Workshop Practices PDF

Standards of Workmanship Workmanship Workmanship is the degree of skill with which a product is made or a job done. Within the aircraft maintenance environment, it is a term that takes into account the following factors: The art of skill of a worker. The qu...

Standards of Workmanship Workmanship Workmanship is the degree of skill with which a product is made or a job done. Within the aircraft maintenance environment, it is a term that takes into account the following factors: The art of skill of a worker. The quality of the product. The product or result of the labour and skill of a worker. Attitudes of the AME, team and organisation. Duty of care (self). Duty of care (others). Duty of care (equipment). Working done according to a standard. Workmanship is important for an AME - people put their lives in the hands of AME's every time they fly 2024-06-06 B-07b Maintenance Practices Page 18 of 493 CASA Part 66 - Training Materials Only  Standards of Workmanship Standards are so much a part of our daily routine that we use them without even being aware of doing so, and without giving thought to how they are created or the benefits they provide. A standard is an agreed way of doing something. It can be recorded and published formally, or may simply be a company's informal unwritten procedure. Standards provide benefits to business and to individuals, by defining accurate measurements and lowering production costs; improving product performance, quality, uniformity, interoperability and functionality; and providing a method to improve health, safety, the environment, communications, competition, international trade, and improving the quality of life. Examples of standards may be one of the following types: Private standards are only used by the organisation that developed them. National standards (e.g. Australian Standards [AS]) are produced by a country's National Standards Body (NSB). In Australia, standards are developed together with industry, government and society. Most standards are enforced by regulation and some are voluntary. International standards are produced by the International Organisation for Standardisation (ISO), whose members are the national standards bodies of countries all over the world. Documented standards consult several stakeholders 2024-06-06 B-07b Maintenance Practices Page 19 of 493 CASA Part 66 - Training Materials Only  Tool Control Care of Tools Tools are designed to make a job easier and enable you to work more efficiently. If they are not properly used and cared for, their advantages are lost to you. Regardless of the type of work to be done, you must have, choose and use the correct tools in order to do your work quickly, accurately and safely. Without the proper tools and the knowledge of how to use them, you waste time, reduce your efficiency and may even injure yourself or others. Tools are expensive and vital equipment. When the need for their use arises, common sense plus a little preventative maintenance prolongs their usefulness. Tool control 2024-06-06 B-07b Maintenance Practices Page 20 of 493 CASA Part 66 - Training Materials Only  In general, the following precautions for the care of tools should be observed: Use each tool only for the job it was designed to do. Each type of tool has a specific purpose. If you use the wrong tool when performing maintenance or repairs, you may damage the equipment you are working on or the tool itself. Remember: Improper use of tools results in improper maintenance. Improper maintenance results in damage to equipment and possible injury or death to you or others. Never leave tools scattered about. Always avoid placing tools on or above machinery or on electrical equipment. Never leave tools unattended where machinery or aircraft engines are running. When they are not in use, stow them neatly on racks or in toolboxes. Never use damaged tools. A battered screwdriver may slip and spoil the screw slot, damage other parts or cause painful injury. A gauge strained out of shape results in inaccurate measurements. Clean tools after each use. Oily, dirty and greasy tools are slippery and dangerous to use. Conduct a thorough inventory of tools after use to prevent loss. Remember: The efficiency of aircraft maintenance engineers and the tools they use is determined to a great extent by the way they keep their tools. Likewise, you will be frequently judged by the manner in which you handle and care for your tools; anyone watching will notice the care and precision with which you use the tools of your trade. The care of hand tools should follow the same pattern as for personal articles, that is, always keep hand tools clean and free from dirt, grease and foreign matter. After use, return tools promptly to their proper place in the toolbox. Improve your own efficiency by organising your tools so that those used most frequently can be reached easily without digging through the entire contents of the box. Avoid accumulating unnecessary junk. Tool Control It is a matter of fact – tool control affects safety. When a tool is misplaced on the job, the repercussions can be as minor as investing the dollars to replace it, or as major as the permanent damage that occurs to an engine or aircraft. However, what about the safety risk? The National Aerospace FOD Prevention Inc. estimates the cost of foreign object damage (FOD) to the global aerospace industry at $4 billion annually. These dollars are spent largely repairing aircraft engine damage caused by the ingestion of foreign objects from runways. 