Slice narrow piece of fabric

For example, with stitched buttonholes or narrow pockets, in which a zipper is to be incorporated, one must cut the fabric lengthwise.

Here are two tips

Lay thin fabrics on a hard surface and now the back of long Use part of a thread separator: Use this blunt side (corresponds to the shape of a knife back side) to move along the desired cutting line and press firmly. This softens the fabric and allows it to be cut in and then cut open as usual with a cutting knife.
For very thick, solid fabrics or those where the surface is backed with strong fleece, this does not work. Even the insertion of scissors may not lead to success or the scissors will slip off and that's it. But now comes: Take the desired piece of cloth in your hand, fold it lengthwise at an arbitrary point, cut it with scissors about 1 cm (!), Unfold it again and cut it to the final length with the thread cutter or a pair of scissors - voilà!