This document specifies the grades, benchmarks, measurements, tolerance values and drawing marks of the geometric accuracy of rack teeth (hereinafter referred to as "rack accuracy"). This document applies to single straight or helical racks whose basic tooth profile conforms to GB/T1356, whose normal modulus mn ranges from 1 mm to 40 mm, and whose working tooth width b is not greater than 630 mm. Warning: users of this document should be aware that the accuracy value of the unassembled rack cannot be used to directly judge the performance of the assembled rack pair.