CHAPTER 2.0:HAND TOOLSCHAPTER 2.0:HAND TOOLS

PN NORAZLINA BINTI AHMAD SARAIDEPARTMENT OF MECHANICAL ENGINEERING

1.Marking Tools1.Marking Tools-These are sub classified as steel rule, -These are sub classified as steel rule, straight edge, flat steel square, straight edge, flat steel square, sriber,divider, prick punch, centre punch ,try sriber,divider, prick punch, centre punch ,try square,vernier protractor , and surface square,vernier protractor , and surface gauge.gauge.

2. Measuring devices2. Measuring devices-Commonly used measuring devices and -Commonly used measuring devices and instruments used in fitting shop are surface instruments used in fitting shop are surface plate, try square, plate gauge,surface plate.plate, try square, plate gauge,surface plate.

Tools used in mechanical fitting workshop

Measuring Toolsa)Steel Rule

Steel rule is a linear measuring instrument having 1.0 to 0.5mm accuracy.

It is also used for drawing straight lines.

b)Scriber

It is used to mark or scribe lines on the workpiece.The two end are very sharp and have a knurled

handle in the middle.

c)Try Square

Try square is used for checking or marking right angles 90 degree accurately.

It consists of a steel blade , riveted into a hard wood stock which has a protective brass plate on the working edge.

d) Compass or leg-end pointer

It is used for marking lines and circles on the workpiece.It has a pair of steel legs which are hinged at the top.One of the ends is bent and the other is pointed

e) Spring dividerIt is used to mark the dimensions from scale to

the workpiece. It is similar to the compass and is used for more

accurate marking. The spring divider has a screw with a knurled nut.

f) Calipers: These are used for measuring inside and outside diameters and linear dimensions. There are two types:

Firm joint calipersSpring calipers

g) Firm Joint Calipers: These are of two types:

(i)Inside caliper(ii)Outside caliper.

The size taken on the calipers is measured on the steel rule.

It consists of two legs connected together at one end by means of a friction joint.

i)Inside CaliperIt is used to measure dimensions such as

diameter of a hole width of a slot.

ii.Outside Caliper: It is used to measure outside dimensions

such as diameter of a rod thickness of a plate .

h)Spring Calipers:

These are operated by means of a screw and a knurled nut.

It also consists of two legs which are hinged together at one end.

The advantage of the knurled nut is that it can be easily operated by hand. It is very convenient and takes less time in setting

i)Centre Punch: It is used to mark a centre for a hole to be

drilled. It can also be used for marking points along a line for cutting. Its tapered point end has an angle of 60 degrees.

j) Dot punch: It has a sharp point end which is used to make punch marks along a line on the workpiece. Its tapered point end has an angle of 40 degrees

k) Surface Plate:

It is used to check the surface flatness or straightness of the workpiece.

It is made of grey cast iron. The top surface is machined smoothly and finished accurately.

It is also used as a reference surface for marking with the scriber block. The figure demonstrates the use of surface plate for marking on a workpiece.

l) Vee blockV-block is used for setting and holding the

round and cylindrical objects very often and to determine the centre or circular objects.

It is made up of cast steel.

m)Combination set