CHAPTER - 17

Hand Tools and Portable Power Tools

1. Statutory Provisions2. Indian Standards3. Hand Tools :

3.1 Causes and Control of Tool Accidents

3.1.1 Main Causes of Tool Accidents

3.1.2 Control of Tool Accidents3.1.3 Ergonomic Design of

Hand Tools3.2 Types & Safe Use of Hand

Tools-Metal cutting, Wood cutting,

Material handling, Torsion, Shock, Non- sparking and Miscellaneous tools.

3.3 Centralised and Personal Tool Issue System

3.4 Purchase, Storage and Supply of Tools

3.5 Causes of Tool Failure3.6 Inspection, Maintenance and

Repairs of Tools

3.7 Tempering, Safe Ending, Dressing

and Handles of Tools4. Portable Power Tools :

4.1 Types, Hazards and Safe Use4.2 Selection, Inspection,

Maintenance and Repairs

4.3 Use of Personal Protective Equipment

1 STATUTORY PROVISIONSSection 36A of the Factories Act

states that portable electric appliance (any tool, equipment or instrument) when used in any confined space (tank, vat, chamber, pit, pipe, flue etc.), shall be of low voltage up to 24 Volt only, or other safety device like ELCB should be provided.

If inflammable gas, fume or dust is likely to be present in such confined space, portable lamp or light should be of flameproof construction.

Clause (5), Part III of Schedule XIX, Chemical Works u/r 102 of the Gujarat Factories Rules requires all tools and appliances for work in flammable area of non-sparking type. Similar provision is also required under clause (5), Schedule XXI, Solvent Extraction Plants, under the same rule.

2 INDIAN STANDARDS

Some IS are : Safety procedures in hand operated tools 8235 (PED5), SP-53. Tools - for hand, footwear 6053, handles wooden 620, handling device 4676, mason’s 1630, metal cutting 10097, metal forming 6652, mining - tungsten carbide 4005, non-sparking 4595, planning 6075, 8842, threading 8778, pneumatic 5651, portable - motor operated 4665, rotating 1850, shanks - taper and automatic changers’ 11173, numerically controlled machine tools 11172, steel high speed 7291, turning and planning 1983, universal, test chart 3080.

Tool and die - hot work 3748, cold work 3749, press sets of, guide posts 7664, broaching 7773.

See Part 2.3 of Chapter-15 and Part 3 of Chapter-25 also.

3 HAND TOOLSNo work is finally possible without

hand-held or hand operated tools. Such tools are of many types, having many

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THEME

purposes and operated by hand only or by some energy e.g. electric, pneumatic, hydraulic etc.

3.1 Causes and Control of Tool Accidents:

Causes of tool accidents and their safety aspects including ergonomic design are important -

3.1.1 Main Causes of Tool Accidents:

Table 5.8 in Chapter-5 states that in India, injuries due to Hand Tools were 9 fatal and 10571 non-fatal i.e. total 8.25% in 1990 and 5 fatal and 3314 non-fatal i.e. total 5.47% in 1991.

Table 5.20 states 9 & 12 fatal accidents due to hand tools in Gujarat in 1996 & 1997. This comes to 4.91% & 4.89% respectively. The last raw of Table 5.22 indicates that hand tool accidents (Causation No. 124) were 4.52% (710 out of 15683) in Gujarat in 1994. Thus hand tools accidents vary from @ 4 to 8% each year which need to be controlled.

USA figures of deaths due to cutting or piercing instruments or objects were 103, 108 and 132 in the year 1994, 1993 and 1992. Percentage wise these were 0.11, 0.15 & 0.15 respectively. (Accident Facts, 1997, NSC).

The causes and effects of hand tools accidents are eye injuries due to flying chips from tools, puncture wounds and infections, cut injuries due to knives, chisels and hammers, bone fractures due to defective or slipping wrenches and scratches due to scrap etc., cutting of fingers, tendons and arteries, contusion etc.

