Cutex Brand Sewing Machine Snip Grip Thread Cutter With Concealed Knife Sewing Machine Snip Grip Thread Cutter With Concealed Knife. Simply attach it to the presser foot bar with same screw that holds presser foot. It will not interfere with normal sewing; but can be used when needed. Spring holds thread, preventing the needle from becoming unthreaded. Concealed knife cuts the thread. Eliminates : Needle rethreading, picking up scissors to cut thread and bunching of thread at next operation. Cuts down on thread waste, breakage of needles and labor costs.