Intro to Machine Shop

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Chapter 1

INTRODUCTION TO THE MACHINE SHOP

GENERAL INFORMATION

FORMS, RECORD S, AND REPORTS

Accurate records ar e valuab le. Unit officers are respon siblefor comp letion of forms, records, and reports. DA Pam 738-750 lists records, reports, and au thorized form s that arenorm ally used for insp ection and repair. Properly executedforms auth orize and record rep air or replacement of materiel.The forms, records, and reports document the work required,follow the p rogress of the work w ithin the shops, and ind icate

the status of the material upon completion of repairs.

FIELD REPORT OF ACCIDENTS

The reports necessary to comply with the requirements ofthe Arm y Safety Program are p rescribed in detail in AR 385-40. These reports are required for any accidents involvinginjury or d amage. For a listing of all forms, refer to DA Pam25-30.

Any deficiencies detected in the equ ipment covered hereinshould be immediately reported in accordance with DA Pam738-750. These repor ts w ill be subm itted as an Equipm entImpr ovement Recommend ation on SF 368.

DEFINITIO N OF MACHINE TOOLS

Machine tools are power-driven equipment designed todrill, bore, grind, or cut metal or other material.

LISTING O F MACH INE TOOLS

A complete list of machine tools including specializedmachine tools currently authorized for issue is in Component

List C 3405/ 70-lL.

SPECIALIZED M ACHINE TOO LS

In view of the different design and operating featuresincorporated in specialized m achine tools (cylind er boring

machines, brake reliners, valve seat grind ers. and so forth) byvarious manufacturers, no attempt has been made to includeinformation pertinent to them in this man ual. For completeinform ation on these to ols, see pertine nt TM 9-3400-, TM 95100-, and TM 9-9000-series techn ical manu als covering th especific machines.

RISK-MANAGEMENT

To assure a high degree of safety, no machine -tool is to beused unless the risk management process as outlined below isunderstood and applied by the user and the sup ervisor:

1. Identify the potential hazard (s) that th e machine tool cangenerate.

2. Assess the pr obability and severity ofthe hazard (s) byutilizing the Risk Assessment M atrix in figure 1-1. Riskacceptance d ecision au thority for the r isk levels is as follows:

a. Extremely high - CG, TRADO C; DCG, TRADO C;or the Chief of Staff, TRADOC.

b. High - Major subord inate comm and s, installationcommand ing generals, and school comm andan ts of generaofficer rank.

c. Moderate and low - Delegated to the app ropriatelevel in your unit chain of command.

3. Determine the risk control measures th at will eliminate thehazard(s) or reduce the risk.

4. Implement the risk control measures before and duringoperation of the m achine tool to eliminate th e hazard s or

reduce their risks.

5. Sup ervise and evalu ate the pr ocess. Enforce theestablished standards and risk control measures. Evaluate theeffectiveness of the control measures and adjust/ upd ate themas necessary.

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A.

B.

C.

D .

E.

PROBABILITY

FREQUENT - Individu al soldier/ item - Occurs often inthe career/ equipm ent service life. All soldiers or iteminventory exposed - Continuously experienced duringoperation/ mission.

LIKELY - Individu al soldier/ item - Occurs several timesin career/ equipm ent service life. - All soldiers or item

inventory exposed. - Occur s frequently duringoperator/ mission.

OCCASIONAL - Individual soldier/ item. - Occurssometimes in career/ equip ment service life. All soldiersor item inventory exposed. Occurs sporadically, orseveral times in inventory service or operations/ mission.

REMOTE - Individ ual soldier/ item - Possible to occurin career/ equipm ent service life. All soldiers or iteminventory exposed, Remote chance of occurrence -Expected to occur sometime in inventory service life oroperation/ mission.

UNLIKELY - Individual soldier/ item - Can assume w illnot occur in career/ equipment/ service life. All soldiersor item inventor y exposed. - Possible, but impr obable;occurs only very rarely du ring operation/ mission.

SEVERITY

I. CATASTROPH IC - Death or permanent totaldisability. System loss. Major property damage.

II CRITICAL- Permanen t par tial disability. Temp orarytotal disability in excess of 3 months. Major system damage.Significant property damage.

III. MARGINAL - Minor injury. Lost w orkday accidentwith compensable injury/ illness. Mirror system dam age.Minor property damage.