2024-06-06 B-07b Maintenance Practices Page 21 of 493 CASA Part 66 - Training Materials Only  Realising this, in an effort to prevent the problem of FOD caused by misplaced tools and the possible cost involved, most aircraft maintenance organisations establish and enforce a Tool Control Program. Tool control procedures are governed by the organisation’s Maintenance Organisation Exposition (MOE), which must be approved in accordance with the CASR 42, 145 and 145 MOSs. The MOE must detail all management procedures for tooling, distribution and return of tooling after use. The issue of tools includes: Record of user; Location of use; and Verification that the aircraft or component is clear of all tools after completion of maintenance. Aviation Australia utilises a shadow-board-and-tool-tag tool control system whereby instructors and trainees are issued a number of ‘tool tags’ and a tag is placed on the ‘shadow’ when a tool is removed. Once the trainee is finished using the tool, it is placed back on the shadow board and the tag is retrieved. Like all good systems, it relies on the honesty and integrity of the workforce to make it a success. The goals of a Tool Control Program are as follows. Objective The primary objective of a tool control program is the safety of personnel and the prevention of aircraft damage which may result from: Lost tools; Damaged hardware; and Miscellaneous rubbish. Responsibility The primary responsibility for the control of tools is with the user. Management should ensure adequate procedures are in place to assist with the control of company and personal tools: Area control; Tool identification; and A FOD critical zone/area. Area Control Helps Tool Control Areas where work controls are implemented should be designated by: Appropriate signs; Floor striping and access; Limitations on personnel required to perform tasks; and A system accounting for all items entering or removed. 2024-06-06 B-07b Maintenance Practices Page 22 of 493 CASA Part 66 - Training Materials Only  Identification of Tools Only tools that have been permanently identified should be allowed or used in a tool control area. This may include colour coding, engraving or other prominent markings. © Aviation Australia Tool order and placement 2024-06-06 B-07b Maintenance Practices Page 23 of 493 CASA Part 66 - Training Materials Only  Tool Control and Foreign Object Damage FOD Critical Zones/Areas Be aware of where you are working. For example, are you working on or near flight controls or engine controls or near engine inlets? Will misplaced tools be a hazard to the safe operation of the aircraft? Control in FOD Critical Areas All items taken into FOD critical areas must be accounted for. Employees’ personal tools should be documented on a tool list, and tools should be transported in a bag or small case. Whether you use tools from a tool board or operate from your own toolbox, a Tool Control Program should be designed and implemented to track tools from the minute they leave the tool board or toolbox to the moment they are returned. For different workplaces, the details of tool control can vary depending on the needs and parts the workshop uses, but usually the basics remain the same. Foreign object damage 2024-06-06 B-07b Maintenance Practices Page 24 of 493 CASA Part 66 - Training Materials Only  Individual Toolboxes Individual toolboxes, at a minimum, should have a method to quickly determine that all tools are accounted for at the end of a maintenance task. This can only be done if each tool has a specific storage location that allows for quick identification if the tool is missing. One method utilises custom foam toolbox inserts that allow technicians to instantly see if a tool is missing. When a tool is removed for use from its perfectly shaped resting place that matches its size, a colour (yellow or red) is revealed beneath to signal that it is out of the toolbox. As long as the top colour of the foam (blue or black) is visible, all tools are present. The foam can be sized to fit any toolbox, and it has the added benefit of reducing tool damage due to improper storage. Individual toolboxes 2024-06-06 B-07b Maintenance Practices Page 25 of 493 CASA Part 66 - Training Materials Only  Shadow Boards Shadow boards are one of the most popular forms of visual management tool control. Many aviation organisations are installing shadow boards, or boards marked with the shapes of tools, to indicate proper tool locations. The shadow board visually conveys two pieces of information: Where the tool belongs Whether the tool is missing from its designated location. This at-a-glance visual indicator can be a real time saver, as it eliminates the need to search through toolboxes, tool drawers or cabinets to find a tool. Posting the shadow board in plain sight of all who use the tools provides immediate feedback as to the status of the tool. Some organisations have taken the shadow board concept a step further by introducing colour- coding. The shadow boards themselves are painted a certain colour, and a matching colour is applied to the tools that belong on them (usually either with paint or