Hello, I'm from the Korean singer slotting machine manufacturer? There are several reasons why the qualifying lines are not in line.

Treatment of unstable tool rest: fix the screws around the tool rest but not too tight, so that the tool rest will not go down.

The tool rest is not in a straight line. Solution: realign and put them one by one. After all tool heads enter the stainless steel plate, press the tool holder upward. Will there be wires on the sheets? According to that line, you can know which knife is crooked and adjust it.