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Tap Sizes

Tap Sizes and Hole Sizes


Standard Tap pre-drill sizes
Standard Metric
Tap Sizes Pre-tap Tap sizes Pre-tap
2-56 .070 M2 X .4 .063
4-40 .089 M2.5 X .45 .081
6-32 .109 M3 X .5 .098
8-32 .136 M4 X .7 .128
10-32 .161 M5 X .8 .166
10-24 .147 M6 X 1 .196
1/4-20 .203 M8 X 1.25 .265
1/4-28 .214 M10 X1.5 .332
5/16-18 .257 M12 X 1.75 .404
5/16-24 .272 M14 X 2 .469
3/8-16 .312 M16 X 2 .547
3/8-24 .332    

Roll Form Tap pre-drill sizes
Standard Metric
Tap Sizes Pre-tap Tap sizes Pre-tap
2-56 .078 M2 X .4 .072
4-40 .101 M2.5 X .45 .090
6-32 .125 M3 X .5 .110
8-32 .150 M4 X .7 .144
10-32 .175 M5 X .8 .183
10-24 .172
1/4-20 .218