Slow x Gantry "grinding" noise

[Matt_Sharkey]

I recently upgraded to the V4, after this the x gantry makes a pretty loud noise when it moves at slow speeds. While I was replacing the V4 I also
-cleaned the x linear rail with WD40, wiped clean
-applied 3 in 1 oil on top of the rail and lithium in the grove
-removed and cleaned the X linear Bearing.
-3 in 1 oil on the linear bearing and wiped dry.

I had suspected when I removed the linear bearing that I either lost a ball, or messed it up in some way, so I ordered a new one and installed it "properly."

it still grinds. help!

EDIT: Video link: https://youtu.be/Sngk6a0vGz8
and another: https://youtu.be/yHsFsB8nYxk
Third time? https://youtu.be/lwlubu9Uu2E

EDIT: End result found here: viewtopic.php?f=7&t=3770&start=10#p27358

[sthone]

Only thing that comes to mind (if this is even possible) is when you screwed the V4 mount to the carriage maybe you used too long of a screw and it's poking through and hitting the rail?

[Jules]

Video of the noise would be good, and some close ups of the print head movement.

My total guess (without seeing/hearing it) would be that one of the tiny nuts underneath the belt clamp fell out, and it might be getting pushed around. (I wound up taping them into place before installing - little suckers were always making a break for it.)

[Matt_Sharkey]

Here is the video: https://youtu.be/Sngk6a0vGz8

I printed a bar test which is aligned along the y axis to show that the grinding doesn't happen with Y moves. While it "prints" the Skirt it will grind.

[Jules]

Flip it around along the X-axis so we can hear more of the grinding - does it stop when the bed fan kicks on? (Sounds like something is knocking on the fan.)

[Matt_Sharkey]

Another video per jules request https://youtu.be/yHsFsB8nYxk

[Mach]

Mine makes the same noise. I'd love to know what is causing this.

[Jules]

I've watched that five times, and I have no idea.

It only does the grinding when it's trying to extrude though, so it's probably not something dragging on the rail.

Don't know guys....needs someone with more mechanical savvy than me!

[Matt_Sharkey]

Why not another video! If not to just get more attention.

https://youtu.be/lwlubu9Uu2E

[Jules]

Actually, I thought i heard it when it wasn't extruding that time - if the guys don't pop in with the definitive answer here, I'd start disassembling - one part at a time, and move the print head with the jog controls until I could pinpoint it. (It might be the fallen nut or the screw dragging or that fan shroud hitting the fan.) What's the tension like on that belt? Twangy or thunky?