Technical Description of productsInformation Classes of Internal Threads and Classes of Taps 5. Comparison of PD tolerances for tap classes for American market, for Yamawa P classes and for uni ed internal thread classes.  (Comparison with SP tap) Class P1 P3 P5 Size P2 P4 P6 PD tolerance of 210 220 230 240 internal threads Basic Pitch Dia. 3B 2B P1 №2-56 UNC GH2 P class 53 70 P class oversize P1№3-48UNC ANSI 55 75 GH2 ANSI oversize P1 P2 P3 internal threads 3B №4-40 UNC internal threads 2B 60 83 GH2 GH3 GH4 GH5 P1 №5-40 UNC 63 83 GH2 Class P2 P4 P6 Size P3 P5 P7 PD tolerance of 210 220 230 240 internal threads Basic Pitch Dia. 3B 2B P2 P3 P4 №6-32 UNC 68 93 GH3 GH4 GH5 GH6 GH7 P2 P3 P4 №8-32 UNC 71 96 GH3 GH4 GH5 GH6 GH7 P2 P3 P4 №10-24 UNC 80 108 GH3 GH5 GH6 GH7 P2 №12-24 UNC 82 110 GH3 P2 P3 P4 1/4-20 UNC 90 123 GH5 GH6 GH7 P2 P3 P4 5/16-18 UNC 98 134 GH5 GH7 P2 P3 P4 3/8-16 UNC 108 144 GH5 GH7 P3 7/16-14 UNC 116 154 GH5   P3 P4 1/2-13 UNC 121 165 GH5 GH7 9/16-12 UNC 128 172 P3 P4 5/8-11 UNC 136 182 GH5 P3 P4 3/4-10 UNC 144 195 GH5 GH6 P3 7/8-9 UNC 154 207 GH6 Class P2 P4 P6 P8 Size P3 P5 P7 PD tolerance of 210 220 230 240 internal threads Basic Pitch Dia. 3B 2B P3 1-8 UNC 167 223 GH6 Technical-17