Poor maintenance, incorrect tool, wrong use, carelessness, bad storage and poor material are main causes of tool accidents.

3.1.2 Control of Tool Accidents :

The main control measures are:

1 The right tool for the right job: Wrong methods are: To use file instead of pry, wrench instead of hammer, pliers instead of wrench etc. This may cause accident. Therefore it should be avoided.

2 Tools in good condition : Examples of poor condition are : Hammers with loose handles, screw drivers and cutting tools with broken points or broken handles, wrenches with cracked or worn jaws, dull saws, and flexible electric cables with splint insulation, broken plugs, unearthed ground wire etc. Such conditions should be removed.

3 Tools used in the right way: Wrong ways are : Screw drivers applied to job (e.g. to open a lid, to remove bearing), knives pulled toward the body and failure to ground electrical equipment. Tools should be used in right way.

4 Tools kept in a safe place and safe way: Unsafe practices are: Tools kept overhead so as to fall; chisels and other sharp tools kept in pocket or left in tool boxes with cutting edges exposed. They should be kept in a proper way.

5 Good housekeeping for orderly layout and cleanliness: Haphazard lying of tools anywhere, leaving tools at the workplace after completion of the job, slippery surface not cleaned, tools kept in aisles or walkways etc. are common causes of tool accidents. Tools should be kept orderly.

The supervisors and workers should be trained:

1. To wear safety goggles, face shield, helmet etc. as per requirement.

2. To select the right tools for each job and their right use. To return the tools after use.

3. To guard, inspect, repair and maintain tools in safe condition.

4. To use the proper storage facilities in the tool room and on the work place.

5. To put the tools in such a way that they can be readily available.

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6. To scrap and replace the tools when worn.

7. To check out tools at cribs.8. To store in safe condition when not in use.

3.1.3 Ergonomic Design of Hand Tools

Ergonomic design of hand tools takes into consideration that they should :

1. Effectively perform the intended function.

2. Be properly proportioned to the dimensions of the user.

3. Be appropriate to the strength and endurance of the user.

4. Minimise user’s fatigue.5. Provide sensory feedback.

Some biomechanical factors to be considered in tool design are grasp, handedness (left or right, single or double), hand strength, sex and clothing.

Criteria affecting handle design are its shape, diameter, length, angulations and texture. Specific criteria are - diameter, shape, weight, section, length, angulations of and placement of handle for hammer.

Screw drivers, pliers, saws and power tools are important for ergonomic design.

3.2 Types and Safe Use of Hand Tools:Main types of hand tools are as under

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(A) Metal Cutting Tools :

These are chisels, stamping and marking tools, tap and die work, hacksaws, files, hand snips and cutters.

Factors of selection and safe use are : Materials to be cut, size and shape of the tool, depth of cut, sponge rubber shield or combination of rubber hand grips and shields on hammer struck tools, use of chisel holder or tong, safety goggles, vice, wrench, right type of file with smooth handle, lubrication on cutters etc.

The flat chisel should have its cutting edge slightly convex. All chisels (flat, cold, diamond point or cape type) should be strong enough so as not to bend when struck. Striking face of the hammer should be slightly larger (9 mm by dia) than the struck face of the chisel. Bull chisel should be held by tongs or chisel holder to save the holder from injury.

Stamping and marking tools should be held by tool holder to keep fingers away from the tool being struck.

In tap and die work, hands should be kept away from broken tap ends and threads being cut.

Hack saws should be properly tightened in the frame to prevent buckling and breaking. Select proper blade (teeth per inch) for the proper metal (hard or soft) to be cut. Pressure should be applied on forward stroke only. Cutting speed of 40 to 60 strokes per minute is proper.

Selection of correct file for the job can prevent injuries, increase production and file life. A file should not be hammered or used as a pray. It should not be used as a punch, chisel or other tool because the hardened steel may fracture in that way.

