. Then for your convenience in reading the rule, the fractional divisions are indicated by the division mark of different lengths STEEL RULE NARROW RULE A narrow rule is made of tempered steel about 3/64 inch thick, 3/16 inch wide and 4 to 12 inch long. It has graduation combinations number 10 or 11 and is useful for measuring in small openings and spaces. NARROW RULE HOOK RULE It has a hook attached to one end, which makes it easy to take measurement from an inside edge when it is not convenient to see the end of the rule. A narrow hook rule is made for measuring in holes as 3/8 inch in diameter. It is also used for measuring outside dimensions. HOOK RULE FLEXIBLE STEEL RULE This is made of tempered spring steel about 1/64 inch wide and 6 inches long. It is available in many graduation and lengths. This type of rule is for general use and for measuring curved work FLEXIBLE STEEL RULE SHORT LENGTH RULE HOLDER This type of rule is useful in taking measurement in small openings where the ordinary rule can’t be used. The blades are tempered steel and comes of in lengths of ¼, ½, 3/8, and 1 inch. To change the blades, the knurled cap is loosened and then a different blade is inserted in the split chucking pin at the end of holder SHORT LENGTH RULE HOLDER TAPE RULE It is a metallic tape usually 72 inches long that is used to measure bar stock and other long materials. When not in used, the tape may be retracted or ruled back into its holder TAPE RULE RULE DEPTH GAGE This is specially designed to measure the depth of a holes and slots. This is consist of steel head that has a slots to receive a narrow rule RULE DEPTH GAGE CALIPER ( Transferring Tools)  Caliper are tools used to measure a work piece by contact rather than by scale reading. There are two ways; the contact tool is set by the steel rule. This “set” measurements is then used to check a work piece. The method is the reverse of the first. The contact tool is then used to approximate the size the work piece and then this simple length is compared with a steel rule to obtain the measurement.  Different Types of Caliper OUTSIDE CALIPER - It is used to measure the outside surfaces of a round objects. The legs of the instrument is curved outward to accommodate the work piece OUTSIDE CALIPER INSIDE CALIPER It is used to measure the inside diameter of a hole or inside surfaces of the object like slots , keyways and other openings INSIDE CALIPER VERNIER CALIPER The vernier, dial, and digital calipers give a direct reading of the distance measured with high accuracy and precision. They are functionally identical, with different ways of reading the result. These calipers comprise a calibrated scale with a fixed jaw, and another jaw, with a pointer, that slides along the scale. VERNIER CALIPER Parts of Vernier Caliper  The upper jaws of a caliper are used for taking inside measurements such as the diameter of a hole or slot The lower jaws are used for measuring outside dimensions such as width, length and diameter. The depth rod is used for measuring the depth of holes. It protrudes when the thumb screw is turned. The main scale runs along the beam of the caliper. The vernier scale adds an extra degree of accuracy to measurements. The thumb screw is used to precisely adjust the measuring faces of the caliper (both sets of jaws and the depth rod). It helps the user to get a tight grip on the material they are measuring. The lock screw secures the jaws into place, so the object you are measuring can be removed, and readings taken. Micrometer - sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. - Instrument that measures the thickness or the diameter of relatively small parts; it produces finer results than a vernier caliper. Micrometer Caliper Parts of Micrometer  ratchet knob - part that stops the finely threaded screw when the pressure on the object being measured is sufficient. frame - horseshoe-shaped part that supports the anvil and a graduated device from which the measurement is read. anvil - cylindrical part that is attached to the frame of the micrometer to support the object to be measured; the object is placed between the anvil and the spindle. thimble - graduated cylindrical part that is activated by the finely threaded screw and measures the thickness with precision. spindle - cylindrical end of the finely threaded screw. lock nut - ring-shaped part that locks the finely threaded screw in its final position to preserve the measurement obtained. PROTRACTOR A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. Most protractors measure angles in degrees (°). Radian-scale protractors measure angles in radians. Most protractors have 2 sets of numbers, the bottom set is for angles that open to the right and the upper set of the protractor is used to measure angles that open to the left. They are used for a variety of mechanical and engineering-related applications, but perhaps the most common use is in geometry lessons in schools. DIFFERENT TYPES OF PROTRACTOR STEEL PROTRACTOR - It is a tool for measuring angle within one degree. It is convenient to use in laying out and checking angles in some types of work Steel Square is more commonly referred to as the framing square or carpenter's square. It consists of a long arm and a shorter arm, which meet at an angle of 90 degrees (a right angle). It can also be made of aluminum or polymers, which are light and resistant to rust.  Try Square -is a woodworking or a metalworking tool used for marking and measuring a piece of wood. The square refers to the tool's primary use of measuring the accuracy of a right angle (90 degrees).  DIFFERENT TYPES OF GAUGES RADIUS OR FILLET GAUGE It is a thin flat steel tool use for inspecting, checking or laying out work having a given radius. Such a gauge is made in sets of individual gauges for concave ( internal) or convex ( external) radii, or the gauge may consist of the number of leaves, each having a different radii and held in a convenient holder for easy selection and use. RADIUS OR FILLET GAUGE THICKNESS OR FEELER GAUGE Is actually a set of gauges consisting of thin strips of metal of various thickness from 0.0015 inch up to 0.200 inch thick. It is used for checking and measuring bearing clearances and spark plug gaps and many other purposes where a specified clearance must be obtained. THICKNESS OR FEELER GAUGE SCREW PITCH GAUGE Is a gauge for quickly determining the pitch, or number of threads per inch, on a threaded part or in a tapped hole. We can check pitch by simply matching the teeth in the gauge with the threaded part. SCREW PITCH GAUGE References: Machine shop trade secrets by Harvey, James c2013 Handbook of welding and welding technology: basics to application by Smith, Edward, c2013 Fundamentals of Modern Manufacturing Materials, Processes and Systems, Fourth Edition by Mikell P. Groover c2010 Introduction to Basic Manufacturing Processes and Workshop Technology by Rajender Singh c 2006