IV. NEGLIGIBLE - First aid or m inortreatment. Minor system impairment.

RISK LEVELS

supportive medical

EXTREMELY HIGH - Loss of ability to accomplishmission.

HIGH - Significantly degrades mission capabilities in termsof required mission standard s.

MODERATE- Degrades m ission capabilities in term s ofrequired missions standards.

LOW - Little or no impact on accomplishment of mission.

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MACHINE SHOP WORK

SCOPE

Machine shop work is generally understood to include all

cold-metal work by which an operator, using either pow erdriven equipment or hand tools, removes a p ortion of themetal and shapes it to some sp ecified form or size. It does notinclude sheet metal work and coppersmithing.

LAYING OUT WO RK

Laying out is a shop term wh ich m eans to scribe lines,circles, centers, and so forth, up on th e surface of any m aterialto serve as a guide in sh aping th e finished w orkpiece. Thislaying ou t procedure is similar to shop d rawing bu t d iffersfrom it in one importan t respect. The lines on a shop dr awing

in the finished wor kpiece, For tha t reason, all scribed line

should be exactly located and all scriber, divider, and centepoints should be exact and sharp.

SCRIBING LINES ON METAL

The shiny su rface, found on m ost metals, makes it difficuto see the layou t lines.

Layout d ye (Figure 1-2), wh en app lied to th e metal surfacmak es it easier for the layout lines to be seen. Layout d ye usually blue and offers an excellent contrast between the metand the layout lines.

are used for reference purp oses only and are not measured or

transferred. In layout w ork, even a slight error in scribing a Before applying layout dye, ensure that all grease and oline or center may result in a corresponding or greater error has been cleaned from the work su rface. Otherw ise the dy

will not adhere properly.

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COMM ON LAYOUT TOO LS

Scriber

To obtain an accurate layout, fine lines must be scribed inmetal. A scriber (Figure 1-3) is the layout tool that is used

prod uce these lines. The point is mad e of hardened steel is kept chain by honing on an oilstone.

Divider

When laying out circles, arcs, and radii, it is best to use thevid er (Figur e 1-4). The legs of the divider mu st be of theme length and be kept sharp. The divider cart be used to

lay out an d measure distances (Figure 1-5). To set the d ividerto the correct length, place one point on an inch mark of asteel rule and open the d ivider until the other leg matches thecorrect measure-merit required (Figure 1-6).

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Trammel

When scribing circles, arcs, and ra dii that are too large to beprodu ced with the d ivider, a tramm el should be used (Figure1-7). The tram mel is made of thr ee main p arts: the beam, twosliding heads with scriber points, and an adjusting screw thatis attached to one of the heads. The trammel can be made toscribe larger distances with the u se of extension rods. Thislayout tool is set in the same manner as the divider.

Hermaphrodite Caliper

The herm aphr odite caliper (Figure 1-8) is a tool used to layout lines that are parallel with the edges of the workpiece(Figure 1-9). It can also be used to locate the center ofcylind rical shaped work places (Figure 1-10).

Surface Gage

A surface gage (Figur e 1-11) is used for man y pu rposes, is most often used for layout w ork. The gage can be usedscribe layout lines at any given distance parallel to the wsurface (Figure 1-12).


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The spindle may be adjusted to any position with respect tothe base and tightened in place with the spindle nut (Figure 1-11). The rocker adjusting screw provides for finer adjustment

of the spindle by pivoting the spindle rocker bracket. Thescriber can be positioned at any h eight and in an y desireddirection on the sp indle by ad justing the scriber. A surfaceplate and combination square (Figure l-13) are needed to setthe surface gage to the correct dimension.

Surface Plate

A surface plate (Figure l-14) provides a true, smooth, planesurface. It is used in conjunction with surface and height gagesas a level base on w hich the gages an d the w orkpiece areplaced to obtain accurate measurements. These plates are

mad e of semi-steel or granite and should n ever be used forany job that would scratch or nick the surface.

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Vernier Height Gage

The vernier h eight gage (Figure 1-15) is a caliper with aspecial foot block to ad apt it for u se on a su rface plate. Heightgages are available in several sizes: the m ost common are the

10, 18, and 24 inch gages in English measure and the 25 and46 cm gages in m etric measure. Like the vernier caliper, theseheight gages are g radu ated in d ivisions of 0.025 inch an d avernier scale of 25 units for reading measurements tothou sand ths of an inch. Always be sure the bottom of the footblock (Figure 1-15) is clean an d free from bu rrs.

upright beam.

