Threading Technology – Clamping Technology 520

150 Machine Taps UNC UNF UNEF UN-8 M MF NPSF Rp (BSPP) G NPT NPTF Rc (BSPT) STI SELF-LOCK Accessories NPSM/NPSC Tech. Info v c Product Finder Class 1B 1B Tap 2B Tap 3B Tap Basis Class 2B Class 3B UNC Thread Tap Limit 3B (Tap) 2B (Tap) No. 1 - 64 H1 / H2 H2 / H3 No. 2 - 56 H1 / H2 H2 / H3 No. 3 - 48 H1 / H2 H2 / H3 No. 4 - 40 H2 H2 / H3 No. 5 - 40 H2 H2 / H3 No. 6 - 32 H2 H3 / H4 No. 8 - 32 H2 H3 / H4 No. 10 - 24 H2 / H3 H3 / H4 No. 12 - 24 H2 / H3 H3 / H4 1 / 4 - 20 H3 H4 / H5 5 / 16 - 18 H3 H4 / H5 3 / 8 - 16 H3 / H4 H4 / H5 7 / 16 - 14 H3 / H4 H4 / H5 1 / 2 - 13 H4 H5 / H6 9 / 16 - 12 H4 H5 / H6 5 / 8 - 11 H4 H5 / H6 3 / 4 - 10 H4 / H5 H6 / H7 7 / 8 - 9 H4 / H5 H6 / H7 1 - 8 H5 H6 / H7 1 1 / 8 - 7 H5 H7 / H8 1 1 / 4 - 7 H5 / H6 H7 / H8 1 3 / 8 - 6 H6 H7 / H8 1 1 / 2 - 6 H6 H7 / H8 1 3 / 4 - 5 H6 / H7 H8 / H9 2 - 4 1 / 2 H7 H8 / H9 UNF Thread Tap Limit 3B (Tap) 2B (Tap) No. 0 - 80 H1 H1 / H2 No. 1 - 72 H1 / H2 H2 / H3 No. 2 - 64 H1 / H2 H2 / H3 No. 3 - 56 H1 / H2 H2 / H3 No. 4 - 48 H2 H2 / H3 No. 5 - 44 H2 H2 / H3 No. 6 - 40 H2 H2 / H3 No. 8 - 36 H2 H2 / H3 No. 10 - 32 H2 H2 / H3 No. 12 - 28 H2 / H3 H3 / H4 1 / 4 - 28 H2 / H3 H3 / H4 5 / 16 - 24 H3 H3 / H4 3 / 8 - 24 H3 H3 / H4 7 / 16 - 20 H3 H4 / H5 1 / 2 - 20 H3 H4 / H5 9 / 16 - 18 H3 / H4 H4 / H5 5 / 8 - 18 H3 / H4 H5 / H6 3 / 4 - 16 H4 H5 / H6 7 / 8 - 14 H4 H5 / H6 1 - 12 H4 / H5 H5 / H6 1 1 / 8 - 12 H4 / H5 H6 / H7 1 1 / 4 - 12 H4 / H5 H6 / H7 1 3 / 8 - 12 H4 / H5 H6 / H7 1 1 / 2 - 12 H4 / H5 H6 / H7 1.11 Tolerance chart – UNC/UNF EMUGE has determined that the tolerance of the tap should be manufactured as close as possible to the finished internal thread tolerance. This practice ensures that the threads produced will comply to the gage tolerances providing that the working conditions such as machine, chucking tools, and workpiece match the application. EMUGE taps are marked with the appropriate tolerance class for their intended use. The U.S. GH thread class numbers are not marked on the tap. Tolerances for the various GH numbers are shown in the chart opposite. Classification for the tolerance 1B can be provided upon request. Taps for cast iron and titanium tapping are designed one GH class higher to provide better tool life.