What moves - the milling head or the table?

What moves - the milling head or the table?

When the mill is machining something, it is clear that, when you stand back from the machine, the milling head and the table both move, in Z and X - Y respectively.

However, when using a CNC milling machine, the only thing which matters is "what is the tool is doing?", not what the head or the table are doing. Always think in terms of it being only the tool which moves. This is specially important when in manual tool movement mode.

Movement in the Z direction is easy to understand. The tool obviously moves up or down when the Page Up or Page Down keys are pressed.

Correct thinking about tool movement in the X and Y directions takes a while to acquire because it feels contrary to what the eyes see. What you have to look at, all the time, is the end of the cutting tool and think about where it is going or where you want it to go.

Pressing the left cursor key makes the tool move to the left. True, the mill table is moving to the right but that is not the way to think about it: the tool is moving closer to the left-hand end of the table.

Pressing the right cursor key makes the tool move to the right.

Pressing the up cursor key makes the tool move towards the back of the table.

Pressing the down cursor key makes the tool move towards the front of the table.

When using manual tool movement mode, let your eyes focus on the billet and the end of the tool and think "Does the tool need to go to the left / right / front / back of the billet?" and very soon you will always press the correct key first time.

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