Recommended Tapping Drill Size

ISO Metric Coarse

Size (mm)Pitch (mm)Drill (mm)
M1.25.75
M1.1.25.85
M1.2.25.95
M1.4.31.1
M1.6.351.25
M1.8.351.45
M2.41.6
M2.2.451.75
M2.5.452.05
M3.52.5
M3.5.62.9
M4.73.3
M4.5.753.75
M5.84.2
M615
M716
M81.256.75
M91.257.75
M101.58.5
M111.59.5
M121.7510.2
M14212
M16214
M182.515.5
M202.517.5
M222.519.5
M24321
M27324
M303.526.5
M333.529.5
M36432
M39435
M424.537.5
M454.540.5
M48543
M52547
M565.550.5
M605.554.5
M64658
M68662
M72666
M76670

UNC

Size No.
or inch
Pitch
TPI
Drill (mm)
#1641.55
#2561.85
#3482.1
#4402.35
#5402.65
#6322.85
#8323.5
#10243.9
#12244.5
1/4205.1
5/16186.6
3/8168
7/16149.4
1/21310.8
9/161212.2
5/81113.5
3/41016.5
7/8919.5
1822.25
1 1/8725
1 1/4728
1 3/8630.75
1 1/2634
1 3/4539.5
24.545
2 1/44.551.5
2 1/2457.25
2 3/4463.5
3470

UNF

Size No.
or inch
Pitch
TPI
Drill (mm)
#0801.25
#1721.55
#2641.9
#3562.15
#4482.4
#5442.7
#6402.95
#8363.5
#10324.1
#12284.7
1/4285.5
5/16246.9
3/8248.5
7/16209.9
1/22011.5
9/161812.9
5/81814.5
3/41617.5
7/81420.4
11223.25
1 1/81226.5
1 1/41229.5
1 3/81232.75
1 1/21236

 

ISO Metric Fine

Size (mm)Pitch (mm)Drill (mm)
M2.251.75
M2.2.251.95
M2.3.252.05
M2.5.352.15
M2.6.352.25
M3.352.65
M3.5.353.15
M4.353.65
M4.53.5
M5.354.65
M5.54.5
M5.754.25
M5.5.55
M6.55.5
M6.755.25
M7.756.25
M8.57.5
M8.757.25
M817
M9.758.25
M918
M10.59.5
M10.759.25
M1019
M101.258.75
M11.7510.25
M11110
M111.259.75
M12.511.5
M12.7511.25
M12111
M121.2510.75
M121.510.5
M14113
M141.2512.75
M141.512.5
M15.7514.25
M15114
M151.513.5
M16.515.5
M16.7515.25
M16115
M161.2514.75
M161.514.5
M17116
M171.515.5
M18.7517.25
M18117
M181.2516.75
M181.516.5
M18216
M19118
M20119
M201.518.5
M20218
M22121
M221.520.5
M22220
M24123
M241.522.5
M24222
M25124
M251.523.5
M25223
M27126
M271.525.5
M27225
M28127
M281.526.5
M28226
M30129
M301.528.5
M30228
M30327
M32131
M321.530.5
M32230
M331.531.5
M33231
M33330
M351.533.5
M35233
M35332
M36135
M361.534.4
M36234
M36333
M38137
M381.536.5
M38236
M391.537.5
M39237
M39336
M40139
M401.538.5
M40337
M421.540.5
M42240
M42339
M42438
M451.543.5
M45243
M45342
M481.546.5
M48246
M48345
M48444
M501.548.5
M50248
M50347
M521.550.5
M52250
M52349
M52448
M56254
M56452

*All information is strictly informative