① material moving irregularly: in the process of sewing the lining, sometimes uneven material velocity, short irregularities when the stitch length. Lining all by sending buyA and foot co-ordination forward transport, therefore, when materials such irregular movement, it can be concluded that, teeth and feet failed or improper pressure adjustment. II material forward: transmitted material depends on the teeth. When there is a material does not move, only found in the dental problems. If the position is too low, the material will be impossible to move forward. Adjustment with a cocked head, feed lifting rock shaft crank screw loose, then lift gently with a screwdriver, to buyA. With a needle plate on 0.8-1 mm. Is the standard size of teeth high and low, so long as adjustments to this location, material can walk normal. Finally, tighten the screws. When turning the screw. Similarly to head to pull up. ③ materials back and forth: When sewing fabric, often there will be material back and forth, which is a step forward, to take a step back. This is caused by too high due to buyA, teeth flat of the needle plate is too high, teeth are always exposed out of the needle plate reciprocating motion, resulting in material back and forth. Adjustment screw loosen the feed lifting rock shaft crank, gently press the teeth using a screwdriver down, reduce the feed teeth to the standard height, namely teeth needle plate size of 0.8-1 mm, and then tighten the crank bolt. Black-cloth back.