Jaws of hand snips should be kept tight and well lubricated. Do not hammer on the handles or jaws of the snips. Safety goggles and leather or canvas gloves are necessary.

Cutters should be used to cut at right angles only. They need frequent lubrication and should not be used as nail pullers or pray bars.

(B) Wood Cutting Tools :

These are wood chisels, saws, axes, adzes and hatches.

Factors of safe use are : Proper method of holding and using the tool, splinters free handles, nail detection, sheath or metal guard on axe blade, use of safety goggles, sharp and proper cutting angle. Do not drop the tools.

The wood to be cut should be free of nails to avoid damage to the cutting edge. A wood chisel should not be used

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as a pry or wedge, otherwise the hard steel may break.

Proper saw (crosscut or ripping) should be selected. When not in use, saws should be wiped off with an oily rag and kept in racks or hang by handle. Nails should be cut by metal cutting saws.

Axes and hatches are designed to cut, trim or prune trees and soft wood. Their cutting edges should not strike against metal, stone or concrete. A narrow - bladed axe is used for hard wood and a wide axe for soft wood. Safety shoes, goggles and thick pants should be worn while using an axe.

Adzes are hazardous tools and should be used by trained workers only. Safety shoes, shin guards and safety goggles are necessary. When not in use, it should be set aside in a safe place with its cutting edge covered or left stuck in the timber.

(C) Material Handling Tools :

These are crow bars, jacks, hooks, shovels and rakes.

Factors of safe use are : Proper size and type of the tool and its handle, solid footing and lubricating of jack, shielded point of the hook, trimmed edges and polished handles of shovels.

A crowbar has a point toe to grip the object to be moved and a heel to act as a pivot or fulcrum. Sometimes a wooden block may be placed under the heel to prevent the crowbar from slipping and injuring hand.

Hooks should be sharp so that they should not slip when applied. Handles should be strong and properly shaped and attached.

Shovels should be used by proper leg positions so as not to lose balance. Edges should be trimmed and handles without splinters.

(D) Torsion Tools :

These are adjustable wrenches (spanners), pipe wrenches, pipe tongs, machine wrench, torque wrenches, socket wrenches, open end or box wrenches, pliers, tongs, special cutters, nail band crimpers and screw drivers.

Factors of safe use are : Sharp jaws of wrenches, inspection of adjusting nut of the wrench, correct size of the wrench and not to change its dimension, insulated handles of electricians’ pliers and screw drivers and screw driver not using for other purposes. A screw driver tip must be properly ground. The user should not lose balance on slipping of tool or the job.

Box and socket wrench (spanner) completely encircles the nut, bolt or fitting and grip it at all corners as opposed to the two corners grip by an open-end wrench. They cannot easily slip.

Wrench capacity should not be overloaded by using pipe extension on the handle or striking the handle as normally bus drivers do. For heavy duty work, sledge-type box wrenches are available. Penetrating oil (kerosene) should be used first to loosen tight nuts.

The use of the wrong size wrench can round the corners of the bolt or cause slippage and make its subsequent use difficult. Makeshift approach is not good.

Adjustable wrenches should be used for light duty jobs where no fixed spanner is available.

For the reason of safety, wrenches should be pulled toward the self and not pushed.

Pipe wrenches should be prevented from slipping and falling. Its adjusting nut should be checked frequently. If it is cracked, the wrench should be withdrawn from the use. A pipe wrench should be used for pipes and their fittings only and not for nuts and bolts because their corners can break the teeth of the wrench, thereby making it unsafe to use later for pipe work. It should also not be used for soft metal (brass, copper) valves or fitting which can be crushed or bent out of shape.

Pliers are meant for gripping and cutting operations and should not be used as wrenches. A guard cover on cutting edge of side-cutting pliers can prevent flying short ends. Pliers for electrical work must be insulated and simultaneous use of electrician’s shock-proof gloves is also necessary.

Pullers are used to pull out gear, wheel, pulley, bearing etc. from a shaft.

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Prybars and chisels should not be used for this purpose.

