Are these safe and has anyone used one before Steel Leaf Spring Shims < BACK 2-6 degree, $26.95 8 degree, $30.95 Applications: These shims are CNC machined from solid steel. They can be ordered in either 2, 4, 6, or 8 degrees. The center pin hole is 5/16 diameter. It can be drilled to fit any center pin size. These shims will not break like most aluminum ones.