Symptoms of Too Advanced and Too Retarded Hook Timing

Hook Timing: Relative to what, you might ask. Predominantly relative to the actions of the take up lever. Good hook timing means: There is enough slack to go around the bobbin case The hook cast off point rotates into position before the take up lever tries to pull the thread through the cast off point The take up lever pulls the loop of thread up into a knot before the hook point double stabs the loop of thread (In short, machine runs smooth) Too-Ritarded timing means: Not enough slack in the needle thread as it rounds the bobbin case. ("thread grabby") The take up lever tries to pull the loop of thread past the cast off point before the cast off point has rotated into position, and the thread snags. (In short, the machine runs rough) Too-Advanced timing means: There is plenty of slack to go around the bobbin case (sometimes too much, such that the thread has no impetus to jump across the gate) The hook point double stabs the loop of thread before the take up lever pulls the thread up into a knot. (In short, the machine consistently jams or breaks thread)