I am using Mach3 Lathe and getting ready to make my first cut.  Thought I would start out with the OD Facing wizard.

I set X Start to zero to face from the centre outward.  However the simulation always starts X beyond the centre line by the amount I have entered for Z Clearance.  This in radius mode.  If I am in diameter mode X starts beyond the centre line by twice the amount I have entered for Z Clearance.

I can get the wizard to work by entering values for X Start based on the above rules but I would like to understand why I cannot use zero for X Start.  Is this just the way the wizard works or am I missing something.

Dennis

Hi
What figure are you putting in for the z clearance?

Personally, unless it there is an ID on the part, I would work from outside to centre when facing.
That however is not your question, what you will need to do is have the Z clearance just marginally larger than your roughing cut depth.
For example if you have a rouging depth of 0.5mm then set the clearance to 0.501 and you should get more or less what you want.
Hood

I think you also have to compensate for the tool tip radius also when starting beyond center to cut the face completely.

I was using a z clearance of .25.  As suggested by Hood I adjusted the Z clearance to just a bit more than the roughing cut and the X cut only starts that amount beyond the centre of the piece.  So I guess that is just the way the wizard works.  If you want to start your cut at the centre of the piece you have to set X Start equal to Z clearance.  I can live with that idiosyncrasy of the program I just wish I knew why it worked that way.
Tool tip radius?  I have not looked at that, need to learn to walk before I try running.

Now to try and understand machine coordinates and program coordinates.

Now to try and understand machine coordinates and program coordinates

Attached should help.

RICH

Hi
I just started up my home made slant bed lathe and was programming using the wizard. I put in the numbers and was posting the code and got up a warning: ...FilletRadius is too big...
The filling radius was +0.000
I tried to change the values but it did not go away. I also re-started Mach3 but warning is still there.

Another question, when jogging the Z axis the arrow key on the pc keyboard is opposite How can I change this? The X is correct. The Z is correct with regards to +/- + is towards the chuck.

- should be towards the chuck, sorry.

How can I change this?

Config>System Hotkeys Setup
Click the jog hotkey of choice and then touch the associated key on the keyboard.

RICH