This guide is for the Butterfly multihead knife trimmer adjustment. Adjusting the knife stop position will help give you longer or shorter trim lengths. Not having the knives set at the correct position can cause trimming issues.
To access the knives, you must remove the needle plate. Once you remove the needle plate, you will see both the fixed and movable knives. The fixed knife is the smaller one and the movable knife is the larger one that slides underneath. The movable knife does not cut but instead helps guide and pull the thread under the upper knife, which is the blade end. This guide is for adjusting the multihead movable knife. Adjusting this also changes the length of the thread when cutting. Connected to the movable knife is a rod. Follow this rod to the back of the neck of the embroidery machine. Depending on the machine model, there will be an adjusting screw that can be loosened and allow you to freely move the knife in and out by hand with the rod. With the embroidery machine off, rotate the main shaft to 290 degrees. Once the machine is at 290 degrees, you can adjust the moving knife. At 290 degrees, move the loosened rod attached to the movable knife, until the beveled tip barely is completely out. Moving this in and out a bit will make the trim stitches shorter or longer.
At 290 degrees the two blades should be slightly touching at the movable knife bevel edge. At 291 degrees, the movable will still work for example but the trim stitch left over will be a bit longer then when set at 290. The position between two blades only affects the trimming thread length. You can follow the instructions in the video by putting a wrench under the cam to adjust the starting point when it is at 290 degrees. This will hold the movable knife in place. If you want a longer trim stitch, try adjusting the movable knife at a higher degree number like 291, instead of 290. For a shorter trim stitch, position the knife when the machine is at a degree smaller then 290, like 289 for example. Setting the movable knife at 291/292 degrees make a longer trim. Setting it at 289/288 will make a shorter trim.