durable tape). Typically, each work area is assigned a dedicated colour for its shadow board and tools. One area, for example, may have blue colour-coded tools, another red colour-coded tools and yet another black colour-coded tools. In such a system, it is easy to see if a tool is in the wrong location because a black tool on a red tool board stands out. Photo by Cesar Carlevarino Aragon on Unsplash Tool order and placement - shadow boards 2024-06-06 B-07b Maintenance Practices Page 26 of 493 CASA Part 66 - Training Materials Only  Tool Identification Some maintenance organisations require employees to permanently mark their tools for identification purposes. This provides a way to quickly identify a tool’s owner when one is found. Tools can be marked using a Vibra Peen tool or laser etching. Some other marking methods, such as permanent marker, may not be very effective in a hangar environment. Tool identification - laser etching If your company requires mechanics to mark their personal tools in a uniform method, consider the requirement carefully. For example, it would be better to use engineers’ initials as a tool identification marking rather than company-specific numbers such as employee numbers. If you change to another company, these numbers will not be relevant and you may have to mark them all over again. If employees are required to mark their personal tools, it can be useful to maintain a tool identification log in a central location (Maintenance Control or Quality Assurance, for instance). This log could list all the employees and the identification they are using to mark their tools. This way, if a tool is found, the log can be referenced to find out who owns it. Marking tools serves two purposes. First, it ensures that a found tool is returned to the owner. Second, it helps ensure compliance with missing tool reporting. It makes employees more vigilant in reporting missing tools instead of just going to the closest tool truck or store to buy a replacement. 2024-06-06 B-07b Maintenance Practices Page 27 of 493 CASA Part 66 - Training Materials Only  Tool Inventory A tool inventory should be accomplished regularly so that any missing tools can quickly be identified and searched for before they affect the safety of an aircraft. This can be done after each work task or at least once a day. Many aircraft maintenance organisations choose to do it at the beginning and end of each shift. Tool inventory 2024-06-06 B-07b Maintenance Practices Page 28 of 493 CASA Part 66 - Training Materials Only  Missing Tool Reporting An important part of any tool control program is a process for missing tool reporting. In order to achieve the goal of accounting for all tools to ensure a safe product for the customer, the maintenance culture must encourage employees to report any missing tool. This procedure should be clear about how often tools need to be inventoried, how employees should report a missing tool and the steps to be taken once a missing tool is reported. An important part of this is designating the person who has the authority to release the aircraft in the event a missing tool is not found. Missing tool reporting 2024-06-06 B-07b Maintenance Practices Page 29 of 493 CASA Part 66 - Training Materials Only  Workshop Practices Workshop Materials Many types of workshop materials are available. These include: Greases Oils Solvents Sealants Contact cements Paints Paint strippers. It is important to ensure that a Material Safety Data Sheet (MSDS) and a specification sheet are available for all materials used in the workshop. Workshop materials 2024-06-06 B-07b Maintenance Practices Page 30 of 493 CASA Part 66 - Training Materials Only  Material Storage Storage of flammable materials is an important factor when ensuring safety and maximum usage. Flammable materials such as solvents, paints, paint strippers, contact cements, greases and oils should be stored in an appropriate flammable storage facility when not in use. Some materials are highly toxic, so it is vital to comply with the MSDS for individual materials. This involves, among other things, using PPE and working in a well-ventilated environment. Toxic materials Many aircraft sealants require refrigerated storage to ensure they stay usable for their shelf life. It is important to check the expiry date/shelf life before use. Failure to do so could compromise the integrity of the job being performed. When you have finished using the product, always ensure the container is properly sealed to enable its re-use at a later date. Mixed two-pack sealants need to cure completely before disposal, and then they can be disposed of in accordance with local council/authority regulations. 2024-06-06 B-07b Maintenance Practices Page 31 of 493 CASA Part 66 - Training Materials Only  Sealants 2024-06-06 B-07b Maintenance Practices Page 32 of 493 CASA Part 66 - Training Materials Only  Dimensions, Tolerances and Allowances Dimensions Most aircraft drawings are dimensioned using a reference edge from which all dimensions are made. There are two ways of placing dimensions on an aircraft drawing: 1. Write all dimensions perpendicular to the dimension lines. 2. Write all dimensions parallel to the bottom of the drawing (more conventional method). Dimensions The illustration shows a typical layout of an aircraft drawing. The nominal dimension of an aircraft part is the size stated on the drawing. 