@mrehorstdmd As it is there is a belt reduction drive running the main axis drive belt which increases the steps per mm to more than the typical 4 start TR8 (without using 0.9 steppers) with negligable backlash.
I'll have another look at worm drives another time but recovery after power cut is not a significant concern for me. When I begin to get concerned by that I'll look at UPS. Thankfully power dips/spikes/cuts are rare here and I don't run long unattended builds.
All that said while advocating the use of worm drives based on power cut recovery doesn't excite my interest it is more appealing from a risk assessment perspective the probability of the worm drive system failing to stop an axis in power cut is far lower than a cam operated brake and diagnostic coverage is naturally a part of standard running.