Figure 1-16 shows the height gage with a tungsten carbidemarker. This marker is used to lay out lines on glass, hardenedsteel. or other hard materials.

Figure 1-17 illustrates the use of an offset scriber with theheight gage. This scriber reaches below th e gage base. Do n oattempt to adjust the sliding jaw while it is clamped to the

Combination Square Set

The combination square set (Figure 1-18) is used for nu mb er of layout op erations. The set consists of a blad(graduated rule), square head, protractor, and center head.

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Blade

The blade is designed to allow the different heads to slidelong the blade and be clamped at any desired location. Theroove in the blade is concave to eliminate dirt buildup anderm it a free and easy slide for the h eads. By remov ing all theeads, the blade may be used alone as a rule.

Square Head

The square head is designed w ith a 45 and 90 edge, whichmakes it possible to be used as a try squ are and miter square.By extending the blade below the square, it can be used as aepth rule. The square head can also be used as a level.

Protractor H ead

The protractor head is equipped w ith a revolving turr etrad uated in degrees from 0 to 180 or to 90 in either d irection.

t is used to measure or lay out angles to an accuracy of 1.

Center Head

The center head, when inserted on the blade, is used toocate and lay out the center of cylindrical workplaces.

Bevel Protractor

The bevel protractor (Figure 1-19) consists of an adjustablelade w ith a grad uated dial. The blade is usu ally 12 inches

ong and 1/ 16 inch thick. The dial is graduated in degreeshrough a complete circle of 360. The most common use forhis tool is laying ou t p recision a ngles. The vernier scale issed for accurate angle adjustmen ts and is accurate to 5

minutes or 1/ 12.

STEPS IN M AKING A LAYOUT

Planning before beginning any layou t is one of the mostimportant steps. Each job may require different layout toolsdep ending on the accuracy needed; how ever, there are certain

procedures which should be followed in any layout. Figure 1-20 shows a typical layout.

Study the shop drawing or blueprint carefully before youcut off the stock. Allow enough material to square theends if required.

Remove all oil and gr ease from the w ork surface andapply layout dye.

Locate and scribe a reference or base line. All the othermeasurements should be made from this. If the workpiecealready h as one tru e edge, it can be used in p lace of the

reference line.

Using the b ase line as a reference line, locate and scribeall center lines for each circle, rad ius, or ar c.

Mark th e points w here the center lines intersect using asharp prick punch.

Scribe all circles, radii, and arcs using the divider ortrammel.

Using the correct type protractor, locate and scribe allstraight and angular lines.

Scribe all lines for internal openings.

All layout lines shou ld be clean, sharp , and fine. Reapp lylayout d ye to all messy, wide, or incorrect lines andrescribe.

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JIGS AN D FIXTURES

The primary purpose of jigs and fixtures is to align theThe layout tools mentioned in this section are only the most and hold the workpiece properly during machining. A fi

commonly used . For more information on the use and care of is a device which holds the w ork w hile cutting tools athese tools and other layout and measuring tools, refer to TM operation . It differs from a jig in that it has n o guid9-243.

special arrangements for guiding tools. A jig is also a fifor locating or holding the work and guiding the cuttingin operations such as d rilling, reaming, coun terboringcountersinking.


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Jigs and fixtur es can gr eatly redu ce the cost ofmanufacturing large quantities of parts. Their use is also anadv antage wh en the interchangeability and a ccuracy of thefinished products are important. They also can be used in lowor limited production jobs if extreme accuracy must bemaintained. One of their greatest advantages is that relativelyun skilled labor can accomp lish th e job u sing these special

tools.

MECHANICAL DRAWINGS ANDBLUEPRINTS

Mechanical Drawin gs

A m echanical drawing, mad e with special instruments an dtools, gives a true rep resentation of an object to be mad e,including its shape, size, description, material to be used, andmethod of manufacture.

BlueprintsA blueprint is an exact duplicate of a mechanical drawing.

