Threaded rod wobble

I've been using my printer quite a lot and I've noticed that both the threaded rods have a significant wobble to them now... I'm pretty sure before they were quite sturdy but now they have at least 3mm of play on the X/Y axes. The right rod also can compress approximately 2mm down on the Z axis.

I'm certain the Z compression is not normal (I remember a thread a while back with someone asking about that) - am I remembering correctly that the X/Y wobble is new/not right? And if so, can someone please explain how to fix it?

 

How stiff are your smooth rods?

The compression coupling should have a stop on it to limit the end point of the threaded rods. If pressed up against this shouldn't be an issue.

My screws wobble a pretty significant amount but the x axis is held rigid by the smooth rods.

 

Golly that's an awfully personal question...

My printer's smooth rods both for Z and X are quite stiff, with no wobble in the rods themselves - only in the black plastic piece they attach to (which is minimal). Though the threaded rods do have that significant wobble, there isn't much X/Y wobble of the head itself because of the rigidity of the Z smooth rods.

Just seems odd that they have so much play in them, and that the... thicker bit at the bottom of the right threaded rod (is that the compression coupling? ~ 3cm diameter shiny metal cylinder with a slit on top and some on the sides, that the threaded rod sits on/in) is sorta springy when I push down on the threaded rod on the Z axis, while the one on the left is firm and doesn't budge.

I'm looking to do some very very fine detail prints for some production prototypes, and just trying to eliminate every variable that might cause imperfections.

 

I've mentioned the compression in the threaded rod couplings earlier.

I believe there is an instruction on how to fix it here on the forums. Check posts by me and I think you might find it.

If I remember correctly One basically loosen the set screw in the coupling and then pull the coupling up while pressing the rod down and the tightening the set screw again. But you probably want to double check that.

When it comes to the wobbling in the threaded rods I see the same thing on my printer. Don't know if it affects anything or how to fix it tho.

Regards, Daniel

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Yay, fixed the coupling! It was as simple as you said, da9l. Loosened the screw, got everything realigned, and tightened the screws back up and now it's rock solid. Makes me wonder how it got installed "mushy" in the first place when it almost "wanted" to be in the right position and I'd have had to force it to be aligned in the odd springy way it was done in the first place.

Also, this may be a good thing to suggest to people who still have problems throwing their nuts, especially as my springy coupling was on the right side which made it much more difficult to dial in the correct z-stop measurement - press down on the screw to turn it and it'd press down onto the z-stop, stop screwing and it'd spring back up.

Still got the wobble in the threaded rods, but as I'm not actually seeing much actual X/Y wobble in prints, I guess I won't worry about it too much, though I might see about designing a thing to attach the top of the smooth rod to the threaded rod but still allow it room to turn, just to give it that extra bit of stabilization/rigidity.