Screwdriver tip must be properly ground to fit the slot and it should be of the correct size for the head. Handle should not be hammered. For electrical work, handle should be insulated. Screws should not be overtightened to avoid slipping.

(E) Shock Tools :

These are hammers, sledge hammers, riveting hammers, carpenter’s or claw hammers. The handles should be smooth and of proper size.

(F) Non-Sparking Tools :

Such tools of non-ferrous (Beryllium, copper alloy, brass, copper, lead, plastic, rubber) materials are used where flammable gases, volatile liquids and explosive substances are stored or used. They should be kept free of picked up foreign particles to avoid friction sparks.

They cannot be used to apply heavy stroke. Therefore careful use is necessary. It should be properly selected.

(G) Miscellaneous Cutting Tools :

Planes, scrapers, bits, drawknives, ice picks and brad awl are used for special purposes.

Knife accidents are many. A handle guard or finger ring on the handle of knife and the cutting stroke away from the body are desirable. Knives should be carried over the right or left hip toward the back. This will prevent severing a leg artery or vein in case of fall. Knives should not be kept mixed with other tools. Knives should not be used in place of screwdrivers, can openers or ice picks.

All such tools should be kept sharp and in good condition. When not in use, they should be placed in a rack on the bench or in a tool box in such a way that will protect the user as well as the cutting edge.

Carton cutters are safer than hooked or pocket knives for opening cartons as they eliminate deep cuts that could damage inner contents.

While walking or climbing on ladders, workers should use a strong bag, bucket, tool hoist belt or pouch to hold tools safely and to keep both hands free for safe moving and working. Sharp tools should not be put in pockets. Tools shall never be thrown on ground. Tools should not be put on vibrating or slippery overhead surfaces, ladder step, scaffold plank, overhead piping or part of any structure or machine from which they can easily fall or hurt.

While giving tool to another person, the handle should be toward the receiver. While turning around, care should be taken not to strike others.

Misuse of hand tools can cause injuries. Use of hand tool with power driven machinery (e.g. lathe) should be controlled. Training is necessary for their safe handling and use. Use of safety goggles and setting up a shield or screen to prevent injury to others from flying particles, sparks, excessive light, radiation etc. are also required.

Indian Standards should be followed for design, selection, use and maintenance of above tools. See Part 2.

3.3 Centralised and Personal Tool Issue System :

The main advantage of such tool control is the uniform inspection and maintenance of tools by a trained man. It facilitates the effective records of tool failure, accident causes and suggestions for improvement. It provides positive control than scattered storage. Tools are well maintained and less exposed to damage, deterioration and falling hazards.

The central tool control room attendant can advise and issue the right type of tool, ask to return the damaged or worn tool and encourage the safe use of tools. He can also suggest the appropriate type of personal protective equipment at the time of issuing the tool and make arrangement to get clean and to well maintain the tools after and before issue.

Methods of service, repair and reconditioning should be established.

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Supervisors should frequently, at least weekly, inspect all tools and remove from service those found damaged. A checklist of inspection can also be designed and used.

It is the employer’s responsibility to see that the employees are provided with and use the safe tools in safe methods.

3.4 Purchase, Storage and Supply of Tools :

Careful purchase of hand tools can eliminate hazards from beginning. Standard (IS & others) and approved type of tools should be ordered for purchase. Material of construction, quality, durability, ergonomic design, good handle and insulation, effective cutting edge and electrical safety with electrical tools are some of the points for better selection. Purchase of tool boxes, chests, cabinets, belts and pouches also needs attention. In-charge of a central purchase department should fix the criteria or guidelines for best quality tools. Advice of the safety committee and experienced supervisors and workers should also be taken.

Storage of tools should be in a dry cool place and away from any chemical effect. Tools should be kept in a tool box. Proper cupboard, rack or shelves should be used to put tool boxes. Shelves may be movable so that workers can reach all sections to get their tool boxes out.

