Current Klipper logic for max X and Y doesn't seem to make sense and it prevents only the less damaging type of crash

[Sineos]

@tinkerman

I am sorry @Sineos, I did read your homing theory article and I am not criticizing it, but the concept behind it.

I do not take it as critics. On the contrary, I’m happy that someone is actually reading it and I’m also happy about any form of input / critics / corrections.
In the end, I’m not writing these KB articles for myself but as a guide / aid for the users of Klipper.

@tinkerman

Now, if the max position actually represent valid print moves, then the endstop will indicate where are both the origin and the end of the bed, which to me makes a lot more sense. If endstop is over the inside of the print bed, then endstop position and max position would be the same and it would also prevent both frame and nozzle crashes.

So, if I understood correctly, your input boils down to: Do not home the Z axis, if the probe position is outside of the bed.

While I agree that this would be an useful sanity check, I have no idea what this would mean code wise. As far as my understanding goes:

• Klipper today has no notion about the bed size
• Klipper today only knows its kinematic limits (endstop positions and min/max limits only refer to the kinematic limits and define the bed’s origin relative to these limits)
• Additional settings, e.g. bed size or “gap” sizes would be needed along with the respective logic in the code

FWIW, an overhaul of the Klipper homing code is tentatively planned. Of course the final due date and potential scope is open and subject to change.