2024-06-06 B-07b Maintenance Practices Page 33 of 493 CASA Part 66 - Training Materials Only  Sheet Metal Working A part fabricated from aircraft sheet metal has a maximum and a minimum allowable size. The part is considered acceptable if its size falls within that range. Please note that the double prime symbol (″) represents inches in drawings and dimensional specifications. Tolerance is the difference between the nominal dimension and the upper and lower limits of size, e.g. if the nominal dimension is 5.300 in. and the upper and lower limits are +0.010 and -0.010 in., then the tolerance is said to be ±0.010 in. (± means plus or minus). This tolerance can also be expressed as 0.020 in. This is the upper limit of size minus the lower limit of size (5.310 in. – 5.290 in. = 0.020 in.). In aircraft drawings, any dimension given as a common fraction normally assumes a dimension tolerance of ±1/64 in. Allowance for sheet metal work is the difference between the nominal dimension of a part and its upper limit OR lower limit. The examples below of upper limit and lower limit allowance specify the same dimensional values as above. Upper limit allowance: 5.300 in. + 0.010 in. – 0.000 in. OR Lower limit allowance: 5.300 in. + 0.000 in. – 0.010 in. Precision Cylindrical Parts A precision cylindrical part (e.g. close-tolerance bolt) has a maximum and a minimum allowable size. The part is considered acceptable if its size falls within that range. However, the acceptable range is usually much smaller for mating cylindrical parts than it is for sheet metal repairs. Bolt tolerances 2024-06-06 B-07b Maintenance Practices Page 34 of 493 CASA Part 66 - Training Materials Only  Tolerances and Allowances Tolerance Tolerance is the difference between the nominal dimension and the upper and lower limit of size, e.g. if the nominal dimension is 0.3125 in. and the upper and lower limits are +0.0005 in. and -0.0005 in., then the tolerance is said to be ±0.0005 in. This tolerance can also be expressed as 0.0010 in. This is the upper limit of size minus the lower limit of size (0.3130 in. – 0.3120 in. = 0.0010 in.). Allowance For fits between mating cylindrical parts, allowance is the prescribed difference between the maximum material limits of mating parts. A maximum material limit is the limit of size that provides the maximum amount of material for the part, e.g. the maximum limit of diameter of a bolt and the minimum limit of diameter of its hole. Tolerance Allowance Tolerance Hole Shaft Lower limit Lower limit Upper limit Upper limit © Aviation Australia Allowances and tolerances If the maximum diameter of the bolt is 0.001 in. less than the minimum diameter of the hole, there is a minimum ‘clearance’ of 0.001 in. This is a positive allowance. If the maximum diameter of the bolt is 0.001 in. greater than the minimum diameter of the hole, there is a maximum ‘interference’ of 0.001 in. This is a negative allowance. Note: Tolerance, allowance and types of fit (including clearance and interference fits) are discussed in greater depth in 7.5 and 7.6. 2024-06-06 B-07b Maintenance Practices Page 35 of 493 CASA Part 66 - Training Materials Only  Calibration Standards Precision Tools and Test Equipment Aircraft maintenance organisations are required to regularly inspect and calibrate their precision tooling and equipment. A clear system of labelling indicates to users that the item is within the inspection or calibration period. The label should show: The date last tested When the next inspection or calibration is due, and The authorised person’s signature or stamp. Also, a register should be maintained for all precision tooling and equipment, together with a record of the calibrations and standards used. Inspections and calibrations should be done in accordance with the manufacturers’ instructions except where the organisation can show by results that a different time period is appropriate. Usually, this involves inspections and calibrations being conducted at more frequent intervals but rarely at less frequent intervals. Measuring Equipment Because accurate measurement is essential, engineers and technicians must learn to use various measuring tools correctly and efficiently. Before using a precision measuring tool, ensure that it is within its calibration period for required accuracy checks. (Refer to the calibration tag.) The tool must be calibrated by an approved person or organisation and have a prescribed life limit between calibrations. Before use, it is necessary to ensure the tool will ‘zero’ correctly. It is an offence in the regulated civil aviation industry to use personally owned measuring tools unless they are maintained by an approved organisation and the aircraft operator or maintenance, repair and overhaul (MRO) organisation agrees to the use of such measuring equipment. 