Общий каталог OSG 2018 - 2019 - страница 672

Tap Drill Size Tap Drill Sizes - Fractional Form Taps To minimize tapping problems and lengthen tool life, use the largest drill Suggested Percentage of Full Thread in Tapped Holes possible to produce a minor diameter that will result in the lowest percentageof full thread consistent with adequate strength. A minor diameter thatMaterial*Deep HoleAverage Thin Sheet StockTappingCommercial Workor Stamping provides a 55% to 65% thread is sufficient for most requirements, but in somecases a higher percentage of thread may be necessary to conform with theminor diameter limits of the thread class specified.Aluminum, Brass,FreeBronze, Cast Iron,CuttingCopper, Mild Steel,60% - 70%65% - 70%75% - 85% Tool Steel * Generally, deeper than 1 1/2 times the hole diameter. Hard orToughCutting Cast Steel, DropForging, Monel Metal,Nickel Steel, StainlessSteel55% - 65%60% - 70% Threads Per Inch Minor Diameter Tap Drill Diameter - Form Taps Tap Size 75% Thread 70% Thread 65% Thread 60% Thread 55% ThreadUNCUNF8-PitchMin. 2BMax. 2B (in) (in) (in) (in) (in) 0 – 80 – 0.0465 0.0514 0.0536 0.0540 0.0545 0.0549 0.0554 1 64 – – 0.0561 0.0623 0.0650 0.0655 0.0661 0.0666 0.0672–72–0.05800.06350.06590.06630.06690.06730.0679 2 56 – – 0.0667 0.0737 0.0769 0.0774 0.0781 0.0787 0.0794–64–0.06910.07520.07800.07850.07910.07960.0802 3 48 – – 0.0764 0.0845 0.0884 0.0890 0.0898 0.0905 0.0913–56–0.07970.08650.08990.09040.09110.09170.0924 4 40 – – 0.0849 0.0939 0.0993 0.1000 0.1010 0.1018 0.1028–48–0.08940.09680.10140.10200.10280.10350.1043 5 40 – – 0.0979 0.1062 0.1123 0.1130 0.1140 0.1148 0.1158–44–0.10040.10790.11340.11410.11500.11570.1166 6 32 – – 0.1040 0.1140 0.1221 0.1230 0.1243 0.1252 0.1264–40–0.11100.11900.12530.12600.12700.12780.1288 8 32 – – 0.1300 0.1390 0.1481 0.1490 0.1503 0.1512 0.1524–36–0.13400.14200.14980.15070.15180.15260.1537 10 24 – – 0.1450 0.1560 0.1688 0.1700 0.1716 0.1729 0.1746–32–0.15600.16400.17410.17500.17620.17720.1784 12 24 – – 0.1710 0.1810 0.1948 0.1960 0.1976 0.1989 0.2006–28–0.17700.18600.19780.19900.20020.20140.2028 1/4 20 – – 0.1960 0.2070 0.2245 0.2260 0.2279 0.2295 0.2315–28–0.21100.22000.23180.23290.23420.23540.2389 5/16 18 – – 0.2520 0.2650 0.2842 0.2861 0.2879 0.2898 0.2917–24–0.26700.27700.29120.29270.29410.29550.2969 3/8 16 – – 0.3070 0.3210 0.3431 0.3452 0.3474 0.3495 0.3516–24–0.33000.34000.35370.35520.35660.35800.3594 7/16 14 – – 0.3600 0.3760 0.4011 0.4035 0.4059 0.4084 0.4108–20–0.38300.39500.41200.41370.41540.41710.4188 1/2 13 – – 0.4170 0.4340 0.4608 0.4634 0.4660 0.4686 0.4712–20–0.44600.45700.47450.47620.47790.47960.4813 9/16 12 – – 0.4720 0.4900 0.5200 0.5229 0.5257 0.5285 0.5313–18–0.50200.51500.53420.53610.53790.53980.5417 5/8 11 – – 0.5270 0.5460 0.5787 0.5817 0.5848 0.5879 0.5910–18–0.56500.57800.59670.59860.60040.60230.6042 3/4 10 – – 0.6420 0.6630 0.6990 0.7024 0.7058 0.7092 0.7126–16–0.68200.69600.71810.72020.72240.72450.7266 7/8 9 – – 0.7550 0.7780 0.8183 0.8221 0.8259 0.8297 0.8334–14–0.79800.81400.83860.84100.84340.84590.8483 1 8 – – 0.8650 0.8900 0.9363 0.9405 0.9448 0.9490 0.9533–12–0.91000.92800.95750.96030.96320.96600.9866 FORMULA: TAP DRILL SIZE FORMULA: PERCENTAGE OF FULL THREAD Drill Size = Tap Major Dia - 0.0068 x % of Full Thread# of Threads Per Inch % of Full Thread = Threads Per Inch x Tap Major Dia - Drill Dia0.0068 Example: Determine Drill Size for 2”—12N Tap,70% Full Thread. Example: Determine the % of Full Thread for 2”—12N Tap, using 1.9603” Drill. Basic Major Diameter of Tap = 2.0000” Threads Per Inch = 12 0.0068 x 70 = 0.4760 ÷ 12 = 0.0397” 2.0000 - 1.9603 = 0.0397 ÷ 0.0068 = 5.838 Drill Size = 1.9603” Percentage of Full Threads = 70% Suggested Pipe Tap Drill Sizes Tap Size 1/16 1/8 1/4 3/8 1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 3-1/2 4 Drill Taper Pipe Tap* C Q 7/16 9/16 45/64 29/32 1-9/64 1-31/64 1-23/32 2-3/16 2-5/8 3-1/4 3-3/4 4-1/4 Sizes Straight Pipe Tap† 1/4 11/32 7/16 37/64 23/32 59/64 1-5/32 1-1/2 1-3/4 2-7/32 2-21/32 *Sizes given permit direct tapping without reaming the hole, but only give a full thread for the first two or three threads. †For Dryseal Straight Pipe Threads suggested drill sizes are as shown, except; 1/4” pipe, use .444 drill size. 672 Threading Technical WWW.OSGTOOL.COM