DJJ1043WORKSHOP TECHNOLOGY

CHAPTER 1

HAND TOOLS

Prepared: MFM 1

THE BASIC RULES1. Never work alone

- At least two adults must be in the workshop when power tools are being used.

2. Never work when you are impaired.

- This includes when you are too tired, stressed or hurried to work carefully.

3. If you cannot do a job safety in this workshop, don’t do it.

- There are limits to what we can build here.

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4. Always wear closed-toe shoes in the workshop.

- tools, chips and fixtures are sharp and often hot. Shoes will help protect your feet from injury. Leather shoes are preferred when welding.

5. Eye protection is essential. Always wear safety glasses when working or cleaning tools.

- Prescription glasses sold with plastic lenses meet ANSI Standard Z87.1 for safety.

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6. Remove or secure anything that might get caught in moving machinery.

- rings, necklaces, long hair and loose clothes that get caught in tools can drag you along.

7. Keep your hands away from sharp tools.

- Make sure that nothing that you do will cause you to be cut.

8. Dust, chemicals and smoke can be dangerous work in well ventilated areas, minimize contamination and us appropriate protective equipment.Prepared: MFM 4

- The safety equipment cabinet is on the patio.

9. Clean up after yourself.

- Before you leave the workshop each day all tools must be returned to the toolbox, the machine cleaned and wiped down and the floor swept. Leave 10-15 minutes for cleanup.

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HAND TOOLS1. SCRIBER

- Used in metalworking to mark lines on work pieces.

- They are used by drawing the point over the surface of the work piece to leave a shallow scratch on its surface

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2. CENTRE PUNCH

- Used to position a dill for drilling.

- Has sides a 90° angle to one another

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3. PRICK PUNCH

- A prick punch is primarily used for the purposes of layout.

- The same general shape as the Centre punch and usually with a ground point angle of 60°.

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4. DIVIDER

- Used for scribing circle and curves.

- Also use for stepping of distances.

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5. SURFACE PLATE

- Used for accurate marking lay out, checking of surfaces for flat and checking parts for alignment height.

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6. VEE BLOCK

- The v-block and clamp set is used to hold and drill round stock.

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7. L SQUARE

- The square refers to the tools primary use of measuring the accuracy of a right angle 90°.

- To try a surface is to check its straightness or correspondence to an adjoining surface.

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8. STEEL RULER

- Used to take measure, check surface level and help scratch straight line.

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9. COMBINATION SET SQUARE

- A combination square is a tool used for multiple purposes in metalworking.

- The square refers to the primary use of the tool :measuring the accuracy of a right angle 90°.

- A combination square consisting of the ruler, 45° holder, protractor and center square.

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10. SURFACE HEIGHT GAUGE / SCRIBER BLOCK

- A scriber block is used to layout lines at a set height from the base.

- Thus its second name surface height gauge or just “surface gauge”.

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11. HACK SAW

- A hack saw is a fine-tooth saw with a blade under tension in a frame.

- Used for cutting materials such as metal or bone. Some have pistol grips which keep the hacksaw firm and easy to grip.

- Large, power hacksaw are sometimes used to replace a band saw in machine shops.

Prepared: MFM 16

HACK SAW BLADE

PRECAUTIONS / IN USE OF A HACK SAW

1. Choose a blade of the right type.

2. Correctly tension blade.

3. Ensure that the work is secured rigidly.

4. Do not twist blade and exert too mush pressure, a this will break the blade

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12. FILE

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- A file is a metalworking tool used to cut fine a mounts of material from a work piece.

- Hand files are used in the workshop to smooth rough edges.

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PROCEDURE TO FILING

Purpose of Filing

1. Smooth Strokes 3. Oblique Strokes

2. Hard Strokes 4. Pull Stroke

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PINNING

- Pinning refers to the clogging of the file teeth with pins, which are material shavings.

- These pins cause the file to lose its cutting ability and can scratch the work piece.

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SAFETY PROCEDURES OF FILING

1. Don’t wipe off chips with bare hands.

2. Use files with crackles file handles only.

3. Bore and enlarge new file handle according to the tang and then fix them by gentle hammer blows.

4. Hardened parts roust not be filed.

5. Don’t stack files one above the other, protect them from falling down.

6. Clean files regularly with file brush and latten brass.

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FILES ARE SELECTED DEPENDING ON :-

1. The shape of the face or edge to be filed.

2. The hardness of the material to be filed.

3. The size of the face to be filed.

4. The amount of filing and the surface finish,

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STANDING POSITION AND GUIDING OF THE FILE

- Before beginning to file make sure that the vise has the correct height and the work piece is firmly clamped.

PROCEDURE

1. The weight of the body is resting on one leg, the other leg is always straightened, both feet have to be firmly on the ground.

Prepared: MFM 24

2. The file is moved with the arms only, not with the upper part of the body, the upper part of the body must not swing.

3. The file is pressed onto the work piece when pushing the file forward only, it is pulled back without pressure.

4. The file is to be guided so that the movement is always horizontal.

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13. HAMMER

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- A hammer is a tool meant to deliver an impact to an object.