2024-06-06 B-07b Maintenance Practices Page 36 of 493 CASA Part 66 - Training Materials Only  Torque Wrenches Torque wrenches are precision measuring tools and should be periodically checked for accuracy – calibration. This is achieved using a torque analyser, which is a mechanical loader that applies a true force at 90° to ensure maximum accuracy. Calibration of torque wrenches and other measuring equipment is carried out by manufacturer-approved organisations employing certified technicians. © Jeppesen Torque wrenches Pressure Gauges and Transmitters Pressure gauges and transmitters are calibrated by hydraulic pumps which use either water or oil, or by pressure generators that use oil or gas. Pressure gauge tester 2024-06-06 B-07b Maintenance Practices Page 37 of 493 CASA Part 66 - Training Materials Only  Micrometers It is possible for a micrometer to slip out of calibration; however, most micrometers can be recalibrated by inserting a precision block – test piece – between the anvil and the spindle. The micrometer is then carefully calibrated by rotating the sleeve with a special wrench until its longitudinal line exactly aligns with the zero mark on the thimble. Note that temperature extremes during the day can affect the calibration process. © Jeppesen Micrometers outside 2024-06-06 B-07b Maintenance Practices Page 38 of 493 CASA Part 66 - Training Materials Only  Calibration Tags Upon completion of calibration checks on all precision tools, a calibration label or tag should be attached to the tool. The label or tag should always be checked prior to using the tool. Calibration labels 2024-06-06 B-07b Maintenance Practices Page 39 of 493 CASA Part 66 - Training Materials Only  Common Hand Tools I (7.3.1) Learning Objectives 7.3.1 Examine common hand tool types (Level 3). Summary This subtopic is part 1 of 3 introducing some of the common hand tools used in aircraft maintenance. 2024-06-06 B-07b Maintenance Practices Page 40 of 493 CASA Part 66 - Training Materials Only  Hammers The Hammer Hammers include different types and weights of hammers and mallets, each with a very specific use. Since misuse of pounding tools can result in damage to aircraft components and injury to personnel, it is important that you always use these tools properly. Before using any hammer or mallet, you should make sure you have the appropriate eye and face protection. Furthermore, you should inspect the tool for any damage that could affect safety. For example, before using a hammer or mallet, make sure the handle is secure and in good condition. When striking a blow with a hammer, think of your forearm as an extension of the handle. In other words, swing the hammer by bending your elbow, not your wrist. Always strike the work squarely using the full face of the hammer. To avoid marring the work, keep the face of a hammer or mallet smooth and free of dents. Hammers 2024-06-06 B-07b Maintenance Practices Page 41 of 493 CASA Part 66 - Training Materials Only  Ball Pein Hammers The ball pein hammer ranges in weight from 28 grams (1 oz) to 1 - 1.5 kg (2–3 lb). One hammer face is always flat, while the other is formed into the shape of a ball. The flat hammer face is used for working metal and driving, but should not be used to drive a nail. The ball end of the hammer is typically used to peen over rivets in commercial sheet metal work. However, this is not the method used for securing rivets in aircraft sheet metal work. Ball pein hammers Cross Pein The narrow cross pein helps gain access to limited working surfaces. Cross pein hammer 2024-06-06 B-07b Maintenance Practices Page 42 of 493 CASA Part 66 - Training Materials Only  Straight Pein The straight pein has a similar form and function to the cross pein, but with a vertical rather than horizontal edge. Straight pein hammer Sledgehammers The metal head of a sledgehammer has two flat faces and is sized according to the weight of the head without the handle. For example, the head of a 5-lb sledgehammer weighs 5 lb. This tool is sometimes used in aircraft maintenance, typically when a lot of heavy driving force is needed, such as when driving heavy pins and stakes. Sledgehammer 2024-06-06 B-07b Maintenance Practices Page 43 of 493 CASA Part 66 - Training Materials Only  Panel or Body Hammers Body or panel hammers have large, smooth faces and are lightweight. They are specifically used to remove small dents and to smooth (planish) or stretch sheet metal. Planishing (from the Latin planus, "flat") is a metalworking technique that involves finishing the surface by finely shaping and smoothing sheet metal. Other types of body hammers include riveting, setting and stretching hammers. Panel hammer 2024-06-06 B-07b Maintenance Practices Page 44 of 493 CASA Part 66 - Training Materials Only  Special Purpose Hammers There are many types of special purpose hammer. The most common in engineering workshops are soft head/face hammers. Soft head hammers are used: to seat or position work for machining to strike surfaces without damaging them to strike full impact blows without danger from rebound. Materials used with soft head hammers include: brass copper aluminium wood rubber plastic rawhide. Copper face rawhide hammer 2024-06-06 B-07b Maintenance Practices Page 45 of 493 CASA Part 66 - Training Materials Only  Plastic soft faced hammer Slide Hammer Slide hammers are used with pullers to ‘shock’ components apart. They are common in aircraft maintenance and range in weight from a few grams to several kilograms. Slide hammer kit 2024-06-06 B-07b Maintenance Practices Page 46 of 493 CASA Part 66 - Training Materials Only  Hammer Safety Safety First Before using any hammer: Ensure that the head is secure and the wedge is in place. Check the head for splits or burrs, which could allow fragments to fly. Check that there