Rough HG15 linear rails

[earnest acorn]

I am assembling my vcore 4. I am preparing the HG15 z rails, however two out of three of the rails are rough throughout their full range of motion. I've tried to demonstrate this in the video.

I have disassembled the rails and confirmed each has the correct number of ball bearings in all four channels. The ball bearings themselves all move smoothly in their channels.

I have applied three in one oil directly to the ball bearings, loosened end caps and tapped with a mallet, as per troubleshooting steps.

They don't fully bind at any point when pressure is applied, but are noisier and rougher in motion than the smooth rail, which feels very smooth.

Given they are z axis and slow moving, my feeling is that they will probably be ok. But I just wanted to check before proceeding further to see if anyone can offer advice including whether I should get in touch with Rat Rig.

Thanks

[rancid plover]

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[clear dirge]

Did you clean out the stock grease that was in them? Mine were a little rough like that but I cleaned them out really well and then used Mobilux EP2 grease on them. They are smooth but don't move fast as EP2 is a little thick, but for Z it works great.

[earnest acorn]

No I didn't, but thanks for the suggestion. I did a few more rounds of tapping with a hammer and they have loosened up a little. But I think I'll give them a proper clean out and grease. Thanks!

[frosty owl]

if you apply slight downward pressure to them they should become more smooth?

[novel glen]

I had the same issue with my rails. Disassembled them completely (took the balls out), cleaned in ultrasonic and regreased with Krytox 205. Helped a bit, but they are still junky. Not entirely happy about the rails, but I do not know whether they will affect printing.