1. A tool is an object used to perform work . The tools being
referred to hand tools and power tools are a common
part of our everyday lives and are present in nearly every
industry. These tools help us to easily perform tasks that
otherwise would be difficult or impossible.
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2. Classified into two categories :
Hand (Manual) Tools
Power Tools
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3. No external power required
Broad range of tools from extremely simple to more complex, such as:
HAMMER HACK SAW SPADE Bull float
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4. Measuring tools The very first activity involved in any operation
laying out tools Second activity involved in any operation
Holding tools Third activity involved in any operation
Cutting tools Finishing activity involved in any operation
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5. Measuring is the process of making Dimensions Required to the
needed job before any other processes will be applied .
Some Important measuring Tools :
1.Steel Ruler : The still rule is a Stiff Straight steel Strip having
all the face machined true. On one of the faces graduation are
marked in Inches and Centimeters It is use to set out Dimensions.
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6. Dividing of Steel ruler 10 mm = 1cm
0.5
1 cm0 cm 1 mm
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7. It is made of steel and is used for linear measurement where standard
rules are not long enough As it is rolled up in a very small housing it can be
easily carried in a pocket it over all length 3(10 ft) to 5 meters use usually.
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8. A engineer's square (machinist square) is the metalworkers' equivalent of a try
square. Machinist try squares are made entirely from metal to guarantee accuracy.
The engineers try-square imposed of two parts, the stock and the blade. They are
usually made from bright mild steel with the blade being hardened.
STOCK
BLADE
90
9. Bagerhat Technical
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A combination square is a tool used for multiple purposes in
metalworking. It is composed of a ruled blade and one or more
interchangeable heads that may be affixed to it. The most common head is
the standard or square head which is used to lay out or check right and 45°
angles.
10. A caliper is a device used to measure the distance between two opposite
sides of an object. A caliper can be as simple as a compass with inward or
outward-facing points. The tips of the caliper are adjusted to fit across the
points to be measured, the caliper is then removed and the distance read by
measuring between the tips with a measuring tool, such as a ruler . It is used
in many fields such as mechanical engineering, metalworking,
woodworking, science . The inside calipers are used to measure the
internal size of an object.
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11. Outside calipers are used to measure the external size of an object.
The same observations and technique apply to this type of caliper, as for the above inside
caliper. With some understanding of their limitations and usage these instruments can provide a
high degree of accuracy and repeatability. They are especially useful when measuring over
very large distances, consider if the calipers are used to measure a large diameter pipe. A venire
caliper does not have the depth capacity to straddle this large diameter while at the same time
reach the outermost points of the pipe's diameter .
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School & College.
12. The vernier, dial, and digital calipers give a direct reading of the
distance measured with high accuracy and precision. They are
functionally identical, with different ways of reading the result.
These calipers comprise a calibrated scale with a fixed jaw, and
another jaw, with a pointer, that slides along the scale. The distance
between the jaws is then read in different ways for the three types.
Dial caliper Digital caliper
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13. 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 of an object or a hole
4. Main scale: scale marked every mm
5. Main scale: scale marked in inches and fractions
6. Vernier scale : gives interpolated measurements to 0.1 mm or better
7. Vernier scale: gives interpolated measurements in fractions of an inch
8. Retainer: used to block movable part to allow the easy transferring of a
measurement
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School & College.