are no splits in the handle. Use a clean, dry cloth to wipe your hands and the handle of the hammer. Remove any oil, grease or dampness, which can cause the handle to slip from your hand or the striking face to slip from the work. Top view of ball pein hammers Caution: Never strike one hammer against another because they may shatter. Flying particles may cause injury, especially to the eyes. 2024-06-06 B-07b Maintenance Practices Page 47 of 493 CASA Part 66 - Training Materials Only  Punches The Punch Punches are hand tools that you hit with a hammer. Different punches are made: To mark positions in work To stamp identification marks To drive parts that cannot be hit directly with a hammer To cut holes in thin or soft material. Safe use of punches depends particularly on: Hitting them squarely Keeping their heads free of burrs that lead to mushrooming. Toolbox containing hammers, punches and chisels 2024-06-06 B-07b Maintenance Practices Page 48 of 493 CASA Part 66 - Training Materials Only  Mushrooming After a punch shank has been continuously hammered, the shank end typically deforms to the shape of a mushroom. When this happens, the mushroom shape should be removed and returned to its original crowned shape using a bench grinder. The crowned shape minimises the chance of the punch splitting or chipping by allowing the hammer to hit it squarely. Original crowned shape of a punch shank end Mushroom due to repeated hammering on a punch shank end 2024-06-06 B-07b Maintenance Practices Page 49 of 493 CASA Part 66 - Training Materials Only  Prick Punches Prick punches are small, sharp-pointed punches used to transfer dimensions and locations onto sheet metal for drilling. To mark sheet metal work, place the prick punch in the desired position and then tap the head of the punch with a small hammer. Because prick punches scar the material and have relatively delicate points, they should never be used to drive a pin or rivet from a hole. For example, the witness marks may be used to locate pivot points of dividers for scribing lines or arcs. Prick punch Prick punch use 2024-06-06 B-07b Maintenance Practices Page 50 of 493 CASA Part 66 - Training Materials Only  Centre Punches Centre punches are similar to prick punches, but they are generally larger, are ground to a shallower angle and are hit harder. Centre punches are used to: Make deeper witness marks on scribed lines Locate a centre position and make it easier for a drill point to start cutting accurately in that position Mark relative positions of adjacent parts that have to be removed and replaced. Automatic centre punch (left) and solid steel centre punch (right) Centre punch use 2024-06-06 B-07b Maintenance Practices Page 51 of 493 CASA Part 66 - Training Materials Only  Starter Drift and Pin Punches A starter drift punch is hit hard with a hammer to jar loose taper and parallel pins. A starter drift punch tapers towards a slightly concave end that will not spread the end of a pin. A pin punch is hit with a hammer to drive loosened locating or locking pins, dowels and rivets out of their holes. The ends of these punches are circular and flat. Parallel pin punch set Pin punch use When working on aircraft, care must be taken not to damage the component by using steel punches and drifts – a better choice is a soft drift material such brass, aluminium or nylon. 2024-06-06 B-07b Maintenance Practices Page 52 of 493 CASA Part 66 - Training Materials Only  Brass (left) and Nylon (right) punches Letter and Figure Punches These hardened and tempered steel punches are used to stamp identifying symbols, letters or numbers, as required, on work. Number/letter punches Caution: All working edges of punches should be kept sharp. All mushroomed material should be ground off the shank end to prevent eye injury. 2024-06-06 B-07b Maintenance Practices Page 53 of 493 CASA Part 66 - Training Materials Only  Holding Tools Pliers Pliers include a group of tools which have a pair of legs joined by a pivot, hinge or fulcrum pin. These tools may have three types of joints: Fixed Toggle or compound Slip. Pliers are: Made of high-carbon tool steel or alloy steel that is forged, machined and heat treated Classified by type and length Provided with handles shaped to give an efficient grip for the hand Made with a great variety of jaw shapes designed for cutting, holding, gripping, pulling, pushing, twisting or turning. Pliers 2024-06-06 B-07b Maintenance Practices Page 54 of 493 CASA Part 66 - Training Materials Only  Multi-Grips Multi-grips pliers are used to tighten the packing gland nut around a water pump shaft. They have several curved grooves that make up a series of interlocking joints. Furthermore, the length of the handles allows a great deal of force to be applied to the jaws. Interlocking joint pliers are available in lengths from around 5 in. up to about 20 in. Multi-grips Vise-Grip Locking Pliers Vise-Grip is the registered trade name of the Petersen Manufacturing Company for a special compound-action type pliers. The opening of these jaws is adjustable by a knurled screw located in the end of the pliers’ handles. When these handles are squeezed together, compound leverage multiplies the effort and applies a tremendous force to the jaws. A toggle action clamps the jaws together so they will not open when the handles are released. The jaws