Anyone changed out their lead screw(s)

As I understand it, most inexpensive 3D printers use lead screws that have 8mm lead. They’re 8mm diameter with a thread pitch of 2mm. They also are quadrupal threaded: i.e. they have 4 thread starts. These 4 thread starts times the 2mm pitch gives a lead of 8mm, meaning 1 turn of the lead screw will move the nut 8mm. A single threaded lead screw with 2mm thread pitch will only move the nut 2mm, giving finer control.

Has anyone tried swapping out a screw with 8mm lead for 1 with 2mm? If so, did you see any difference in quality? Was it worth it? Bear in mind, new lead screws are not expensive, usually well under $40.

I have a counter question: Why :smiley:

The current pitch already needs multiple stepper steps per 0.1mm z movement. Usually around 400steps/mm, so 0.1mm requires 40 steps/mm and 0.01 is 4 steps/mm.

So why you want to replace the lead screws, unless they are somehow bend? A finer pitch just would add more inconsistency as the lead screw needs to be even more perfect to avoid z wobble.

I would rather try to improve the print quality by using a fiber enhanced gt2 belts and dump the lead screws. This would cause additional problems like the requirement of a backlash mechanism, so the z axis won´t drop on stepper power loss. But I guess it would improve the print quality as there won´t be any wobble caused by the lead screw anymore and ringing caused by the belt shouldn’t be a problem, as the bed is heavy and the moving speed is low.

  1. I was curious. Has anyone tried it & what results did they get?
  2. A single thread screw means any 2-digit layer height falls evenly on a stepper value, so there’s no need to be concerned about using, for example, 0.15 layer height.

I’m not sure about the Z wobble. The couple of videos I watched of people who’ve done didn’t mention any wobble issues, except for bent rods. They also talked about installing spider/plum couplers for the lead screws, to help reduce Z coupler compression issues.

I’m trying to figure out what a lead screw is on a 3d printer. It seems to have something to do with the Z axis but I am lost.

With your construction experience I’m surprised you haven’t heard of lead screws. On your printer, the lead screw is the 1 that moves the Z axis up & down. The Z axis stepper motor drives it.

Actually I was reading some posts and saw what it was. It is the terminology I wasn’t used to.

I’ve had automatic garage doors before but I never knew that the rod was called a lead screw.