This type of drilling machines is
designed for medium to large and heavy work pieces. The machine is having a
vertical column mounted on the large base. The column is supported by radial
arm which can be raised or lowered to accommodate work pieces of different
heights. The arm can swing horizontally to any position around the column over
the work. The drill head mechanism for rotating the spindle and feeding the
drill is mounted on the radial arm can be moved horizontally to and fro from
the column then it is clamped at any desired position.
These three movements in a
radial-drilling machine when combined together permit the drill to be located
at any desired position. When two or more holes are to be drilled in a work
piece, the position of the arm and drill head is altered so that drill spindle
can be moved from one hole to another without altering the setting of the work.
If the work piece is too big it can be clamped directly on the base.
Parts of Radial Drilling Machine
The parts of radial drilling
machine are as follows:
(a) Base. Base of the radial drilling machine is a rectangular casting
and is supports column at one end and the other end is finished and provided
with “T” slots to hold the table or work pieces. In some radial drilling
machines two bases are provided for setting jobs for mass production. Loading
or unloading can be carried out on one base while drilling operation is carried
out on another.
(b) Column. It is mounted at one end of the base. It is a cylindrical
casting and supports the radial arm which slides up and down. A motor is
mounted on the top of column which imparts vertical movement to the radial arm
by rotating a screw passing through a nut attached to the radial arm.
(c) Radial Arm. It is mounted on the column and extends horizontally
over the base. The face is accurately machined and drill head slides over it.
It can be swung around the column. In some modern machines a separate motor
controls the radial arm.
(d) Drill Head. The drill head is mounted on the radial arm and it
drives the spindle. It is having mechanism for different speeds and feeds. The drill head slides over the
radial arm for adjusting the position of the drill. The drill head can be
clamped at any position on the radial arm after sliding.
(e) Spindle Drive and
Feed Mechanism. In some
radial drilling machines a motor is mounted at the overhanging arm. The motion
is transmitted to the drill head by bevel gears through a train of gears in
drill head the spindle speeds and feeds may be adjusted. In some machines the motor
is mounted directly on the drill head.
Types of Radial Drilling Machine
The radial drilling machines are
of three types, these are:
(a) Plain Radial Drilling Machine. In this type the arm is having
vertical and horizontal movement of the drill head along the arm and circular
movement of the arm in horizontal plane about the vertical column.
(b) Semi Universal Radial Drilling Machine. In this type of radial
drilling machine, in addition to the above three movements the drill head can
be swung about the horizontal axis perpendicular to the arm. This permits to
drill a hole at an angle to the horizontal plane.
(c) Universal Radial Drilling Machine. In this drilling machine in
addition to above four movements, the arm holding the drill head can be rotated
on the horizontal axis. All these movements in radial drilling machine enable
to drill on a work piece at any desired place at any angle.
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