Auto-Squaring with LinuxCNC v 2.8

[Kitwn]

I suppose it was bound to happen. I wanted to change my X axis upper soft limit so I did what I've always done: ran Stepconf and changed it. Opened LinuxCNC and ran homing. Only one X axis motor started moving, the E-stop did nothing (that'll be something else to investigate ASAP) and the gantry alignment looked very sorry for itself by the time I turned off the motor PSU.

Once you set up a two motor axis as described above you MUST NOT run stepconf but make the relevant edits to the .hal and .ini files manually instead. I have saved versions of the .hal and .ini files for my machine so reloading was no problem. Fortunately there's no real damage done as the motor stalled before bending anything but the gantry-to-carriage bolts have clearly moved as the gantry will square itself when homed but visibly 'relaxes' when the motors are disabled with one side carriage moving a few millimetres along it's rail. An hour or so with a spanner and the big square required tomorrow morning.

I think I might create a new wallpaper for my LinuxCNC computer that has "DO NOT RUN STEPCONF!" written on it in big shiny letters. I can't be the only person to have suffered this lapse of concentration and if there's a way of easily disabling stepconf or preventing it from overwriting the relevant files I'd love to hear it.

Kit

PS As you may have realised my machine does not use fabulously rigid Hi-Win rails on its axes but has fully supported 20mm round rails with two linear bearings on each side screwed to a plate which the gantry then bolts to. There is about +- 3mm of easy movement between the carriages with the motors disabled. Once it's squared and the motors are energised everything is nice and stiff and the cutting is sufficiently accurate, but the auto-squaring is definitely a good improvement for a machine with so much slack on a two-motor axis.