Correct lathe spindle and x axis directions

[benscale160]

OK, so this is probably straight from the lathe 101 beginning class. I'm a little confused as to which direction M3 and M4 command with respect to rotation. I know M3 commands a clockwise direction. And M4 commands acounterclockwise direction.

I suppose the confusion stems from operating a CNC mill. On the mill, the M3 of course does the same thing by commanding a clockwise direction. And this is the direction that is used for right hand cutting tools.

On the the lathe M4 is used for right hand cutting tools such as drills, taps, and reamers.

I suppose it's all a matter of perspective as to which side of the spindle you're looking at. On the mill you're looking at the top of the spindle. On the lathe your essentially looking at the bottom.

Also, is the X travel direction reversed? Because on the mill, the table travels left for a positive move. On the lathe, the x axis moves away from the operater for a positive direction move.

I mean it is what it is, but I'm just hoping that somebody can offer a simple explanation.

Thanks
Ben

[DICKEYBIRD]

M3 is CW looking at it from the back side of the spindle or chuck. It's what you & I would call the "normal" direction. I had the same confusion at first.

The X moves away from zero for a positive move.

[Dave_C]

Also, is the X travel direction reversed? Because on the mill, the table travels left for a positive move. On the lathe, the x axis moves away from the operater for a positive direction move.

It is confusing only because we get use to thinking in terms of "table movement" instead of "Tool Movement".

Both a lathe and a mill will have the same tool movement for an X positive move! The tool will move away from "0" and to the right for a mill but a lathe can move the tool toward you or away from you depending on the tool post position. IE: Front tool post moves toward you, a rear tool post would move away from you. Both are moving the tool away from the centerline. (And would be programmed with positive numbers)

There are exceptions such as how Tormach sets up their Lathe so that rear tools are positive numbers and anything in front of the center line is a negative number. They stay with the true cartesian coordinate system because they use both front and rear tools at the same time and so they can not just make it an option to chose front tool post and have positive numbers from the centerline or rear tool post and still have positive numbers.

I hope that doesn't confuse more than it helps.

Dave C.

[cncsnw]

On the the lathe M4 is used for right hand cutting tools such as drills, taps, and reamers.

If this is the case, then your control is not set up correctly.

Whether on a mill or a lathe, M3 (forward) is clockwise rotation viewed from the back of the spindle, and is the direction you would use for twist drills and right-hand taps.

[benscale160]

Just to make sure I understand:

X is positive moving away from centerline. Ok makes sense.

So in theory I should never see a negative X number unless I'm looking at my machine position because the machine is homed at the furthest point away from centerline from x. Or in the case where the tool would travel slightly beyond to finish a facing operation.

M3 is clockwise viewed from the rear and is used for right hand turing/facing tools, drills, taps, reamers, etc.

In manual mode, M3 CW is activated with the
button.

M4 CCW is activated by the button.

I will need to swap two wires between my 3ø motor and VFD and prob assign a negative value to my spindle encoder in the wizard.

Thank you everybody for all your help.

Ben