Compared to motor springs, spiral springs have a distance between the coils and are suitable for a smaller number of turns. Correctly mounted, the springs work without friction. The standard springs are made of stainless-steel strip with rounded edges for an optimum lifetime. At the maximum angle of rotation, the lifetime is a maximum of 10 000 cycles. At 80% of the permissible angle of rotation, the lifetime increases to 100 000 cycles. The tolerances for the positions between the inner and outer end are ±10 degrees for springs with 5 coils, or ±15 degrees for springs with 8 coils.