My first successful self-calibration. So far I'm thoroughly enjoying this build.

My first successful self-calibration. So far I’m thoroughly enjoying this build. #Kossel

love the retraction method. Never seen that before.

Can the probe be auto-deployed for the next calibration? Perhaps there can be a small opening in a wall for the screw head to catch on? (That is how it is deployed, yes?)

Indeed it can, and is. If you look closely at the end of this video you can see the Kossel press downwards on the pillar. That pushes the probe upwards and when it gets high enough a spring pushes the top of the probe sideways so it won’t drop down again when the head lifts (the probe is shaped like an upside-down L – like an allen key).