Sewing machine vertical shuttle install - placing back bobbin case hook race locking ring

Placing back the vertical shuttle and this side loading bobbin on a sewing machine Top CHECK LIST reasons why the needle doesn't catch the thread or it's skipping stitches - bits of fabric trapped around the shuttle or under the feed dogs - remove shuttle, make sure you find videos showing how to place it back for your machine - bent needle - needle not fully inserted upwards or not inserted with the flat side the right way - thread passed the wrong way inside the needle eye (usually it goes from left tor right) - bobbin thread not inserted correctly into the bobbin - wrong type of needle or wrong type of bobbin - needle holder not secured at the correct position on the needle bar - usually it has a groove on the bar - bobbin case not fully inserted on the small shaft (must lock) - bobbin case ring holder not properly locked in place with the two small plastic tabs - wrong bobbin case - may not be compatible even between same brand - needle bar rotated - the needle eye is not parallel to the side of shuttle hook (loosen and rotate the needle bar, carefully not to move it vertically) - damaged tip of the shuttle hook after impact with the needle (replace the shuttle) - needle bar too low or too high https://rumble.com/v6kgx6a-needle-timing-position-and-depth-verticalside-bobbin-sewing-machine.html - needle and shuttle out of timing (not synchronized) after sewing thick/stiff materials, also check for loose screw on the gears or on the rod connected to the gears https://rumble.com/v6kgx6a-needle-timing-position-and-depth-verticalside-bobbin-sewing-machine.html - damage to the gears actuating the shuttle - bobbin case and shuttle laterally misaligned - hook passes too far from the needle sideways - the part keeping the hook is secured on its rod with 1-2 screws, loosen them and move the piece a little along the shaft - both the bobbin and the needle thread must be left hanging free (no tension) - presser foot must be lifted - handwheel is usually rotated by hand with top of the wheel coming towards you