1. After pressing a needle bar (let the black drive block hang on the needle bar), shake the needle bar up and down. If there is already a distance of 5MM, remove the machine head to check whether the gap of the black drive block becomes larger, three eyes Connecting rod, No. 1 pin, No. 2 pin, small connecting rod. Dalian rods generally don't have too much clearance. If they are too big, hey, please remove the shaft, it's enough for you.
2. Open the needle plate, press a needle bar (let the black drive block hang the needle bar), turn the upper shaft (don't look at the scale-important) first check the tightness of the chain, loosen the hook, look carefully with your eyes, Do not turn the upper shaft after confirming the bottom dead center of the needle bar. At this time, adjust the rotary hook, look over from the back of the needle, and let the right edge of the three small Roses on the right side of the quasi-rotary hook (remember to face the needle bar), fix the rotary hook, then adjust it below Just click the shuttle and the needle bar.
3. Sometimes it is necessary to check whether the free stroke of the thread take-up lever becomes larger

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