284 Machine Drawing
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Fig. 18.13b Multiplate friction clutch
18.3 Machine Tool Parts and Accessories
18.3.1 Single Tool Post
Tool posts of several designs are available to support and hold the cutting tools in lathe machines.
Figure 18.14 shows the part drawings of a single tool post, which supports one cutting tool at a
time and is used on small sized lathes. This unit is fixed on the compound rest of the lathe
carriage.
The single tool post consists of a circular body 1 with a collar at one end and a threaded hole
at the other. A vertical slot is provided in the body to accommodate the tool/tool holder. The body
is slid through the square block 5, which is finally located in the T-slot, provided in the compound
rest. The design permits rotation of the body about the vertical axis. A circular ring 4 having
spherical top surface is slid over the body and the wedge 3 is located in the vertical slot.
The tool / tool holder is placed over the wedge. By sliding the wedge on the ring, the tool tip
level can be adjusted. The tool is clamped in position by means of the square headed clamping
screw 2, passing through the head of the body. Figure 19.8 shows the assembly drawing of a
single tool post.
Exercise
Assemble the parts of a lathe single tool post, shown in Fig. 18.14 and draw, (i) half sectional view
from the front and (ii) view from the right.
18.3.2 Square Tool Post
This is used to hold four different tools at a time. The tool holder may be rotated and clamped to
facilitate the use of any one of the tools at a time. The details of the square tool post are shown in
Fig. 18.15.
The tool holder 1 is located on the base plate 2 by means of the stud 3. It can be fixed to the
base plate in any position rigidly by the clamping nut 4 and handle 5. The knob 6 is fitted to the
handle for smooth operation. The tools are held in the tool post by means of the set screws 7. Each
