Downloaded from https://www.everyspec.com APPENDIX C MIL-STD-31000A C.7.9.6 Datum feature symbols missing or incorrectly applied Diameter symbol not appropriate inside datum feature symbol. Only letters are permitted. Correct datum feature symbol Datum symbols must always be associated with a part surface,feature (such as a plane, cylinder, or axis) or geometric tolerance block. Datum symbols without leaders indicating their proper surfaces are errors. Datum symbols A and B are shown correctly on the left. Datum symbol B on right is incorrect. 129