Tool boxes should be used to put and carry the tools. A tool box should have handle, catch or a hasp and locking arrangement. Bigger tool boxes having more drawers or trays are called tool chests. Mobile tool cabinets are bigger tool chests and move on wheels. Depending on size, weight and number of tools, proper type of tool box, chest or cabinet should be selected.

Supply of tools may be from a central tool room or through supervisors on need-base system or allotted to the worker to keep with him in his tool box. It should be ensured that the tool should be of good quality and in safe and good working condition. Supply includes replacement of damaged or worn tools. A

record of purchase date, service condition, repair and maintenance can be useful in this regard.

Tools should be in sufficient number so that it can be supplied or replaced individually and work is not suffered because of any waiting time. If this is not possible, working time of the tool should be so scattered and planned to minimise the waiting period. Time of supply should be during working hours and suitable to the workers.

3.5 Causes of Tool Failure :They are : overheating or under

heating of the forging of steel when it was hardened, cracks from improper forging, improper tampering, failure to relieve stresses in forging, improper quenching, incorrect angle of cutting edge or steel of poor quality.

Defects of these types will be found in tools of inferior construction, which, because of breakage and inefficiency, are more expensive in the long run than are tools of the best quality obtainable.

3.6 Inspection, Maintenance and Repairs of Tools :

The tool room attendant or tool inspector should be qualified by training and experience to pass judgement on the condition of tools for further use. No dull or damaged tools should be given for work.

Efficient tool control requires periodic inspection of all tool operations. Responsibility for such periodic inspection should be placed with a top man, preferably the department head and should not be delegated by him.

Hand tools receiving the heaviest wear, such as chisels, wrenches, hammers, sledges, star-drills, blacksmith’s tools and cold cutters require frequent maintenance on a regular schedule.

Repair facilities require work benches, vices, hardening or tempering furnace or forge, tempering baths, goggles, repair tools, grinders, fasteners and good lighting. Enough stock should be

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maintained to replace and issue safe tools.

3.7 Tempering, Safe Ending, Dressing and Handles of Tools :

Tempering of Tools : Hammer-struck and striking tools (chisels, stamps, punches, cutters, hammers, sledges and rock drills) should be made of carefully selected steel and heat-treated so that they are hard enough to withstand blows without mushrooming excessively and yet not be so hard that they chip or crack.

For safety, it is better that shock tools, some of which can be dressed frequently, be a little soft rather than too hard, because a chip may fly from an excessively hard tool without warning when the tool is struck with a hammer or sledge.

Forming and tempering of tools is a skilled operation. Before heat-treating any tool, the exact analysis of tool or recommendations for its proper heat treatment should be obtained.

Safe-ending of Tools : Hammer-struck tools, such as chisels, rock drills, flatters, wedges, punches, cold cutters and number dies should have heads properly hardened by a qualified workman. The hazard of burred heads can be reduced by safe-ending the tool. This can be quickly and economically achieved by grinding or flame-cutting a shoulder recess about 1/8 inch wide and 1/4 inch deep into the tool head and then bronze-welding it. The proper base-metal temperature for bronze-welding is 16000

to 17000 F. The correct temperature is indicated by a bright red colour when the tool is looked at through dark glasses in the light of oxyacetylene flame.

Short sections of tight-fitting rubber hose can also be set flush with the striking ends of hammer-struck tools to keep chips from flying.

Dressing of Tools : Shock, cutting and pointed tools require regular maintenance of their edges or striking surfaces. Once the cutting or striking surfaces have been properly hardened and tempered, only an emery wheel,

grindstone, file or oilstone need be used to keep the head in shape and the edges clean and sharp. Proper precautions should be taken before grinding hardened tools. They should not be ground until they have been drawn or tempered. Grinding should be done in easy stages with no attempt to take off much metal at one time. While grinding, the tool should be kept as cool as possible with water or other cooling medium. The manufacturer’s recommendations for type and kind of grinding wheel should be followed. Each cutting edge should have the correct angle according to its use and be finished off with a file.

