Jeez! It really can't be this difficult!!!

I have been pulling my hair out for DAYS now trying to home/zero/locate my cutting tip!!!!

Is there NO way to tell LinuxCNC exactly where my tool tip is???

I have a completely manual tool holder. When I change a tool they are NEVER in the same place! Holder

If I chuck a 1" x 6" long piece of round bar, I should be able to move the tool tip X axis up to the work piece and tell LinuxCNC that the tip of the tool is at .5" radius or 1" diameter. No matter what I try I can't seem to do what I believe to be something so simple. The same should be true for the Z axis.

If a person manually inputs the tool location you should not need offsets, correct?????

I have entered my tool in the tool table with tip radius and geometry. NO offsets.

What is the purpose of "homing" the X axis?? the home of X is derived from the Outside Diameter of the work piece. When You home X it should ask for the OD and calculate the "zero" center line.

I have been using G92.1, and G92.2 to try and clear all offsets but some remain, is there a way to easily zero all offsets?

If I use tool touch off (X) it looks correct in the display but I can't advance more than one thousandth toward the center-line. WTF!

If I use touch off it just moves the work piece relative to the center-line??? Why should it EVER do this????

I have RTFM many times over and searched other forums, looked at umpteen videos and tutorials and now I am mentally exhausted!

This seems to be VERY buggy! but it is probably something simple I am just not getting :pinch:

If anybody is kind enough to take their valuable time to try and help me I would greatly appreciate it and will pay it forward by helping someone else!

What is the purpose of "homing" the X axis?? the home of X is derived from the Outside Diameter of the work piece. When You home X it should ask for the OD and calculate the "zero" center line.

Homing the axis tell linuxcnc where the machine is in relation to the machine's range of motion so the soft limits can work. This is in the G53 coordinate system.
On my lathe I set my X home position to be fully retracted from the work, towards operator.
So with home switch home the axis. Without home switch jog the machine to the home position and then click home.

When I change a tool they are NEVER in the same place!

There for linuxcnc does not know where it is.

Make sure all offsets are off.
Then you can measure your stock say 1". Jog the machine to just touch the work and then hit "touch off" (not home) and enter the correct dimension 1" diam or .5" radius. You could also use the dowel method and slowly jog off till the dowel clears and set the diameter for the stock size plus the dowel. I will normally make a light cut and measure the true size of the finish and then while the machine is still in that position touch off to that exact dimension. As long as you do not change tool numbers or your tool linuxcnc should indicate the correct dro dimension.

the home of X is derived from the Outside Diameter of the work piece.

Home is the home position of the machine, not the work piece. You can touch off to the outside diameter of the work piece and then tell linuxcnc what that dimension is.

Rick G

It would help to know what your trying, we can't guess and "I tried everything" is not much help.

Say "what I tried exactly", "what I expected exactly", and "what I got exactly".

and this may help...
gnipsel.com/linuxcnc/g-code/lathe02.html

JT

Thanks, JT
I have been pulling my hair out for DAYS now trying to home/zero/locate my cutting tip!!!!<----this!

I'm kinda new to this so it is hard for Me to explain what I am seeing/doing

Ok, So I found out what a major part of My problem was (beside being inexperienced) When I set up the steppers with the Stepper Configuration Wizard I had NO negative X travel it was 0 to +5, so after homing X I could not move X toward the work piece. I changed it to be -2.5 to +2.5 and all works well. It would be nice if someone within LinuxCNC would have mentioned this in all the documentation.



Thanks for the link, Carl

Every machine is different and can be set up in different ways. For example my CHNC lathe has the following for X min limit -4.640 max limit 0.250. X homes all the way out or nearly so. And for Z min limit -11.6 max limit 0.575. During setup I home an axis then jog to the limits and note them then adjust the ini file until the axis will not contact a limit switch.

In your case if you homed the X axis at the center of the lathe and had no negative travel allowance you would not be able to move back to you in the negative direction.

There is no possible way for the documents to cover all machine possibilities and I admit that I have tried in the past.

JT

Like John and as mentioned in the previous post I like to set X home as fully retracted (towards operator) as 0 or slightly positive and all the travel negative, same for Z 0 all the way to the right and all travel negative.

Rick G