CHESTER Cobra Mill, Instruction Manual

Page: 26 / 29

7.1. Vice Alignment
In the setting up of the vice onto the machine
table, the fix jaw of the vice must be set
parallel to the machine table using a Parallel
Bar and a Dial Indicator as illustrated in figure
21. Adjustments can only be made by using a
hide face hammer to correct its position such
that a near zero indicator movement is
achieved at all positions along the parallel
bar.
Figure 21. Machine Vice Set­up
7.2. Work Holding Method
In the machining of a complex component, it is usually started off with the milling of a rectangular block.
To ensure that each surface of the rectangular block is perpendicular to its neighbouring surfaces, the
following points should be noted:­
· The vice jaws and the workpiece must be free from burrs, chips, and cutting fluid.
·
Smaller workpiece should be supported by parallel bars to provide the supporting datum.
·
Round bar must be placed between the workpiece and the movable jaw to ensure that the
workpiece is in perfect contact with the fix jaw.
· The vice handle should be tightened by hand to avoid over clamping of the workpiece as well
as the vice. Hide face hammer should be used to assure that the workpiece is in perfect contact
with the supporting base.
· On completion of the milling of the first face, the workpiece should be unloaded, deburred, and
cleaned before the next operation.
· To machine the second and the third faces, the workpiece should be clamped with its
preceding machined surface facing against the fix jaw of the vice.
· Similar clamping method can be applied in the machining of the fourth face.
· Yet it can also be clamped on the vice without the round bar.
· Both ends of the workpiece can be machined with the periphery flutes of the cutter using up cut
milling as shown in figure 23.
Figure 22. Holding Method by Using a Machine Vice