Reference lathe

Hi Guys,

I'm banging my head.  I have a back lathe, I want X=0 (G53) to be at the center of the spindle.  My positive X is on top (top) and my reference is too.  
There are two situations or it refers up there and it becomes zero then I don't have my X=0 in the center of the plate or I inform "HOME_OFFSET= 100" for example then it references up there and it goes down 100 (considering that the 100 would be the distance from the reference to the center of the plate), but I don't want that.  I would like it to reference up there normal, but stay up there with the value of 100 positive, then when calling G53 or X=0 it comes to the center of the board.  Does anyone have any suggestions?

Ingo

I think a drawing would help visualize exactly what you want verses what you are getting (to help us) Could you post even a pic of a hand drawn diagram? Your INI file would be helpful.

Also when you say you want X=0 be the center of the spindle, what will be in the center of the spindle? A reference tool tip?

Did you try BACK_TOOL_LATHE = 1 in your ini config?

See: linuxcnc.org/docs/html/config/ini-config...ha:ini-configuration

I am sending the same hand drawing as it is today and as I would like it to be.  I used HOME_OFFSET, this is closer to what I got but I don't want my X axis to move after the reference… I would like to leave my G53 at the center of the spindle, which is the same center as the turret in the center drill tool.

Yes I'm using this exact configuration

I tried it but it didn't work. Actually putting on the same line HOME_OFFSET = 100 _and_ HOME_POSITION = 100 (or probably 99) didn't work, if I put one separately under the other HOME_OFFSET = 100 and HOME_POSITION = 100 (or probably 99) opens but I noticed no results. I didn't understand the function of the “HOME_POSITION”.

An unfortunate naming choice may be making this harder to understand.
HOME_OFFSET and HOME are two completely different things.
It would be better to call them ORIGIN_OFFSET and AFTER_HOMING_POSITION

Anyways it seems to me you need to find out the distance (in machine units) from the homing trip point to where your center tool is in center of the spindle.
Set that as the HOME_OFFSET, it will be a positive number (because it looks like your home switch is on the positive limits)
Then set HOME = 0 (so it moves to spindle center after homing, if that is what you want. On a lathe you may not want it to, in which case you would set it something close to the HOME_OFFSET)
And then you will surely need to reset you MIN and MAX LIMITS.

So one way to estimate this (if you have access to measure)
move your center tool to be in line with the center of the spindle this is where you want the origin.
measure from the home switch trip dog to the home switch (or limit switch if that is what you use)
This is approximately the distance for HOME_OFFSET and for MAX_LIMIT
Approximate because you can't measure it accurately.
it will be positive because (it looks like) you reference with your positive side switch.

Then of course MIN_LIMITS will be the total_limits - MAX_LIMITS)

This would be the closest example in the docs:
linuxcnc.org/docs/devel/html/config/ini-...witch_example_layout
The difference is that you want the origin (B in the diagram) to be somewhere in the middle.
If you move the B you move the scale too so 0 is where the B is.
The other difference is your home switch is on the positive side so the signs change.
Hope I didn't lead you astray

So cmorley, my exact distance from the reference point (upper positive limit) to the spindle center and also tool turret center is 102.63mm, or rather HOME_OFFSET = -102.63 and HOME= 0. Now tonight I did this more I have a problem that bothers me a lot. It's just that after referencing the axes, the X axis moves immediately to X=0, but I'd like it to be stopped up there. Is this possible?

Ingo

Sure You can tell linuxcnc to move anywhere you want

Then set HOME = 0 (so it moves to spindle center after homing, if that is what you want. On a lathe you may not want it to, in which case you would set it something close to the HOME_OFFSET)

set HOME to the same as HOME_OFFSET or something very close - linuxcnc might not like sitting on the limit switch

Bit I'm confused by the negative ( -102,63 ) what switch are you using to home to?