are released by a small lever in one of the handles. Vise-Grip pliers come in a wide variety of lengths and jaw styles. Some are designed to hold pipes, some to cut wire and others to pinch off hoses. Special forms of Vise-Grip pliers are made with sheet metal bending jaws, while others are made with jaws that serve as welding clamps or C-clamps. Locking pliers 2024-06-06 B-07b Maintenance Practices Page 55 of 493 CASA Part 66 - Training Materials Only  Duckbill Pliers A special type of pliers used in aviation is the duckbill pliers. These long-handled, flat-nosed pliers are typically used to twist and help remove safety wire. The jaws of duckbill pliers have serrations to grip safety wire, while the handles are long enough to provide a good tight grip on the wire while it is being twisted. Duckbill pliers Lockwire Pliers/Safety Wire Pliers A special tool used by aircraft engineers is the lockwire pliers. This tool combines the features of side- cutters with those of the duckbills. Lockwire pliers have a special twister built into the handle that quickly and efficiently twists lockwire. To lockwire something, cut the length of wire needed and insert it into whatever is being safetied. Cross the wire close to the head of the object being safetied and grip the ends of wire with the flat serrated jaws. After locking the handles together, pull the knob in the pliers handle and a spiral rod in the handle will rotate the pliers, twisting the wire. When twisting is completed and the wire is secured, cut off the ends of the wire with the built-in cutters and put a ‘pig tail’ or curl on the end of the wire to avoid injury to personnel. Lockwire pliers/safety wire pliers 2024-06-06 B-07b Maintenance Practices Page 56 of 493 CASA Part 66 - Training Materials Only  Needle Nose Pliers Several different designs of needle nose pliers are used in aviation maintenance. Needle nose pliers come in handy for electrical and electronic work because they are typically small enough to grip and hold small components and wires. Some needle nose pliers have long, thin jaws that are bent at a right angle to the handle. This allows the pliers to grip a component and hold it while keeping your hand out of the way. Needle nose pliers 2024-06-06 B-07b Maintenance Practices Page 57 of 493 CASA Part 66 - Training Materials Only  Circlip Pliers The circlip pliers shown below are used for fitting and removing circlips in assembly and maintenance work. Some types are made to suit inside or outside circlips, and the noses can be straight or bent. Circlip pliers 2024-06-06 B-07b Maintenance Practices Page 58 of 493 CASA Part 66 - Training Materials Only  Chisels Cold Chisels Flat cold chisels are made from square or octagonal stock, ranging from 8 - 17 mm (5/16 - 11/16 in.) across. The cutting edge of a flat chisel is forged so it is slightly wider than the shank and is ground to an angle of approximately 70°. To use a cold chisel, hold the cutting edge flat against the material and control the depth of the cut by varying the angle between the chisel and the work. The cutting edge of a flat chisel is ground slightly convex so that the greatest stress from a hammer blow is directed into the centre of the chisel. This reduces the stresses that are transmitted to the sides of the cutting edge. Flat cold chisel set Cold chisels are not regularly used in aircraft maintenance as they are not suited to most aviation maintenance tasks. In fact, most engineers probably do not have one in their toolbox and have not used one in their careers. 2024-06-06 B-07b Maintenance Practices Page 59 of 493 CASA Part 66 - Training Materials Only  Files Files and Filing Next to the chisel, the simplest cutting tool is the file. A file differs from a chisel in that it has a large number of cutting edges or points rather than a single cutting edge. A file is pushed across a material by hand, and as it moves, the teeth act like small chisels, removing small chips of material. Files are generally manufactured from high-carbon steel. They are available in a variety of lengths, sections, cuts and grades to suit almost every requirement. A file’s large numbers of small teeth can cut softer materials. Pressure on the file makes its teeth penetrate the surface to be filed. When the file is moved in the cutting direction, small particles are removed from the surface being filed. The file is one of the most commonly used tools, but as there is such a large range of types, shapes and sizes, you must know the correct file for the job at hand. 2024-06-06 B-07b Maintenance Practices Page 60 of 493 CASA Part 66 - Training Materials Only  Parts of a File To obtain the best results, you should be familiar with the parts of a file: The tang, on which a handle should always be fitted, is not hardened like the body of the file. The heel is the portion between the tang and the teeth. The faces are the main surfaces on which the teeth are cut. The edges are two sides, mainly on flat files, on which teeth may or may not be cut. The point is the end opposite the tang. The back is the convex side of a half-round or similar file. A safe edge is an edge on which no teeth are cut. This permits a corner to be cleaned out without damage to adjacent faces. Parts of a file Files can provide either: A roughing process to alter the size of a part by removing a considerable amount of material A finishing process to smooth a surface without removing much material. Flat or curved surfaces may be produced by varying the direction of the cutting motion. Both the shape of the teeth and the number of teeth affect the surface finish obtained by filing. 