An overlock machine is also called a serger. It is a type of sewing machine that is used to finish seams so they don't fray and to hem the ends of a garment or another project. As the overlocker works, it has knives that cut off any excess fabric. In most cases the knives can be retracted if you want. After every few projects, you need to service your overlock machine to keep it in good working condition.
Turn off the overlocker and unplug it from the power source. Open the overlocker and brush out any lint or fabric debris with the brush to clean out the interior of the machine. Wipe the machine with the cotton cloth.
Place two to three drops of oil on the metal parts of the overlocker that need oiling. Consult your user manual to see which parts need oiling, as each overlock machine is different.
Remove the old needles from your overlocker and replace them with new needles. Push the needles all the way up into the needle holder and tighten the holder on the needles to hold them in place.
Remove the old upper and lower knives from your overlocker. Use a screwdriver to remove them. Place the new knives in the upper and lower knife positions and screw them in place.