Bad vibrations; is it in my head?

[spro]

The carriage feed is timed to the motor drive. The "pattern" is telling you something. Is it interrupted or continuous?

[liveaboard]

It was the head bearings, they were too tight.
All other possibilities suggested were checked, most before the first post.

[spro]

I thought the issue was resolved to satisfaction. I was replying to KJ . Sometimes people insert themselves into an active thread because great folks are there, thinking about the same issue. We always learn something. That particular mention of the chromium flaking off the rollers, is golden.