2024-06-06 B-07b Maintenance Practices Page 61 of 493 CASA Part 66 - Training Materials Only  File Characteristics The rate of cutting and the finish given to the work are mainly determined by the depth and spacing of the file’s cutting teeth. Grade of Cut The cut of the file refers to how fine its teeth are. They are defined as (from roughest to smoothest): rough, middle, bastard, second cut, smooth, and dead smooth. Type of Cut Various arrangements of cutting teeth are provided to give the most satisfactory results when you work on different metals. These arrangements are known as cuts. Details of the more widely used cuts are as follows: Single-cut Double-cut Dreadnaught (curved teeth) Rasp. Single-cut file has one set of parallel teeth while a cross-cut or double-cut file has a second set of cuts forming diamond shaped cutting surfaces. 2024-06-06 B-07b Maintenance Practices Page 62 of 493 CASA Part 66 - Training Materials Only  Cut Usages Although there are rougher cuts, the following are the three standard cuts in regular use. Bastard Cut The coarse bastard grade of file removes material quickly. It is intended for roughing out. Second Cut The second cut grade is finer than the bastard grade. It cuts more slowly, but gives a smoother finish to the work. Smooth Cut A smooth file cuts quite slowly and imparts a good finish to the work. It should be used for finishing work. File cuts and cut types 2024-06-06 B-07b Maintenance Practices Page 63 of 493 CASA Part 66 - Training Materials Only  File Types and Profiles Flat Files The flat is the most commonly used section for general filing. In most cases, the blade is a rectangular shape, but tapered and bellied blades are also available if required. © Commonwealth of Australia 2009 Flat file Hand Safe Edge Files The only difference between flat and parallel files is that they have one safe edge, that is, an edge without teeth. They are used for filing near 90° shoulders to avoid damaging the finished surface of the shoulder. © Commonwealth of Australia 2009 Hand safe edge file 2024-06-06 B-07b Maintenance Practices Page 64 of 493 CASA Part 66 - Training Materials Only  Half-Round Files Half-round files are shaped like segments of a circle. They are double-cut on the flat side. The teeth on the convex side may be either double- or single-cut, depending on the grade and length of file. They are used for enlarging large, round holes and for filing concave surfaces. The flat side may be used for filing in corners and grooves where the angle is less than 60°. © Commonwealth of Australia 2009 Half-round file 2024-06-06 B-07b Maintenance Practices Page 65 of 493 CASA Part 66 - Training Materials Only  Round Files A round file is suitable for filing small radii and is used with bellied, tapered and parallel blades, the bellied shape being the most common. Most round files are single-cut in a spiral fashion. The smaller sizes of round taper files are called rat tails. They must be used with an additional rolling motion to prevent grooving the work. They are used for enlarging round holes and finishing fillets and other concave surfaces. © Commonwealth of Australia 2009 Round file Three-Square Files Three-square files have a cross-section that is an equilateral triangle. They are usually of bellied form and have limited use in clearing out square corners and filing acute internal angles greater than 60°. © Commonwealth of Australia 2009 Three-square file 2024-06-06 B-07b Maintenance Practices Page 66 of 493 CASA Part 66 - Training Materials Only  Square Files All three of the usual shapes are associated with files of square cross-section. They are suitable for internal work, such as filing keyways, and for enlarging square and rectangular holes. © Commonwealth of Australia 2009 Square file Warding Files Warding files are very thin and taper markedly in width. They are used for very narrow slotting. © Commonwealth of Australia 2009 Warding file 2024-06-06 B-07b Maintenance Practices Page 67 of 493 CASA Part 66 - Training Materials Only  Sheet Metal Shears Aviation Snips The popular tin snips are useful in aircraft maintenance work for cutting the metal to its rough shape and size, but for accurate work, it is best to use aviation snips. Aviation snips have serrated cutting edges and leverage multiplication that allows relatively thick sheet metal to be cut without requiring excessive handle force. They come in sets of three, and the handles are colour coded: yellow cuts straight, green cuts to the right and red cuts to the left. Aviation snips 2024-06-06 B-07b Maintenance Practices Page 68 of 493 CASA Part 66 - Training Materials Only  Cutting Pliers Diagonal cutting pliers (or side cutters) are: Made with jaws set at an angle Obtainable with bare or insulated handles Used for shearing off wires in confined spaces and cutting off wires close to electrical terminals Useful for pulling, cutting to length and spreading cotter pins. Diagonal side-cutters Side cutter use 2024-06-06 B-07b Maintenance Practices Page 69 of 493 CASA Part 66 - Training Materials Only