The weight applied during coiling is important
and is adjustable over a narrow range for a
given fiber: Too little weight and the fiber snarls
during twist insertion; too much weight and the
fiber breaks. For example, the load during coiling
can be varied between 10 and 35 MPa for a
127-mm-diameter nylon 6,6 sewing thread, yielding
coils with spring indices between 1.7 and 1.1,