when my HQ when out of time (due to taking it off the frame and messing something up) DH adjusted the needle bar to retime it. He's done a lot of my older mechanical machines and is good friends with the dealer I bought it from (they are more of a repair shop that sells sewing machines than the other way around).
With HQ, the needlebar is the weakest link and if you really jam into something it will slip. Keeps you from breaking something else. Loosen a set screw, reset the needlebar and tighten it back up and everything was fine again.