doverfarm

If all of your thread problems are in the shuttle area( below the plate) then the issue is the timing. Try lowing the needle to the lowest position and then raise about 3/16 of an inch then look and see where the shuttle hook is in relation to the needle. You may have to loosen a nut on the lower shaft and set(rotate) your shuttle hook next to your needle and then re tighten lower shaft nut. Rotate and check. It may take a few times to fine tune it. Good luck.