- The most common uses are for driving nails, fitting parts, forging metal and breaking up objects.

- Hammers are often designed for a specific purpose and vary widely in their shape and structure.

- The usual features are a handle and a head, with most of the weight in the head.

Prepared: MFM 27

PARTS OF BALL PEEN HAMMER

TYPES OF HAMMER

1. Ball Peen

- Normally used in machine workshop, the peen in this case is rounded and is usually used for shaping metal and closing rivets.

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2. Cross and Straight Peen

- Used for shaping metal, the peen can be at right angles to the handle or parallel with it.

- The most useful domestically is the cross peen, where the peen can be used for starting panel pins and tacks.

- Handles are normally wood.

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3. Claw Hammer

- The most popular hammer foe general work, available with a wooden glass-fibre or steel handle.

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14. CHISEL

- This is used for metal cutting and chipping.

- It is made of carbon steel.

- Its shank is rectangular, hexagonal or octagonal in cross section.

- The length of a flat chisel varies from 100 mm to 400 mm and the width of the cutting edge varies from 16 mm too 32 mm.

Prepared: MFM 31

COLD CHISEL

- A cold chisel is a tool made of tempered steel used for cutting ‘cold’ metals, meaning that they are not used in conjunction with heating torches.

- Cold chisels are used to remove waste metal when a very smooth finish is not required or when the work cannot be done with other tools, such as a hacksaw, file, bench shears or power tools.

Prepared: MFM 32

HOT CHISEL

- A hot chisel is used to cut metal that has been heated in a forge to soften the metal.

- One type of hot chisel is the “hardy chisel”, which is used in an anvil hardy hole with the cutting edge oriented up.

- The hammer drives the work piece into the chisel, which allows it to be snapped off with a pair of tongs.

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MUSHROM HEAD CHISEL

- When the head of the chisel has been stuck and beaten so that the edge of the head has rolled out and flattened.

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15. TAP AND DIES

- Tapping is the operation of cutting an internal thread by means of a cutting tool known as a tap.

- When tapping by hand, straight-flute hand taps are used.

- These are made from hardened high-speed steel and are supplied in sets of three.

- The three taps differ in the length of chamfer at the point, known as the lead.

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- The one with the longest lead is referred to as the taper or first tap, the next as the second or intermediate tap and the third, which has a very short lead, as the bottoming or plug tap.

Set of taps Tap wrenches

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- Dies are used to cut external threads and are available in sizes up to approximately 36 mm thread diameter.

- The common type, for use by hand, is the circular split die, made from high-speed steel hardened and tempered and split at one side to enable small adjustments of size to be made.

Prepared: MFM 37

Circular split die Die holder

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VERNIER CALIPERS

-Vernier calipers are precision tools used

to make accurate measurements to within

0.001 in or 0.02 mm, depending on

whether they are inch or metric vernier

calipers.

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VERNIER CALIPERS

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PARTS OF A VERNIER CALIPER

1. Outside jaws: used to measure external diameter or width of an object

2. Inside jaws: used to measure internal diameter of an object

3. Depth probe: used to measure depths an object or a hole

4. Main scale: gives measurements of up to one decimal place(in cm).

5. Main scale: gives measurements in fraction(in inch)

Prepared: MFM 41

6. Vernier gives measurements up to two

decimal places(in cm)

7. Vernier gives measurements in

fraction(in inch)

8. Retainer: used to block movable part to

allow the easy transferring a

measurement

Prepared: MFM 42

HOW TO USE A VERNIER

CALIPER

- Preparation to take the measurement,

loosen the locking screw and move the

slider to check if the vernier scale works

properly.

- Before measuring, do make sure the

caliper reads “0” when fully closed.

- If the reading is not “0”, adjust the caliper’s

jaws until you get a “0” reading.

Prepared: MFM 43

- Clean the measuring surfaces of both

vernier caliper and the object, then you

can take the measurement.

- Close the jaws lightly on the item which

you want to measure.

- If you are measuring something round, be

sure the axis of the part is perpendicular to

the caliper.

- Namely, make sure you are measuring the

full diameter.

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- An ordinary caliper has jaws you can place

around an object, and on the other side

jaws made to fit inside an object.

- These secondary jaws are for measuring

the inside diameter of an object.

- Also, a stiff bar extends from the caliper as

you open it that can be used to measure

depth.

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HOW TO READ A VERNIER

CALIPER

1) Read the centimeter mark on the fixed

scale to the left of the 0-mark on the

vernier scale. (10mm on the fixed caliper)

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2) Find the millimeter mark on the fixed scale

that is just to the left of the 0-mark on the

vernier scale. (6mm on the fixed caliper)

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3) Look along the ten marks on the vernier

scale and the millimeter marks on the

adjacent fixed scale, until you find the two

that most nearly line up. (0.25mm on the

vernier scale)

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4) To get the correct reading, simply add this

found digit to your previous reading. (10mm + 6mm + 0.25mm= 16.25 mm)

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REVIEW QUESTIONS

Read the following metric caliper setting :-

a)

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b)

c)

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d)

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TYPES OF VERNIER CALIPER

1. DIGITAL CALIPER

- A refinement now popular is the replacement of the analog dial with an electronic digital display on which the reading is displayed.