Redressing of Tools : Redressing or reshaping of tool edges or surfaces which are badly damaged is not recommended. It should be discarded.

Procedure for correct redressing of dull cutting edges is as under :

1. The tool edge should be supported firmly.

2. File or stone away from the cutting edge. Do not use a grinding wheel.

3. Restore the original contour of the cutting edge.

Handles : The handles of the tools should be of the best straight-grained material. Fitting of handles is very important. Poorly fitted handles make it difficult for the worker to control the tool. Design criteria for handle are its shape, diameter, length, angulations, texture and ergonomic aspects for convenience and safe use.

Handles should be fitted or replaced by an experienced person. Long use or shrinkage can loosen the handle. Wedges can be inserted in gap, tool head can be further driven in the handle with wedges reset and the protruding end of the handle cut off. If this is not possible a new similar handle should be fitted after removing the old one.

4 PORTABLE POWER TOOLS4.1 Types, Hazards and Safe Use :

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Portable power tools are divided into five primary groups according to the power source : electric, pneumatic, hydraulic, gasoline and explosive (powder actuated). Several types of tools such as saws, sanders, drills, and grinders are common to the first three groups; whereas explosive tools are used exclusively for penetration work, compression and cutting. Pneumatic grinders, impact tools and flexible shafts tools are also in use. Hydraulic tools are used mainly for compression work.

A portable power tool presents similar hazards as a stationary machine of the same kind, in addition to the risks of handling. Typical injuries caused by portable power tools are burns, cuts and strains. Sources of injury include electric shock, flying particles in the eyes, fire, falls, explosion of gases and falling tools.

The power line should always be disconnected before accessories on a portable tool are changed, and guards should be replaced or put in correct adjustment before the tool is used again.

Care should be taken to set power driven tools in safe area where they may not be struck by passers-by and activated. A tool should not be left in an overhead place where there is a chance that the line, if pulled, will cause the tool to fall.

Flexible cords, cables or hoses should be hung overhead and on safe points, and not over nails, bolts, sharp edges, oil, hot surfaces and chemicals. They should be frequently checked for cracks, opened joints, cut phases or earth wires.

Electric Tools :

Electric shock is the chief hazard from electrically powered tools. Types of injuries are electric flesh burns, minor shock that may cause falls and shock resulting in death.

Main safety points for electric power tools are :

1. Flexible cable (cord) should be protected from misuse, abuse and damage to insulation resulting in broken or exposed live conductor.

2. Plug-socket connection should be tight and safe. No bare conductors should be inserted in plug. Three pin top should be used.

3. Metal casing should be effectively earthed. Earth core of the flexible cable should be properly connected to the metalwork to be handled. Flexible conduit is not suitable for this purpose.

4. Second alternative is the use of 110 V supply with centre tapped to earth to reduce an effective shock voltage to 55 - a relatively safe voltage.

5. Power cutting switches should be within reach and near the apparatus.

6. Regular maintenance to check earth core continuity and strength of earthing.

7. Additional back-up protection is ELCB. i.e. earth leakage circuit breaker which detects the current difference between power supply line and current returning to the supply point. In normal safe operating condition, this current difference is zero but if there is a fault and leakage starts to earth, a differential current occurs which operates the device that rapidly senses and trips its contacts to cut off power to the apparatus. See Part 6.2.3 of Chapter – 11.

8. Electric tool should never be put in wet area or used in raining condition.

9. Double protection or double-insulated or all insulated type equipment which need not be earthed.

10. Dead man control. This tool operates till the button is pressed and it stops as the button is released. Portable saw, hoist and remote control pendant are of this type.

While using electric drills, saws and grinding wheels, eye protection is always required. Drill bit should not be of excessive length, otherwise it may break. Electric saws should have guards. Circular saw (portable) should be equipped with a trigger switch that shuts off power when pressure is released. It will not run when not in use. Grinding wheel should be properly mounted and guarded.