These are the m ost econom ical and satisfactory w orkingdrawings in u se. They do not soil easily and arecomparatively easy to read. Blueprint paper is a good grade ofwhite paper coated with a chemical solution. making itgreenish yellow. A blueprint is made by placing a tracing of amechanical draw ing on a sheet of blueprint pap er andexposing it to light. During exposure. the light penetrateswh ere there are no lines or printing on the tracing but doesnot pen etrate where ther e are lines or printing. The print isthen washed in water. which changes the exposed chemical to

a dar k blue and wash es the chemical off where lines andprinting pr evented exposure. In other w ords. the processleaves white lines on d ark blue background.

Working From D rawings

Detail prints usually show only the individual part or piecehat mu st be produced. They show two or more orthographicstraight-on) views of the object. and in special cases. they

may show an isometric projection. without dimension lines,near the u pp er right corner. An isometric projection showshow the p art will look when m ade. Each draw ing or blueprintcarries a number. located in the upper left-hand corner and in

he title box in the low er right-hand corner of the pr int. Theitle box also shows the part name, the scale used, the patternnumber. the material required. the assembly or subassemblyprint number to which the part belongs. the job order number,he quantity and date of the order. and the names or initials ofhe persons w ho drew. checked. and approved the drawingsFigure 1-20). Accurate and satisfactory fabrication of a partescribed on a drawing depends upon the following:

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Correctly reading the drawing and closely observing alldata on the drawing.

Selecting the correct tools and instruments for laying outthe job.

Use the baseline or reference line method of locating the

dimensional points during layout. thereby avoidingcumulative errors.

Strictly observing tolerances and allowances.

Accurate gaging and measuring of work throughout thefabricating process.

Giving due consideration when measuring for expansionof the workpiece by heat generated by the cuttingoperations. This is especially importan t wh en checkingdimensions during operations, if work is being machinedto close tolerances.

Limits of Accuracy

Work must be performed within the limits of accuracyspecified on the drawing. A clear understanding of toleranceand allowance will help you avoid making small, butpotentially large errors. These terms m ay seem closely relatedbut each has a very precise meaning and application. Theparagraphs below p oint out the m eanings of these terms andthe importance of observing the distinctions between them.

Tolerance

Working to th e absolute or exact basic dimension isimpractical and unnecessary in most instances: therefore, thedesigner calculates. in ad dition to the ba sic dimensions, anallowable variation. The amount of variation. or limit of errorpermissible is indicated on the drawing as plus or minus (+ )a given am ount. such as + 0.005 or + 1/ 64. The differencebetween the allowable minimum and the allowable maximumdimension is tolerance. When tolerances are not actuallyspecified on a d raw ing, fairly concrete assump tions can bemade concerning the accuracy expected. by using thefollowing principles, For dimensions which end in a fractionof an inch. such as 1/ 8, 1/ 16, 1/ 32, 1/ 64. consider the

expected accuracy to be to the nearest 1/ 64 inch. When thedim ension is given in d ecimal form the following ap plies: If adim ension is given a s 2.000 inches, the accura cy expected is+0.005 inch: or if the dimension is given as 2.00 inches, theaccuracy expected is +0,010 inch. The +0.005 is called inshop terms, "plus or minus five thousandths of an inch. The+ 0.010 is called p lus or m inus ten t housan dth s of an inch.


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Allowance

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Precautions

Allowance is an intentional d ifference in d imensions ofmating p arts to pr ovide the d esired fit. A clearance allowancepermits movement between mating parts when assembled. For

example, when a hole w ith a 0.250-inch d iameter is fitted w itha shaft th at has a 0.245-inch d iameter, the clearance allowanceis 0.005 inch. An in terference allow ance is the op posite of aclearance allowance. The d ifference in dim ensions in th is caseprovides a tight fit. Force is required when assembling partswh ich h ave an interference allowan ce. If a shaft w ith a 0.251-inch diameter is fitted in the hole identified in the precedingexample, the difference between the dimensions will give aninterference allowance of 0.001 inch. As the shaft is larger

Be sure you h ave the correct print for the part to be m adrepaired. You w ant the p rint wh ich has not only the cortitle, but also the correct assembly nu mb er. Never ta

measurement with a rule directly from the print becausetracing from which the print was made may not have bcopied from the original drawing perfectly and may conscaling errors. Also, paper stretches and shrinks with chain atmosp heric cond itions. Dimensions mu st be taken from the figures shown on the dimension lines. Be vcareful in han dling all blueprints and w orking draw iWhen they are not in use, place them on a shelf, in a cabor in a dr awer. Return them to the blueprint file as soon as

than the hole, force is necessary to assemble the parts. job is done. Blueprints and working d rawings are alwvaluable and often irreplaceable. Make it a point nevemutilate, destroy, or lose a blueprint.


