On the rail side of my LR3, the Z t8 screw seems to bind up which then makes the gantry tilted. This basically happens close to Z min.
It just started doing this. I am not 100% sure why. Checked all my screws, they were tight. The T8 screw nut was lose so I tightened that a bit but still will bind while doing a job.
I was going to carve out my LR4 struts on the LR3 before I dismantle it but I dont think it will reliably cut them out because of this…
I might just print the temp struts for LR4 and disassemble the LR3 anyway and go from there but I am wondering if I am missing something that wont be easy to fix once the Z is mounted in the LR4.
okay, I will give it a whirl! Thanks for the suggestion. I did for sure notice now that you mention it that the rail side was definitely a little more work to run up and down manually with the steppers disabled!
Note that this may not be the issue, so try lubing your lead screws and making sure everything is properly aligned before concluding that the rail bearings are the problem.
I don’t have a link, but what you are aiming for is to clear any debris from the small roller bearings, as well as from the small groove that the bearings slide along.
You don’t have to remove the block from the rail, just flush thoroughly with a solvent (WD40 spray or IPA liquid). You can also blow the parts dry afterwards with compressed air, which will also help to dislodge and remove any debris.
Flushing with a solvent will loosen and remove any debris, but will also remove any lubrication, so applying a light machine oil or grease to the bearings is highly recommended afterwards. Not too much, you don’t want to create a sticky surface for more debris to collect on.
I lubed the lead screws and did an up-down cycle. seemed to run a little smoother but I did notice the YZ plates were flexing left and right a little as I was going up and down.
I am going to take the cnc apart anyway to do the LR4 upgrade and I will do this for the bearings when I get them apart.
Just make sure to not slide the block off the rail when you disassemble the Lowrider, the little ball bearings have a habit of disappearing on your shop floor…
That is a bit funky, for sure. Can you take a longer video with just an upward movement (try homing Z).
It kind of looks like the plastic stub is rubbing against the YZ plate on the left side.
What happens if you rotate the lead screw by hand (turn off the power, otherwise the holding current will prevent it from moving). You should be able to rotate the screw such that the ganty lifts to the top of the travel. (Don’t try to lift by the plastic stub, as you may stretch the coupler). If there is binding, then there is probably either an alignment issue or the linear rail is binding. If it moves freely, then you probably have a wiring or motor issue.
Another thing to try, seeing that you are disassembling it anyways, is to remove the bottom two grub screws, and lift the gantry. Again this can tell you if the rails are sticking.
