How to adjust the air pump presser foot of ZOJE four-line car?

There is a screw behind the fart drum of the folding presser foot. Tighten it slightly, and then turn the adjusting needle to the maximum state.

The needle pitch of sewing machine has a needle dial, on which 1-*MM will be clearly written, which can be independently rotated and adjusted. Conventional sewing machines all have a needle dial, which can be adjusted by rotation, and some machines need to press the needle handle backwards to adjust. If the needle distance button and needle of the sewing machine have been adjusted to the maximum, but the needle distance is still small, check whether the feed teeth are too low, and adjust the height of the feed teeth and the tightness of the presser foot appropriately. When the side cover is opened, there is a needle code adjustment button on the front. When the button is stuck in the slot, the handwheel rotates forward to increase the needle size, and vice versa.