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GENERAL SHO P SAFETY

All tools are dan gerous if used im prop erly or carelessly.Working safely is the first thing the user or operator shouldlearn because the safe way is the correct way. A p erson

learning to operate machine tools must first learn the safetyregulations and precau tions for each tool or ma chine. Mostaccidents are caused by not following prescribed procedures.Develop safe work habits rather than suffer the consequencesof an accident.

Most of the safety practices mentioned in this section aregeneral in n ature. Safety p recautions for specific tools andmachines are described in detail in the chapters along with thedescription of the equipm ent. Stud y these carefully and be onthe alert to apply them.

EYE PROTECTION

Using eye protection in the m achine shop is the m ostimportan t safety rule of all. Metal chips an d shavings can flyat great speeds and distances and cause serious eye injury.Safety glasses must be worn when working w ith hand cuttingtools, since most han dcutting tools are mad e of hardened steeland can break or shatter when used improperly.

There are m any different typ es of safety glasses available inthe sup ply system; how ever, the ones that offer the bestprotection are the safety glasses w ith side shields. Safetygoggles should be wor n over prescription glasses. For specificinformation abou t eye protection, contact the Occupationa lHealth Clinic or refer to TB MED 586.

HAZARDO US NOISE PROTECTION

Noise hazards are very common in the machine shop. Highintensity noise can cause p erman ent loss of hearing. Althou ghnoise hazards cannot always be eliminated, hearing loss isavoidable with ear m uffs, ear plugs, or both. These areavailable through the local supply system or from theOccup ational Health Clinic. Ear p lugs m ust be prop erly fittedby qu alified p ersonnel. For specific information on h earingprotection, refer to TB MED 501.

FOOT PROTECTION

The floor in a machine shop is often covered w ith razor-sharp m etal chips, and heavy stock may be dropp ed on thefeet. Therefore, safety shoes or a solid leather shoe m ust beworn at all times. Safety shoes are available in the supply

system. These have a steeldesigned to resist impact.instep guard.

plate located over the toe and areSome safety shoes also have an

GRINDING DUST AND H AZARDOUS FUMES

Grinding d ust from abrasive wheels is made u p of extremelyfine p articles of the m etal and th e wh eel. Some grindingmachines are equipped with a vacuum dust collector. Whenoperating a grinder without a vacuum, wear an approvedrespirator to avoid inhaling the dust. Whenever possible, usecoolant w hen grind ing. This will aid in du st control. Grindingdust can be very dangerous to your health, especiallyberyllium or parts u sed in nu clear systems. These materialsrequire careful control of grinding dust.

Metals such as zinc give off toxic fum es wh en heated abovetheir boiling point. Inhaling these fum es may cause tempora rysickness, or death. The fum es produ ced from lead andmercury are very harmful, as their effect is cumulative in thebody and can cause irreversible damage. When unsure of thematerials being m achined, it is adv isable to wear a respirator.For more specific information on r espirator safety, refer to TBMED 502.

PROP ER LIFTIN G PRO CEDURES

Using improper lifting procedures may result in a permanent

back injury. Back injury can be avoided if the correct liftingprocedures are followed. When lifting heavy or large objects,get some assistance or use a hoist or forklift.

Objects within your ability can be lifted safely as long as thefollowing procedures are followed:

Keep your back straight.

Squat down, bending at the knees.

Use the leg muscles to do the work and lift slowly. Donot bend over the load as this will put excessive strain on

your spine.Carry th e object wh ere it is comfortable, and pay closeattention to where you are walking and objects aroundyou.

When placing the object back on the floor, use the sameprocedures as when it was lifted.

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ELECTRICAL SAFETY

Exposu re to electrical hazard w ill be minim al unless theoperator becomes involved w ith machine repair. The machineoperator is mostly concerned with the on and off switch on themachine tool. However, if adjustments or repairs must be

mad e, the pow er source should be d isconnected. If themachine tool is wired perm anently, the circuit breaker shouldbe switched off and tagged w ith an approp riate w arningstatement. Most often the power source will not bedisconnected for routine adjustment such as changing machinespeeds. How ever, if a speed change involves a belt change,make sure that no other person is likely to turn on the machinewhile the operators hands are in contact with belts andpulleys.

