The minimum allowable bare steel thicknesses and their mil designators are as follows: 25 Gage - .0179" = 18 mil 22 Gage - .0269" = 27 mil 20 Gage - .0329" = 33 mil 18 Gage - .0428" = 43 mil 16 Gage - .0538" = 54 mil ... " p4 @5 [+ w* j8 Q: V) d 3 s$ L! X Z$ n7 C18 gage steel 也就是43 mil 规格的钢。mil 千分之一寸。