FORD WA 971 PDF

1. SCOPE.

This standard covers tie dimensions, material and physical properties, and performance requirements of through hardened and carbon restored trilobular screws with a special configuration at the crest of the threads which for Ford purposes shall be known as a "CREST INTERFERENCE" thread. I As partial or complete decarburization of the thread form seriously impairs the locking properties of the screw, this condition is not pezmitted. Decarburization as permitted by IS0 898/l is replaced in this standard by a requirement for carbon restoration as detailed in Clause 3.2. NOTE: These screws are designed to be used in normal IS0 metric threaded holes in the range M6 to Ml2 inclusive. I_ 1 REFERENCE. WSD-M lA284-B -Steel screws and bolts, surface hardened 1000 N/mm* tensile strength. 7 -. DIMENSIONS. The dimensions of the Crest Interference thread shall be as specified in Figure 1 and Table 1 prior to application of a protective coating. Parts already coated shall be