Prepared: MFM 53

- All provide for zeroing the display at any

point along the slide, allowing the same

sort of differential measurements as with

the dial caliper but without the need to

read numbers that may be upside down.

- Digital calipers typically do not have the

beam structure of a dial or vernier caliper

and therefore do not have the repeatability

or accuracy to an amateur user.

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2. VERNIER HEIGHT GAUGE

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- A vernier height gauge is a height gauge

with the additional refinement of a vernier

scale for greater accuracy in reading or

setting the tool.

- These measuring tools are used in

metalworking or metrology to either set or

measure vertical distances; the pointer is

sharpened to allow it to act as a scriber

and assist in marking out work pieces.

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3. VERNIER DEPTH GAGES

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- These measuring tools are designed to

measure the depth of holes,

recesses,step, and slots.

- Basic part of a vernier depth gage include

the base or anvil with the vernier scale and

the fine adjustment screw.

- Also shown is the graduated beam or bar

that contains the true scale.

- To make accurate measurements the

reference surface must be flat and free

from nicks and burrs.

Prepared: MFM 58

- The base should be held firmly against

the reference surface while the beam is

brought in contact with the surface being

measured.

- The measuring pressure should

approximately equal the pressure axerted

when making a light dot on a piece of

paper with a pencil.

- On the vernier depth gage ,dimensions are

read in the same manner as on a vernier

caliper.

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MICROMETER

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- A micrometer, sometimes known as a micrometer screw gauge, is a device used widely in mechanical engineering and machining for precisely measuring, along with other metrological instruments such as dial calipers and vernier calipers.

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PARTS OF MICROMETER

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1. Frame

- The C-shaped body that holds the anvil and barrel in constant relation to each other. It is thick because it needs to minimize flexion, expansion, and contraction, which would distort the measurement.

- The frame is heavy and consequently has a high thermal mass, to prevent substantial heating up by the holding hand/fingers.

Prepared: MFM 63

2. Anvil

- The shiny part that the spindle moves toward, and that the sample rests against.

3. Sleeve / barrel / stock

- The stationary round part with the linear scale on it. Sometimes vernier markings.

4. Lock nut / lock-ring / thimble lock

- The knurled part (or lever) that one can tighten to hold the spindle stationary, such as when momentarily holding a measurement.

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5. Screw

- (not seen) The heart of the micrometer, as explained under "Operating principles". It is inside the barrel. (No wonder that the usual name for the device in German is Messschraube, literally "measuring screw".)

6. Spindle

- The shiny cylindrical part that the thimble causes to move toward the anvil.

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7. Thimble

- The part that one's thumb turns. Graduated markings.

8. Ratchet stop

- (not shown in illustration) Device on end of handle that limits applied pressure by slipping at a calibrated torque.

Prepared: MFM 66

READING MICROMETER INCH

SYSTEM

- The spindle of an inch-system micrometer has 40 threads per inch, so that one turn moves the spindle axially 0.025 inch (1 ÷ 40 = 0.025), equal to the distance between two graduations on the frame.

- The 25 graduations on the thimble allow the 0.025 inch to be further divided, so that turning the thimble through one division moves the spindle axially 0.001 inch (0.025 ÷25 = 0.001).

Prepared: MFM 67

1. Note the last number showing on the

sleeve. Multiply that number by 0.100.

2. Note the number of small lines visible to

the right of the last number shown.

Multiply that number by 0.025.

3. Note the number of divisions on the

thimble from zero to the line that

coincides with the index line on the

sleeve. Multiply that number by 0.001.

Prepared: MFM 68

- #2 is shown on the sleeve 2×0.100=0.200

- Three lines are visible past 3×0.025=0.75

the number

- #13 line on thimble 13×0.001=0.013

coincides with the index line

- Total reading =0.288 inPrepared: MFM 69

READING MICROMETER METRIC

SYSTEM- The spindle of an ordinary metric

micrometer has 2 threads per millimetre, and thus one complete revolution moves the spindle through a distance of 0.5 millimetre.

- The longitudinal line on the frame is graduated with 1 millimetre divisions and 0.5 millimetre subdivisions.

- The thimble has 50 graduations, each being 0.01 millimetre (one-hundredth of a millimetre).

Prepared: MFM 70

1. Note the number of the last main division

showing above the line to the left of the

thimble.multiply that number by 1 mm.

2. If there is a half-milimeter line showing

below the index line, between the whole

milimeter and the thimble, then add 0.5

mm.

3. Multiply the number of the line on the

thimble that coincides with the index line

times 0.01.

4. Add these products.

Prepared: MFM 71

17 lines above the index line 17×1=17

1 line below the index line 1×0.5=0.5

11 lines on the thimble 11×0.11=0.11

Total reading =17.61 mm

Prepared: MFM 72

REVIEW QUESTIONS1) Read the following standard micrometer

setting.

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2)Read the following metric micrometer settings.

Prepared: MFM 74