Included in this SAE Standard are the detailed general and dimensional specifications applicable to flanged 12-point screws recognized as SAE Standard and intended for general use in automotive and other ground-based vehicles and industrial equipment.
The inclusion of dimensional data in this standard is not intended to imply that all of the products described are stock production sizes. Consumers should consult manufacturers concerning availability of product.
Change in 3.1 regarding dimensions applying to unplated and uncoated product made for clarity. Combined and modified Section 3.3.3 and Section 3.3.4, to incorporate two-ring gage acceptability for screw heads, similar to metric 12 Point Flange Screw Standards. Modified Figure 1 and Table 1 accordingly. Added Table 1A.
Added section 3.3.5 as specification lacked requirements for head position.
Section 3.4, Figure 1, and Table 1: changed method of dimensioning fillet for ease of interpretation. The values for Ea were calculated from the previous dimensioning method (E min+2*M min, etc.) so that the part requirements have not physically changed. Only the dimensioning method has changed. Language in section 3.4 made similar to ASME B18.104.22.168M (hex flange screws) for fillet form.
Section 3.4 2nd paragraph modified as this standard does not cover reduced body diameters.
Revised 3.7 to clarify thread dimensional requirements and include constant pitch thread series as a purchaser option. Also made 2A the default uncoated/unplated thread class if not otherwise specified.
Modified section 3.11 to better title the gage method as straightness inspection only. Eliminated Appendix A in favor of straightness gaging per ASME B18.2.9, which better reflects industry practice. Straightness tolerances were listed per previous Appendix A requirements and added graduated requirements for longer screws.
Changes to 3.12 made to reference other industry standards for additional material options. Added cautionary statement regarding hydrogen embrittlement and specifications exceeding HRC 39 hardness. Added discontinuity and decarburization requirements to section 3.14 to better define workmanship.