The definition of duty of care

Tap Size Pitch Tapping Drill mm M2 0.4 1.6 M2.5 0.45 2.05 M3 0.5 2.5 M3.5 0.6 2.9 M4 0.7 3.3 M4.5 0.75 3.7 M5 0.8 4.2 M6 1.0 5.0 M7 1.0 6.0 M8 1.25 6.8 M9 1.25 7.8 M10 1.5 8.5 M11 1.5 9.5 M12 1.75 10.2 M14 2.0 12.0 M16 2.0 14.0 M18 2.5 15.5 M20 2.5 17.5 M22 2.5 19.5 M24 3.0 21.0 M27 3.0 24.0 M30 3.5 26.5 M33 3.5 29.5 M36 4.0 32.0 M39 4.0 35.0 M42 4.5 37.5 M45 4.5 40.5 M48 5.0 43.0 M52 5.0 47.0 ISO METRIC (Coarse) METRIC (Fine) Tap Size Pitch Tapping Drill mm M8 1.0 7.0 M10 1.25 8.8 M12 1.25 10.8 M12 1.5 10.5 M14 1.5 12.5 M16* 1.5 14.5 M18 1.5 16.5 M20* 1.5 18.5 M22 1.5 20.5 M24 2.0 22.0 * METRIC CONDUIT UNC (Unified National Coarse) Tap Size T.P.I. Tapping Drill mm 3(.099) 48 2.0 4(.112) 40 2.25 5(.125) 40 2.6 6(.138) 32 2.75 8(.164) 32 3.4 10(.190) 24 4.1 12(.216) 24 4.4 1/4 20 5.1 5/16 18 6.6 3/8 16 8.0 7/16 14 9.4 1/2 13 10.8 9/16 12 12.2 5/8 11 13.5 3/4 10 16.5 7/8 9 19.5 1” 8 22.0 1-1/8 7 25.0 1-1/4 7 28.0 1-1/2 6 34.0 UNF (Unified National Fine) Tap Size T.P.I. Tapping Drill mm 3(.099) 56 2.1 4(.112) 48 2.35 5(.125) 44 2.65 6(.138) 40 2.9 8(.164) 36 3.5 10(.190) 32 4.1 12(.216) 28 4.6 3/16* 32 4.0 1/4 28 5.5 5/16 24 6.9 3/8 24 8.5 7/16 20 9.8 1/2 20 11.5 9/16 18 12.8 5/8 18 14.5 3/4 16 17.5 7/8 14 20.5 1” 12 23.5 1”* 14 24.0 1-1/8 12 26.5 1-1/4 12 29.5 1-1/2 12 36.0 * UNS BSW (British Standard Whit) Tap Size T.P.I. Tapping Drill mm *3/32 48 1.9 1/8 40 2.55 *5/32 32 3.2 3/16 24 3.7 *7/32 24 4.5 1/4 20 5.1 5/16 18 6.5 3/8 16 8.0 7/16 14 9.3 1/2 12 10.5 9/16 12 12.2 5/8 11 13.5 3/4 10 16.5 7/8 9 19.5 1” 8 22.0 1-1/8 7 25.0 1-1/4 7 28.0 1-1/2 6 34.0 1-3/4 5 39.0 2” 4-1/2 45.0 * WHIT FORM BSF (British Standard Fine) Tap Size T.P.I. Tapping Drill mm 3/16 32 4.0 1/4 26 5.4 5/16 22 6.8 3/8 20 8.3 7/16 18 9.8 1/2 16 11.0 9/16 16 12.7 5/8 14 14.0 3/4 12 16.5 7/8 11 19.5 1” 10 22.5 1-1/8 9 25.5 1-1/4 9 29.0 1-1/2 8 34.5 1-3/4 7 40.5 SPARK PLUG Tap Size Pitch Tapping Drill mm M10 1.0 9.0 M12 1.25 10.8 M14 1.25 12.8 M18 1.5 16.5 BSPT ISO Rc Taper Series Tap Size Pitch Tapping Drill mm Rc1/8 28 8.2 Rc1/4 19 10.8 Rc3/8 19 14.5 Rc1/2 14 17.5 Rc3/4 14 23.0 Rc 1” 11 29.5 Rc1-1/4 11 38.0 Rc1-1/2 11 43.5 Rc 2” 11 55.0 BSPF ISO G Parallel Series Tap Size Pitch Tapping Drill mm G1/8 28 8.8 G1/4 19 11.8 G3/8 19 15.5 G1/2 14 19.0 G5/8 14 21.0 G3/4 14 24.5 G7/8 14 28.5 G 1” 11 31.0 G1-1/4 11 40.0 G1-1/2 11 45.5 G1-3/4 11 51.5 G 2” 11 57.0 NPSF (Straight) DRYSEAL Tap Size Pitch Tapping Drill mm 1/8 27 8.5 1/4 18 11.0 3/8 18 14.5 1/2 14 18.0 NPTF (Taper) DRYSEAL Tap Size Pitch Tapping Drill mm 1/8 27 8.4 1/4 18 11.0 3/8 18 14.5 1/2 14 17.5 3/4 14 23.0 1” 11-1/2 29.0 1-1/4 11-1/2 37.5 Always wear eye protection when using cutting tools. Taper pipe threads of improved quality are obtained when taper is pre-formed. “The tapping drill sizes indicated are recommended only and should give approximately 75% of thread depth”. TAPPING DRILL SIZES To Convert Multiply by Inches to Millimetres 25.4 Inches to Centimetres 2.54 Inches to Metres 0.0254 Feet to Millimetres 304.8 Feet to Centimetres 30.48 Feet to Metres 0.3048 Yards to Metres 0.9144 Fathoms to Metres 1.8288 Chains to Metres 20.1168 Furlongs to Metres 201.168 Miles to Kilometres 1.609344 LENGTH lbf/in2 = kPa kPa = lbf/in225 = 172.36 155 = 22.48 26 = 179.26 160 = 23.20 27 = 186.16 165 = 23.93 28 = 193.05 170 = 24.66 29 = 199.95 175 = 25.38 30 = 206.84 180 = 26.11 31 = 213.74 185 = 26.83 32 = 220.63 190 = 27.56 33 = 227.53 195 = 26.28 34 = 234.42 200 = 29.00 35 = 241.31 205 = 29.73 TYRE PRESSURE POWER To Convert Multiply by Foot pounds-force per second into watts 1.35582 Horsepower into watts 745.7 Foot pounds-force per second into kilowatts 0.001356 Horsepower into kilowatts 0.7457 Horsepower into metric horsepower 1.01387