These brass parts are sold separately and are useful when handmade flat needles (flat shaders) from loose needles (loose needles) using the "Jig for Flat Needles. With the needles lined up on the body, you can easily slide this part to even out the tips of the needles. There are either "fan-shaped parts" for gently curving the needle line or "flat (straight) parts" for straightening the tip, so please choose the size that best suits your needs.
