The x axis ballscrew on my (very good) lathe was a vast improvement.
The stepper I used then == 2004 acted as a tiny brake when disabled, and as a break when powered.
The 3/4" 0.750" roton ballscrew was == 14 x more rigid than the original 16-17 mm acme screw on a 12x industrial lathe.
And had vastly less stiction and about 5x more power due to lower losses.
Now I use an ac servo of 750W for much more accuracy and rigidity.
I use servo-disable signal to turn it off for manual turning and enable it when I need a solid break.
Now finalising move to a new 32/5 mm ballscrew of much higher quality.
And direct drive vs HTD 8-30 mm belts at 1:2.
And 25 mm linear guides on x, and 270 mm movement for gang tools and 2 toolchangers vs 140 mm movement on gibs.
Either the belts or pulleys were inaccurate, and movement was not linear to a high accuracy with the bigger belts and pulleys in htd 8/30.
Part of the problem was likely the roton rolled ballscrew.
And the weak yoke linkage (rubbery) in version 3 of x axis mount.
So I had "bounce" where the x movement was sometimes erratic in unpredictable ways.
After 3 weeks and 150+ hours the new x axis is nearly done.
(temporary) Yoke needs fixing and then the servo needs a mount point.