SAFETY RULES FOR M ACH INE TOO LS

Since different cutting tools and machining procedures areused on various m achine tools, the safety precautions for eachm ay vary. The follow ing are genera l safety ru les for anymachine tool:

Gears, pulleys, belts, couplings, ends of shafts havingkeyways, and other revolving or reciprocating partsshould be guard ed to a height of 6 feet above the floor.The guards shou ld be rem oved only for repairing oradjusting the m achine and mu st be replaced beforeoperating it.

Safety setscrews shou ld be used in collars and on all

revolving or reciprocating members of the machine toolor its equipment.

Do not op erate any machine tool without p roper lighting.

Never attempt to operate any machine tool until you fullyund erstand h ow it works and know how to stop it quickly.

Never w ear loose or torn clothing and secure long hair,since these items can become caught in revolvingmachine parts. Ties should be removed and shirt sleevesshould be rolled up above the elbow.

Gloves should never be w orn w hen operating machineryexcept when absolutely necessary.

Alw ays stop the m achine before cleaning it or takingmeasurements of the workpiece.

Do not lubr icate a m achine while it is in motion. Injury the operator and d amage to the machine may result frothis practice.

Never remove metal chips, turnings, or shavings wiyour hands; they may cause a serious cut. If the shavinare long, stop the machine and break them with pliers orbent rod, and then brush chips off the machine. Remocast-iron chips, wh ich break into sm all pieces, withbrush. Never wipe away chips when the machine operating.

Always w ear safety glasses or goggles while operatimachine tools. Also, wear resp iratory protectionoperation creates hazardous dust. All persons in the arwh ere power tools are being operated should also wesafety eye protection and respirators as needed.

Know where tire extinguishers are located in the shoarea and how to use them.

Never wear jewelry while working around machine toolRings, watches, or bracelets maybe caugh t in a revolvinpart which could result in the hand being pulled into thmachine.

Avoid horseplay. Tools are very sharp and machines amad e of hard steel. An accidenta l slip or fall may cau seserious injury.

Never use compressed air without a safety nozzle to cleamachines or clothing. It will blow sharp , dangerou s metchips a long distance.

Keep the floor arou nd machines free of tools, stock, ogrease, and m etal chips. Tripping over m etal on the flooespecially round bars, can cause dan gerous falls. Wipe uall oil, grease, and cutting fluid sp ills on th e floor as sooas possible to prevent a fall. Metal chips are v ery sharand can easily become em bedd ed in the soles of shoemaking them very slipp ery, especially when w alking onconcrete floor.

Never p lace tools or other m aterials on the machine tablCluttering up a machine w ith tools or materials createunsafe working conditions. Use a bench or table near thmachine for this purpose.

Always use a rag w hen hand ling sharp cutters such amilling cutters and end mills.

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Do not expose power tools to rain or use in damp or wet Remove adjusting keys and wrenches. Form a habit oflocations. checking to see that keys and w renches are removed from

tools before turning them on.Always secure the workpiece. Use clamps or a vise. It issafer than u sing your hand s, and it frees both hand s to Do not operate any machine tool while under the

operate the tool influence of drugs, alcohol, or any medication that couldcause drowsiness.Do not abu se electrical cords. Nev er carry a tool by itscord or ya nk it to d isconnect it from a receptacle. Keepelectrical cords away from heat, oil, and sharp edges.Have dam aged or w orn pow er cords and strain relieversrepaired or replaced immediately.

SAFETY COLOR COD E MARKIN GS AND SIG NS

USE OF PAINT

All maintenance shops an d w ork areas should be markedwith the correct colors to identify hazards, exits, safewalkways, and first-aid stations. It is acceptable to usematerial other than paint, such as d ecals and tapes, in theppropriate, similar colors. Listed below are the main colorsuthorized for use in maintenance shops.

Red color markings should be used to identify the followingquipment or locations:

Fire alarm boxes (pu ll boxes).

Fire blanket boxes.

Fire extinguishing containers.

