Homing to sides of workpiece with real tool How? Lathe

I try again. Now I see cross hair G43 on the screen but now everything have moved with it, including the 0,0 point and when I do the
G00 X0 Z0
The tool goes to 1.5mm from the cross hair G54 zero and the tool centre shows yet again OUTSIDE the shown 0,0 and all the machine path have moved too so I have nothing really achieved.

Either I still do not understand this or it is not working as expected?

I think you are getting close.

One way to think about it is that the tool touch off button allows you to establish tool offsets if you are using multiple lathe tools based on a reference. That reference could be a dowel pin in the chuck, stock in the chuck or a some point away from the chuck such as a tool setter arm. It established the relationship between each tool. It does not define the G54 etc location.

Touch off established the G54 location.

What's important is that you issue the G43 during the tool change so the proper offset gets loaded when you then position the tool to the G54 position.
Jog your selected tool to the material in the chuck and touch off to the face for Z0,(in your case enter 1.5mm for the Z) then touch off the diameter, measure it and add that number to the entry box. (diameter/2 +1.5mm) note the X axis has to be selected or you'll override the previous Z value.

To test it, jog away from the part and go to MDI and enter G01, Z10 X0 F200. Tool center should come to a stop 10mm from the face and in center line of the rotational axis.

it maybe a tool orientation problem here is the manual link that may help.
linuxcnc.org/docs/html/lathe/lathe-user.html

Hello all,
Another day spent and I can say 100% for sure that this does not work as intend and described. It is in my so bad that is is unusable as it ruins workpieces.

The problem is repeatable but I have no solution.
I use a feeler gauge to keep the tool 0.1mm away from the workpiece. I thus home the X and Z axis respectively.

I then use "Tool touch" off as described by OT-CNC and others and enter X 0.1 and Z 0.1`.

At this point, "it" enters X 0.1 and Z -0.1 into the tool table for the tool used.
NOTE that one is + and on is - although I entered (+) 0,1 for both touch offs values.

Now if I do it all again (for theoretically another workpiece), and use the same "Tool touch off" entering (+) 0.1into both Z and Z, it enters 0.233 into X and -0.1 into the Z of the tool table.
That makes not sense.

The tool then crashed into the workpiece on G00 X0

Here is the worst part:
I then revert the tool table by editing it and deleting the X and Z values it entered.

It makes no difference. The tool will now ALWAYS be off by some amount.
I have deleted the tool table,
Created a new one, (yes, I reload the tool table every time)
Re-started Linus CNC
Re-booted the PC

None of it makes any difference. When I hoe the axis, the previously accumulated tool touch offset is still present and it is impossible to get the X and Z to show 0 after homing.

I have no idea where it stores these values but it is definitely not in the loaded tool table.


The only way to get it undone is to see what it shows after homing for Z and Z and enter the opposite values into tool touch off.
Thereafter, the tool table has to be cleaned again.

Surely other folks have come across this issue? It has unfortunately ruined my workpiece when I ran it the second time round.

Regards
Bernt

I'm sorry you are still having trouble with this. If your part zero is the front of the stock, you should be able to face it then enter Z0 for that loaded tool in G54. Your program also has to reflect G54 with Z0 from the faced stock. Your program should have a positive Z retract position to start so you don't crash into the stock. I always do a dry run either with Z0 away from the part or remove the material from the chuck to prove out the program. Sometime I run it in plastic first if I'm not 100% confident. What are you using to generate the G code?

I use a feeler gauge to keep the tool 0.1mm away from the workpiece. I thus home the X and Z axis respectively.

I think you are still confusing homing with part zero or work offset (G54). Homing is done so the machine knows where it's 0,0 is when you 1st power up. I assume you don't have home switches on your machine? If so I would add them and configure your ini to reflect the overall travel so linuxcnc knows the soft limits of travel. This way when you power up, the machine always homes to the same place and establishes it's reference. It sound to me you always have a different home when referencing to your stock? You need a repeatable reference which are home switches.

There are three things that need to happen:

1) Homing, so that the machine knows where absolute zero is
2) coordinate system toucj-off, so that the machine knows where on the axes you want the G-code origin.
3) tool offset setting, so that 0,0 is the same for every tool.

Can you run through the sequence from startup, and be clear which tool you have loaded and which touch-off button you are using?

OT-CNC wrote: I'm sorry you are still having trouble with this. If your part zero is the front of the stock, you should be able to face it then enter Z0 for that loaded tool in G54. Your program also has to reflect G54 with Z0 from the faced stock. Your program should have a positive Z retract position to start so you don't crash into the stock. I always do a dry run either with Z0 away from the part or remove the material from the chuck to prove out the program. Sometime I run it in plastic first if I'm not 100% confident. What are you using to generate the G code?

I use a feeler gauge to keep the tool 0.1mm away from the workpiece. I thus home the X and Z axis respectively.

I think you are still confusing homing with part zero or work offset (G54). Homing is done so the machine knows where it's 0,0 is when you 1st power up. I assume you don't have home switches on your machine? If so I would add them and configure your ini to reflect the overall travel so linuxcnc knows the soft limits of travel. This way when you power up, the machine always homes to the same place and establishes it's reference. It sound to me you always have a different home when referencing to your stock? You need a repeatable reference which are home switches.

Maybe I am confusing something but even then, I should get repeatable results.
My machine does not have switches and most machines apparently do not and I also can't see a reason for them.

Let me start from the beginning.
1) My G-code has it's reference at the front right corner of the workpiece final size.
2) My chucked workpiece is the final size for OD and Z for this experiment
3) I start up
4) I move to the right, clear of the workpiece.with my tool in the toolpost.
5) I move in and then slowly to the left with a 0.1 feeler gauge on the workpiece face.
6) When the tool reaches the feeler gauge, I home the Z axis.
7) I move the tool out and to the left so I can move towards the OD, again with a feeler gauge.
When reached, I zero the X axis.
This should, in my opinion, put the machine 0,0 outside my workpiece in a safe place. (Currently this does not produce a 0,0 on the coordinates. I cannot explain that. I did before)
10) I move the machine 0,0. (That worked before in putting it front right of the workpiece but now recently it will crash into the workpiece for unknown reasons)

Next, I now load the file.
9) I enter T2 M6 to load tool 2
10) I I click tool touch off for X and enter 0.1 into the box.
11) I click same for Z and also enter 0.1 into the box.

Now I should be set to go. When I go to 0 on either axis, the tool will touch the workpiece either on the face or the OD.

During this process, my tool table changed by itself to have the entry of Z -0.1 and Z 0.1.

It all seems to work ok. Until I now restart the whole process.from step 1.

The tool table with change by itself then to have something like X-0.22331 and Z+0.1.

I am not able to get the homing done nor can I get the tool to end up at the correct 0,0 place.
If I repeat the whole lot again, the tool table will change to have X-0.33?? and Z 0.1.

Whatever I do, it never works as expected again and that is currently where it sits. When I restart, and click home X, it now shows 0.40 and for Z it shows 0.

Deleting the obscure accumulating values from the tool table do not seem to make any difference.