Sanders should run away from the body as it cannot completely guarded. Dust should be cleaned daily by a low

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pressure (30 psi or less) air and wearing safety goggles. Vacuum cleaning equipment is safer.

Pneumatic or Air-powered tools are less hazardous than electric power tools. Grinders and impact tools have air hoses (pipes) which pose tripping or stumbling hazard. Self-storing recoiling air hoses are safe. Speed regulator or governor is necessary to avoid over-speeding the tool.

Impact tools include riveting guns and jackhammers. Air pressure safety valve, automatically closing valve actuated by a trigger located inside the handle (machine can run only when the trigger is depressed) and retaining device that holds the tool in place so that it cannot be fired accidentally from the barrel are necessary.

Air should be filtered and cooled moisture or water should be removed from the tool. Pneumatic tools are of two types - percussive and rotary. In rotary tool either piston and cylinder or rotor vanes are used. Speed regulator is necessary. Pneumatic tools are started and stopped by means of shut off valves and rotary valves. Rotary valves are equipped with a spring returning the rotary handle to its ‘stop’ position as soon as the handle is released. Maximum operating pressure is 6 bar. Additional handle is provided to control back twisting torque when the cutting tool (e.g. drill, reamer) gets jammed.

Effects of noise and vibration cause health hazards. Vibration and jerks cause strain in the joints and disease. ‘White fingers’ or ‘Vasospastic vibration syndrome’ is a disease due to vibration exposure and vascular spasm. 8 to 16 Hz frequency causes the most harmful effects as it generates resonance in hand-arm system. Safe limit of vibration intensity i.e daily exposure is -

60 HZ for 1 hour working and112 HZ for 30 minutes working.

To reduce vibration, damping springs, air cushions and vibration absorbing handles are necessary.

Noise level near the tool should be measured and ear protection should be

given to the operator if necessary. Eye protection is required due to flying chips. Two chippers should work away from each other, back to back, to prevent cuts from flying chips. They should not point a pneumatic hammer at anyone. Neither should it be used to clean dust from clothes due to risk of intestine inflation. Jack hammer handles should have rubber grips to reduce effects of vibration and fatigue. Operators should wear metatarsal - type safety shoes to protect against fall of heavy hammer.

See Chapter-12 for Noise and Vibration.

Hydraulic power tools are hydraulic chain saws and compression devices. A small leak can impose high oil pressure on finger. Therefore, proper pressure hose should be selected. Safety pins are provided to shear at pre-set pressure. Pins should be secured by retainers. Poor quality shear pins, improper design or use of sockets can cause sudden failure and result in flying missiles.

4.2 Selection, Inspection, Maintenance and Repairs :Information and training to select

right tool for the right job is necessary. If a small hole is to be drilled and if it is easily possible by a hand drill, power drill is not necessary. Manual hazards are less serious than the power hazards.

Tool supplier should be given complete information about the job for which a tool is required so that he can recommend the most appropriate tool for that job.

Normally portable power tools are to be used on light or home work. For continuous operation and production service or heavy work, ‘industrial duty’ tools are selected.

Periodic inspections are necessary to find defects and to keep the tool in good working condition. Then it serves the purpose of preventive maintenance. It prevents hazards and costly breakdowns. Defective tools should be tagged and repaired.

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Record of date of inspection, fault noticed and date of repair is necessary. Cause of fault and detail of repair carried out can also be added to such record.

Workers should be trained to inspect tools, identify defects, report and repair. They should be warned not to do makeshift repairs and to do no repair work unless authorised.

For cleaning purpose non flammable and non-toxic solvent should be used.

The following inspection checklist will help in detecting defects in portable tools.

Inspection Checklist

General : Low voltage equipment used in tanks and wet area? Tools well maintained? Motors in good condition? Approved tools used in explosive atmosphere? Tools left where they cannot fall?

