Suddenly, a new feature appears :( The y-axis is nice and smooth but the x-axis is vibrating when it moves. It vibrates so hard that it seems to lose steps. Here's a print where the next layer is shifted over to the left a bit.
Sent these to Raise3D. Let's see if there are some adjustments I can make to get rid of the vibration.
Update: After a day of working with Raise3D, no progress with anything we tried. Everything seems good, nothing loose, broken, wobbly, shaky, or out of alignment except one of the screws on one of the bushings is stripped and wouldn't tighten. Replaced, still no good.
Thinking back, when my friend helped me set this printer up, and we tried the first print, he did notice a vibration in the x-axis, but I didn't pay attention because the print seemed to be going okay. I thought maybe it was normal. Clearly not.
The next day, I got some grease. Not SuperLube (PTFE grease), which is THE grease to have, but unfortunately because it's so good, nobody stocks it.
Instead I got some silicone grease. It seems thick, but in any case I liberally coated the rods and packed the bearings where they meet the rods, and... no vibrations! The printer is really quiet now.
Trying a small print now, and will follow up with a larger 15-hour job to see how this stuff holds up. Will also replace this grease with SuperLube once I get it in.