Note: This video is for the previous-generation HCD-1501. However, the principles of loosening the hook, re-timing and setting the gap are the same. Be sure on re-tightening the 3 screws on the neck of the rotary hook that the hook does not shift position. Hint: when re-tightening the sets screws, tighten gently at first, re-check [...]
Needle Diagram - closeup anatomy of a needle and its proper orientation when installed in the embroidery machine.