Cords : Insulation, plugs and sockets unbroken? Cords protected against trucks & oil? Cords not in aisle?

Grounding : Ground wire fastener in safe condition? 3-wire plug extension cord? Defects or minor shocks reported?

Guarding : Guards used on grinders & saws? Movable guards operate freely? Eye & face protection worn?

4.3 Use of Personal Protective Equipment:

Gloves, loose clothing and jewellery should not be worn by workers using revolving tools such as drills, saws and grinders. The weight of most power tools makes it advisable for users to wear safety shoes (with steel toe) to reduce chances of injury, if the tool falls or drops.

While working at overhead places with power tools, the operator should wear a safety belt and use a good platform or support.

Dust type respirators should be worn on buffing, grinding or sanding jobs which produce harmful dusts.

Ear protection is necessary at high noise levels.

Safety goggles or face shields should be worn for work on grinders, buffing wheels and scratch brushes because the unusual positions in which the wheel operates will cause particles to be thrown off in all directions. For this reason, protective equipment is even more important than it is for work on stationary grinders.

Eye protection equipment (safety goggles or face shields) is a must in all operations where hardened metal tools are struck together, where wood working or other cutting tools are used, where anything is struck by a metal hand tool, or where the cutting action of a tool causes particles to fly. Clothing should be free of oil, solvents or frayed edges to minimise fire hazard from sparks.

Exercise1. Explain, State, Mention or Discuss -

1. Causes and control of tool accidents.

2. Wrong methods to use hand tools.

3. Merits and demerits of centralised tool issue system.

4. Different types of hand tools and factors of their safe use.

5. Types of material handling tools and factors of their safe use.

6. Types of torsion tools and safe methods of their use.

7. Types of portable power tools and their safety aspects.

8. Safety aspects of using electric power tools.

9. Types of pneumatic power tools, their main hazards and control measures.

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10. What type of PPE is required while working on which type of portable power tools?

11. Hazards and control of portable power tools.

12. Main causes and control of hand tools vis-à-vis. power tools.

13. Types of defects in hand tools.14. How hand tools are misused?

What are the methods of right use?

15. A safety programme for control of hand tool accidents.

2. Write Short Notes on -

1. Ergonomic design of hand tools.2. Criteria for careful purchase of

hand tools.3. Safe storage of hand tools.4. Tool boxes.5. Causes of tool failure.6. Maintenance and repairs of

hand tools.7. Dressing of hand tools.8. Handles of hand tools.9. Metal cutting tools.10. Wood cutting tools.11. Correct and wrong use of

screw-driver.12. Non-sparking tools.13. Knife accidents.14. Safe methods to use portable

power tools.15. White finger disease.16. Safe methods of using air-

powered tools.17. Noise and vibration control of

pneumatic tools.18. Hydraulic power tools.19. Inspection checklist for portable

power tools.20. Double insulation.21. Fail safe design of a portable

power tool.

22. Main causes of hand tool injuries and remedial measures for them.

23. Safe practices to be followed in the use of hand tools OR power tools.

24. Spark resistant tools.

3. Explain the difference between –

1. Centralised tool issue system and personal tool issue system.

2. Tempering of tools and safe – ending of tools.

3. Pressing and redressing of hand tools.

4. Metal cutting tools and wood cutting tools.

5. Chisel and File.6. Hack saw and cutter.7. Crowbar and shovel.8. Pliers and pullers.9. Double protection and Dead

man control.10. Shock tools and torsion tools.

4. Comment on the following explaining whether it is true or false –

1. No work is finally possible without hand-held or hand operated tool.

2. It is wrong belief that non-sparking tools are safe.

3. Electric drill should not be used in wet condition.

4. Earthing of portable electric grinder is not necessary.

5. Trained purchase officer is necessary for ordering hand tools or power tools.

Reference and Recommended Readings

1. Accident Prevention Manual for Industrial Operations, NSC, USA.

2. Encyclopaedia of Occupational Health & Safety, ILO, Geneva.

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