MODELS FOR
PRACTICE IN WORK SHOP
UNIT I: TURNING
PRACTIC -24 Hrs (NOTE: INDIVIDUAL MODEL)
1.
To make the part shown in the sketch from a mild
steel rod on a Lathe
 |
EQUIPMENT: List all tools and instruments used.
OUTLINE OF PROCEDURE
Hold the bar
in a three jaw chuck and face the end with a right hand facing tool. Make
central hole with a center drill. Repeat these' operations for the other end of
the bar. Replace the chuck by a dog plate (Center plate) and hold the job in a
carrier between centers. Turn the bar to the required diameter with rough cuts.
Face the steps and finishes the diameters to the required sizes. Machine the
roots and the groove with form tools. Machine the taper with the help of the
cross-slide swiveling arrangement. Knurl the required surface. Cut the threads.
OBSERVATIONS
(a)
Measure all dimensions (up to second decimal place) on the specimen
turned by your group. Make a neat sketch and indicate all measured dimensions.
(b)
Discuss briefly how tapered portion was turned.
(c)
Show the calculation of the required gear ratio for thread cutting.
(d)
Sketch the main drive unit of 'the- lathe and show how the speed steps
are obtained.
UNTII: DRILLING
PRACTICE -12Hrs (NOTE:
INDIVIDUAL MODEL)
 |
2. To
drill, file, as shown in the sketch, out of the work piece provided and tap
holes on
the mild steel
plate.)
OBJECTIVE: To study the characteristic features of Drilling
machine.
OUTLINE OF PROCEDURE
i) Run the machine at low speed
and observe the motions, which control the shapes of the surfaces produced.
Note particularly the features, which control the geometrical form of the surface.
ji) Learn the names of the major units and the components of each machine.
Record these details (Table A). (Please ensure that the main isolator switch is
off and check that the machine cannot be inadvertently started. Do not remove
guards). Use the manufacture's handbook for details that cannot be inspected.
jii) Record the obtainable
speed and feed values
iv) Note down the special
features of the speed and feed
control on each machine,
v) Pay attention to the following:
a, Size specification of various machine tools,
b, Machine tool structures and
guide ways I slide ways.
b. Drive mechanism for primary
(cutting) motion,
c. Drive mechanism for
secondary (feed) motion.
UNIT III: SHAPING PRACTICE -12Hrs (NOTE:ONE
MODEL FOR GROUP OF 05 STUDENTS)
3. To
machine a V-block as shown in the sketch out of the work piece provided.