Creality Ender 3 Pro print head drops in standby

[Roberts_Clif]

I have posted about this before.
T8-8 Lead-screw Drop with Gravity


Image of three lead screws T8-8mm pitch (4 start), T8-2m pitch (single start), and All thread 1.25mm Pitch.
All turned exactly 360 degrees. I started with a cheap 3D Printer it came with the all thread.

Lead screws 3.jpg
Now the All Thread worked but it had it own problems.
1st it was not a very true lead screw and wobbled.
2nd it always squeaked always needed cleaned always accumulated dirt.
3rd the threads were gummed up and even a little dirt caused problems.

The T8-8 (4 start) lead screw always needed me to make adjustments to the Z-Axis.
It was always out of sync with the other Stepper on my dual stepper Z-Axis Prusa i3 type Clone.

However on a single Z-Axis system like my MPCNC the T8-8 (4 Start) lead screw works fine.
The Homing auto-corrects any drop in the Z-Axis.

I would Never go back to a T8-8 (4 Start) lead screw again for a Z-Axis bearing weight.
It took me a while to learn this so I have a few of these lead-screws.
Including a set that was given to me, I ordered a T8-2 lead screw they sent me a T8-8 lead-screw then a replacement saying keep the other.