Threaded Rod Stepper L500 Tr8*8 Leadscrew
Nema17 40mm Stepper 1.2A
500mm Tr8*8 Lead Screw
Threaded Rod stepper is more reliable and precise than Motor, Coupler and Lead Screw combination.
Some of the builders are chasing for resolution, small pitch and single start lead is the choice. Tr8*2 or Tr8*1 Lead Screw is solution of this kind. These threaded rod stepper owns self-locking function with the POM Nut, it's recommended for Z-axis.
And some of the builders are looking for fast printing, small pitch but large lead are well option, Tr8*12, Tr8*20 are of this kind.
X or Y Axis precious solution with Threaded Rod Stepper
Tr8*8 Lead Screw is an intermediate choice for resolution and speed.