Fire extinguishers, unless painting is unnecessary. Forlarge areas and w hen th e extinguisher is not readilyvisible to the area occup ants, use red on the hou sing wallor support above the extinguisher to show its location.

Fire hose locations.

Fire pumps.

Fire sirens.

Sprinkler piping.

Fire buckets.

Fire reporting telephone stations.

Store all idle tools in a safe, dry place.

Provide visitors to the work area requ ired personn elprotection equipment.

An exception may be made to comply with local laws orwhen current facilities provide green exit signs.

Emergency stop buttons for electrical machinery.

Emergency stop bars on hazardous machines.

Yellow color markings should be used to identify thefollowing equipment or locations:

Industrial areas where particular caution is needed, suchas handrails, guardrails, bottom edge of overhead doors,or top and bottom treads of stairways.

Fire hydrant barrels.

Caution signs.

Piping systems containing flammable material.

Waste containers for highly combustible material.

A hazardous area or a safe aisle within a hazardous area.

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Lower pulley blocks and cranes.

Coverings and guards for guy wires.

Pillars, posts, or columns that are p hysical or shophazards.

Fixtures suspended from ceilings or walls that extend intonormal operating areas.

Corner markings for storage piles.

Exposed and unguarded edges of platform s, pits, andwells.

Green color markings normally on a white color backgroundshould be used for the following equipment or locations:

First-aid equipment.

First-aid dispensaries.

Stretchers.

Safety starting buttons on machinery.

Safety instruction signs.

Black and white are the basic colors for designatinghousekeeping and interior traffic markings. The following areexamp les of where solid w hite, solid black, single-colorstriping, alternate stripes of black and white, or black andwhite squares will be used.

Locations and width of aisles in nonhazardous areas.

Dead ends of aisles or passageways.

Directional signs.

Locations of refuse cans.

White corners of rooms or passageways.

Clear floor area around first-aid, fire-fighting, and theiremergency equipment.

Blue color ma rkings are u sed on th e outside of switch boxeselectrical controls that are the starting point or power sourcefor hazardous electrical machinery or equipment.

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Orange markings are used to designate dangerous partmachines or energized equipm ent, includ ing electriconduits, which may cut, crush, shock, or injure.

CATEGORIES OF SIGNS

Signs are placed in categories according to their purpoUse the examp les in the following pa ragrap hs as guides wchoosing the correct sign d esign to disp lay a m essageoverseas commands, the use of International Standard SafSigns is encouraged and authorized.

WORDING O F SIGNS

Ensure that the wording of any sign-

Is concise and easy to read.

Contains enough information to be easily understood.Is designed for the m essage to be carried in a p ictwhen app ropriate.

Is a positive rather than a negative statement whappropriate.

Is bilingual with the second language common to local personnel when appropriate.

SIGN INSPECTION AND MAINTENANCE

Signs should be inspected regularly and m aintained in gocond ition. They shou ld be kept clean, w ell illum inated , alegible. Replace or repair d amaged or broken signs. All siwill be designed with round ed or blunt corners and withsharp projections. Put the end s or head s of bolts or otfastening devices where they will not cause a hazard.

SELECTION OF SIGN SIZE

When choosing a sign, consider dimensions that will pereconomical use of standar d size material. Base the size of sign on the following:

Location at which the sign will be placed.

Character of the hazard involved.

Purpose of the sign.

Distance from which the sign should be legible.

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REQUIRED SIGN COLORS

All signs require a predominant color based on the signsrpose. Below are the five types of signs and theirdominant color.

Danger signs: RED.

Caution signs: YELLOW.

Safety instruction signs: GREEN.

Directional signs: BLACK.

Informational signs: A variety of colors may be used,except for red, yellow, or magenta (purple).

DANGER SIGNS

Danger signs should only be used when immediate hazardsts. There will be no variations in the type or design ofns posted to war n of specific danger. All personn el will betructed that danger signs indicate immediate danger and special precautions are necessary.

CAUTION SIGNS

aution signs should be used only to warn against potentialards or to caution against unsafe practices. All personnell be instructed th at a caution sign indicates a possible

ard against which proper precautions will be taken.

DIRECTIONAL SIGN S

Directional signs should be used in sufficient numbers toicate the w ay to stairwa ys, fire escapes, exits, and other

ations.

Many other safety media are available for use in militaryntenance shops.

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Documents

Intro to Machine Shop