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Bolt Nut Fastener Force Conversion Table

Unified Thread Recommended Tapping Drill and Clearance Hole Sizes

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Use these tables for calculating the relevant size drill bit and clearance hole for unified threads.

All dimensions are in millimeters (mm).

Screw SizeNo. of Threads Per InchMinor DiameterTap DrillsClearance Hole Drills - All Materials
Aluminum, Brass & Plastics 75% ThreadStainless Steel, Steels & Iron 50% ThreadClose FitFree Fit
No. or DiameterMajor DiameterDrill SizeDecimal Equiv.Drill SizeDecimal Equiv.Drill SizeDecimal Equiv.Drill SizeDecimal Equiv.
00.06800.04473/640.0469550.052520.0635500.07
10.073640.0538530.05951/160.0625480.076460.081
720.056530.0595520.0635
20.086560.0641500.07490.073430.089410.096
640.0668500.07480.076
30.099480.0734470.0785440.086370.104350.11
560.0771450.082430.089
40.112400.0813430.089410.096320.116300.1285
480.0864420.0935400.098
50.125400.0943380.10157/640.1094300.1285290.136
440.0971370.104350.11
60.138320.0997360.1065320.116270.144250.1495
80.164320.1257290.136270.144180.1695160.177
360.1299290.136260.147
100.19240.1389250.1495200.16190.19670.201
320.1517210.159180.1695
120.216240.1649160.177120.18920.22110.228
280.1722140.182100.1935
320.1777130.18590.196
1/40.25200.188770.2017/320.2188F0.257H0.266
280.206230.21310.228
320.21177/320.218810.228
5/160.3125180.2443F0.257J0.277P0.323Q0.332
240.2614I0.2729/320.2812
320.27429/320.2812L0.29
3/80.375160.29835/160.3125Q0.332W0.386X0.397
240.3239Q0.332S0.348
320.336711/320.3438T0.358
7/160.4375140.3499U0.36825/640.390629/640.453115/320.4687
200.376225/640.390613/320.4062
280.3937Y0.404Z0.413
1/20.5130.405627/640.421929/640.453133/640.515617/320.5312
200.438729/640.453115/320.4688
280.456215/320.468815/320.4688
9/160.5625120.460331/640.484433/640.515637/640.578119/320.5938
180.494333/640.515617/320.5312
240.511433/640.515617/320.5312
5/80.625110.513517/320.53129/160.562541/640.640621/320.6562
180.556837/640.578119/320.5938
240.573937/640.578119/320.5938
11/160.6875240.636441/640.640621/320.656245/640.703123/320.6562
3/40.75100.627321/320.656211/160.687549/640.765625/320.7812
160.673311/160.687545/640.7031
200.688745/640.703123/320.7188
13/160.8125200.751249/640.765625/320.781253/640.828127/320.8438
7/80.87590.738749/640.765651/640.796957/640.890629/320.9062
140.787413/160.812553/640.8281
200.813753/640.828127/320.8438
15/160.9375200.876257/640.890629/320.906261/640.953131/320.9688
1180.84667/80.87559/640.92191-1/641.01561-1/321.0313
120.897815/160.937561/640.9531
200.938761/640.953131/320.9688
1-1/161.0625180.9943111-1/641.01561-5/641.07811-3/321.0938
1-1/81.12570.949763/640.98441-1/321.03131-9/641.14061-5/321.1562
121.02281-3/641.04691-5/641.0781
181.05681-1/161.06251-5/641.0781
1-3/161.1875181.11931-1/81.1251-9/641.14061-13/641.20311-7/321.2188
1-1/41.2571.07471-7/641.10941-5/321.15621-17/641.26561-9/321.2812
121.14781-11/641.17191-13/641.2031
181.18181-3/161.18751-13/641.2031
1-5/161.3125181.24431-1/41.251-17/641.26561-21/641.32811-11/321.3438
1-3/81.37561.17051-7/321.21871-17/641.26561-25/641.39061-13/321.4062
121.27281-19/641.29691-21/641.3281
181.30681-5/161.31251-21/641.3281
1-7/161.4375181.36931-3/81.3751-25/641.39061-29/641.45311-15/321.4688
1-1/21.561.29551-11/321.34371-25/641.39061-33/641.51561-17/321.5312
121.39781-27/641.42191-7/161.4375
181.43181-7/161.43751-29/641.4531
1-9/161.5625181.49431-121.51-33/641.51561-37/641.57811-19/321.5938
1-5/81.625181.55681-9/161.56251-37/641.57811-41/641.64061-21/321.6562
1-11/161.6875181.61931-5/81.6251-41/641.64061-45/641.70311-23/321.7188
1-3/41.7551.50461-9/161.56251-5/81.6251-49/641.76591-25/321.7812

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