FORD WD950 APPENDIX A PDF

1. SCOPE.

This appendix covers the requirements for Thread Cutting Screws not specified in the body of WD 950. Unless otherwise specified all other requirements of WD 950 apply.

1.1 REFERENCES. IS0 1502 -General purpose metric screw threads -Gauging. 7 -. MATERIAL. Screws shall be made from cold heading quality, killed steel wire suitable for case hardening.   3. METALLURGICAL REQUIREMENTS. 3.1 CORE HARDNESS, SURFACE HARDNESS AND MICROSTRUCTURE. These shall be specified in Clauses 3.1,3.2 and 3.4 of the specification. 3.2 TOTAL CASE DEPTH. A microhardness test shall be carried out at the thread flank mid-point between crest and root or. in the case of smaller screws up to (M) 4, in the root of the thread. The case depth shall be at the point where the hardness exceeds the actual core hardness by I-IV25 and shall be in accordance with the following:   4. PERFORMANCE REQUIREMENTS. 4.1 DRIVE TEST. Thread cutting screws shall meet the same thread forming requir