Thanks for the advice. The machine is new - I got it at the very end of 2022, and have only played on it a little until now. ( I had an HQ16 before this one, so I'm not new to quilting.) I didn't think the timing should go out without a needle break either -- but it did! And now, it won't stay timed. I've retimed, cleaned up the shaft again, and tightened screws as far as they will tighten. The hook cannot be moved manually -- however, 1-2 minutes into quilting, it somehow shifts, and the timing is once again completely off. This has happened 4 times. Jim, I don't know how you detected a burr on a screw hole! --- and how did you get in there to remove it without messing up the threads? I'd like to think something like that would fix my issues once & for all. I'll be calling the service department -- after the holiday break. Thanks again, y'all.