Taper turning methods in lathe machine
There are four methods
1. Form tool method
2. Tailstock set over method
3. Compound rest method
4. Taper turning attachment method
Form tool method
This
is one of the simplest methods to produce short taper. This method is
shown in the above figure. To the required angle the form is grounded.
The tool is fed perpendicular to the lathe axis, when the work piece
rotates.
The
tool cutting edge length must be greater than the taper length. Since
the entire cutting edge removes the metal, it will produce a lot of
vibration and hence a large force is required. It is done in slow speed.
Tailstock set over method
Generally,
when the angle of taper is very small this method will be employed. The
work piece be placed in the live center and live center. Now, the
tailstock will be moved in a cross wise, that is perpendicular to the
lathe axis by turning the set over method. This process is known as tail
stock set over method.
Hence
here the job is inclined to the required angle. When the work piece
rotates the tool is moved parallel to the lathe axis. So that the taper
will be generated on the work piece.
Compound rest method
Generally
short and steep taper will be produced will be produced using this
method. In this method the work piece will be held in the chuck and it
will be rotated about the lathe axis. The compound rest is swiveled to
the required angle and then it will be clamped in position.
The angle is determined using the formula, tan
Then
by using the compound rest hand wheel the tool will be fed. Both the
internal and external taper can be done using this method. The important
feature is that the compound rest can be swiveled up to 45° on both
sides. Only with the help of the hand the tool should be moved.
Taper turning attachment method
In
this method by using bottom plate or bracket, a taper turning
attachment is attached to the rear end of the bed. It has a guide bar
which is usually pivoted as its center. The guide bar has the ability to
swing and it can be set in any required angle. It has graduations in
degrees. On either side, the guide bar can be sweivelled to a maximum
angle of 10°. It has a guide block which connects to the rear end of the
cross slide and it moves on the guide bar. The binder screw is removed,
before connecting the cross slide, hence the cross slide is free from
the cross slide screw.
Usually during taper turning, the job will be held in the chucks or in the centers. To the required angle the guide bar turned.
The angle is calculated using the formula, tanα = (D-d)/2l
When the division is given in mm instead of degree, then the angular distance of the guide bar to be tilted is given by
Using
the compound rest hand wheel the depth of cut will be given. At an half
taper angle the guide will be set. Using this method any taper turning
method can be done.
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