■ for Unified Threads

Unit:mm Minor diameter of internal threads (D1) Bored hole size Minor diameter of internal threads (D1) Bored hole size Size Size

Max.Min.( ref.)Max.Min.( ref.)
No. 0 - 80UNF1.3051.1821.275/8 - 20UN14.78214.50414.71
No. 1 - 64UNC1.5821.4251.545/8 - 24UNEF14.98614.73214.92
No. 1 - 72UNF1.6121.4741.583/4 - 10UNC16.84016.30716.7
No. 2 - 56UNC1.8711.6951.833/4 - 16UNF17.67817.32317.59
No. 2 - 64UNF1.9121.7561.873/4 - 20UNEF17.95717.67917.89
No. 3 - 48UNC2.1461.9412.097/8 - 9UNC19.76119.17719.6
No. 3 - 56UNF2.1972.0252.157/8 - 14UNF20.67520.27020.6
No. 4 - 40UNC2.3852.1572.337/8 - 20UNEF21.13220.85421.06
No. 4 - 48UNF2.4582.2712.411 - 8UNC22.60621.97122.4
No. 5 - 40UNC2.6972.4872.641 - 12UNF23.57123.11423.5
No. 5 - 44UNF2.7402.5512.691 - 14UNS23.82523.44523.7
No. 6 - 32UNC2.8952.6422.831 - 20UNEF24.30724.02924.24
No. 6 - 40UNF3.0222.8202.971 1/16 - 12UN25.14624.68925.0
No. 8 - 32UNC3.5303.3023.471 1/16 - 14UNS25.41225.03225.3
No. 8 - 36UNF3.6063.4043.561 1/8- 7UNC25.34924.63825.2
No.10 - 24UNC3.9623.6833.891 1/8- 8UN25.78125.14625.6
No.10 - 32UNF4.1653.9634.111 1/8- 12UNF26.74626.28926.6
No.12 - 24UNC4.5974.3444.531 1/8- 14UNS27.00026.62026.9
No.12 - 28UNF4.7244.4964.671 3/16 - 12UN28.32127.86428.2
No.12 - 32UNEF4.8264.6234.781 1/4- 7UNC28.52427.81328.3
1/ 4- 20UNC5.2574.9795.191 1/4- 8UN28.95628.32128.8
1/ 4- 28UNF5.5885.3605.531 1/4- 12UNF29.92129.46429.8
1/ 4- 32UNEF5.6895.4875.641 5/16 - 12UN31.49631.03931.4
5/16 - 18UNC6.7316.4016.651 3/ 8- 6UNC31.11530.35330.9
5/16 - 24UNF7.0356.7826.971 3/ 8- 8UN32.13131.49632.0
5/16 - 32UNEF7.2647.0877.221 3/ 8- 12UNF33.09632.63933.0
3/8- 16UNC8.1537.7988.061 1/2- 6UNC34.29033.52834.1
3/8- 24UNF8.6368.3828.571 1/2- 8UN35.30634.67135.1
3/8- 32UNEF8.8648.6628.811 1/2- 12UNF36.27135.81436.2
7/16 - 14UNC9.5509.1449.41 5/ 8- 5UNS36.65235.78936.4
7/16 - 20UNF10.0339.7299.961 5/ 8- 8UN38.48137.84638.3
7/16 - 24UNS10.2109.95710.151 5/ 8- 12UN39.44638.98939.3
7/16 - 28UNEF10.33710.13510.291 3/4- 5UNC39.82738.96439.6
1/ 2- 13UNC11.02310.59210.91 3/4- 8UN41.65641.02141.5
1/ 2- 20UNF11.60711.32911.541 3/4- 12UN42.62142.16442.5
1/ 2- 24UNS11.81111.55711.751 7/8- 8UN44.83144.19644.7
1/ 2- 28UNEF11.93811.71011.881 7/8- 12UN45.79645.33945.7
1/ 2- 32UN12.03911.83711.992- 4 1/2UNC45.59344.67945.4
9/16 - 12UNC12.44611.98912.32- 8UN48.00647.37147.8
9/16 - 18UNF13.08112.75113.002- 12UN48.97148.51448.9
9/16 - 20UN13.20812.90413.132 1/4- 8UN54.35653.72154.2
9/16 - 24UNEF13.38513.13213.322 1/2- 8UN60.70660.07160.5
5/ 8- 11UNC13.86813.38613.72 3/4- 8UN67.05666.42166.9
5/ 8- 18UNF14.68114.35114.603- 8UN73.40672.77173.2
  • The recommended tap drill sizes indicated above are for JIS Class 2B UNC & UNF threads, and ANSI B1.1 Class 2B UNEF, UN & UNS threads.

Technical Inf