COVID-19 UpdatesBrafasco Communications

Tap & Drill Chart

UNC - UNIFIED NATIONAL COARSE

 

Size - Imperial

 

Threads Per Inch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
#1 64 1.50 53 1.55  
#2 56 1.85 50 1.80  
#3 48 2.10 47 2.05 5/64
#4 40 2.35 3/32 2.30 43
#5 40 2.65 38 2.60  
#6 32 2.85 36 2.80 7/64
#8 32 3.50 29 3.40  
#10 24 3.90 25 3.00 5/32
#12 24 4.50 16 4.40 11/64
1/4 20 5.20 13/64 5.10 7
5/16 18 6.60 17/64 6.50 F
3/8 16 8.10 5/16 8.00  
7/16 14 9.50 3/8 9.40 23/64
1/2 13 11.00 27/64 10.80  
9/16 12 12.20 31/64    
5/8 11 13.80 35/64 13.50 17/32
3/4 10   21/32 16.50 41/64
7/8 9 19.50 49/64    
1 8   7/8 22.50  
1-1/8 7   63/64 25.00  
1-1/4 7   1-7/6 28.00  
1-3/8 6 31.00 1-7/32 30.75 1-13/64
1-1/2 6   1-11/32 34.00 1-21/64
1-3/4 5   1-9/16 39.50  
2 4-1/2   1-25/32 45.00  

UNF - UNIFIED NATIONAL FINE

 

Size - Imperial

 

Threads Per Inch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
#0 80 1.25 3/64    
#1 72 1.55 53    
#2 64 1.90 50    
#3 56 2.15 45    
#4 48 2.40 42   3/32
#5 44 2.70 37 2.65  
#6 40 2.95 33 2.90  
#8 36 3.60 9/64 3.50 29
#10 32 4.10 21 4.00 5/32
#12 28 4.70 14 4.60  
1/4 28 5.50 7/32 5.40 3
5/16 24 6.90 17/64 6.80 1
3/8 24 8.50 Q 8.40 21/64
7/16 20 10.00 25/64 9.80  
1/2 20 11.50 29/64    
9/16 18 12.90 33/64 12.80  
5/8 18 14.50 37/64    
3/4 16 17.50 11/16    
7/8 14 20.40 13/16 20.50  
1 12 23.25 59/64 23.50  
1 14* 23.50 15/16    
1-1/8 12 26.50 1-3/64    
1-1/4 12 29.50 1-11/64    
1-3/8 12 33.00 1-19/64    
1-1/2 12 36.00 1-27/64    

*1-12 Thread is UNF
standard, however 1-14
is popular demand and
generally stocked in
place of 1-12.

METRIC COARSE

 

Size - MM

 

Pitch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
1.6 0.35 1.25 3/64    
1.7 0.35 1.35 55    
1.8 0.35 1.45 54    
2 0.40 1.60 1/16    
2.5 0.45 2.05 46    
3 0.50 2.50 40    
3.5 0.60 2.90 33    
4 0.70 3.30 30    
4.5 0.75 3.70 27    
5 0.80 4.30 11/64 4.20 19
6 1.00 5.10 13/64 5.00 9
7 1.00 6.10   6.00 15/64
8 1.25 6.90 H 6.80 17/64
9 1.25 7.90 5/16 7.80  
10 1.50 8.60 11/32 8.50 Q
11 1.50 9.50 3/8    
12 1.75   13/32 10.20 Y
14 2.00 12.20 31/64 12.00 15/32
16 2.00 14.25 9/16 14.00 35/64
18 2.50 15.75   15.50 39/64
20 2.50   45/64 17.50 11/16
22 2.50   23/32 19.50 49/64
24 3.00 21.00 53/64    
27 3.00 24.00 61/64   15/16
30 3.50 26.50 1-3/64    
33 3.50   1-11/64   1-5/32
36 4.00   1-17/64 29.50 1-1/4
39 4.00 35.00 1-3/8 32.00  

METRIC FINE

 

Size - MM

 

Pitch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
4 0.50 3.50 29   9/64
5 0.50 4.50 16    
6 0.75 5.25 5    
7 0.75 6.25 D 6.20 1/4
8 1.00 7.00 J 7.10 9/32
10 1.25 8.75 11/32   S
10 1.00 9.00 T   23/64
12 1.50 10.50 27/64   Z
12 1.25 27/64      
12 1.00 11.00 7/16    
14 1.50 12.50 31/64   1/2
16 1.50 14.75 37/64 14.50 9/16
18 2.00 16.00 5/8    
18 1.50 16.50 21/32 16.50  
20 2.00 18.00 45/64    
20 1.50 18.50 47/64    
22 2.00 20.00 25/32    
22 1.50 20.50 13/16 20.50  
24 2.00 22.00 7/8    
24 1.50 22.50 7/8    

BSW - BRITISH STANDARD WHITWORTH

 

Size - Imperial

 

Threads Per Inch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
1/16* 60 1.20 3/64 1.05  
3/32* 48 1.90 49 1.75  
1/8 40 2.55   2.50 3/32
5/32* 32 3.20 1/8 2.95  
3/16 24 3.70   3.60 9/64
7/32* 24 4.50   4.30 11/64
1/4 20 5.10   5.00 3/16
5/16 18 6.50   6.40 1/4
3/8 16 7.90 5/16 7.80 19/64
7/16 14 9.50   9.20 23/64
1/2 12 10.50     13/32
9/16 12     12.00 15/32
5/8 11 13.50 17/32   33/64
3/4 10 16.50 41/64 16.00 5/8
7/8 9   3/4 19.00 47/64
1 8 22.00 55/64   27/32
1-1/8 7   31/32 24.50 61/64
1-1/4 7 28.00 1-3/32 27.50 1-5/64
1-1/2 6 33.50 1-5/16 33.00 1-19/64
1-3/4 5 39.00 1-17/32 38.50 1-33/64
2 1-1/2 44.50 1-49/64 44.00 1-3/4

BSF - BRITISH STANDARD FINE

 

Size - Imperial

 

Threads Per Inch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
3/16 32 4.00 5/32 3.90  
1/4 26 5.30   5.20 13/64
5/16 22 6.80 17/64 6.70  
3/8 20 8.30 21/64 8.20 5/16
7/16 18     9.50 3/8
1/2 16   7/16 11.00 27/64
9/16 16   1/2 12.50 31/64
5/8 14 14.00 35/64 13.80 17/32
3/4 12     16.50 21/32
7/8 11   25/32 19.50 49/64
1 10   57/64 22.50 7/8
1-1/4 9 28.50 1-1/8   1-7/64
1-1/2 8 34.50 1-23/64   1-11/32
1-3/4 7 40.50 1-19/32 40.00 1-37/64

NPT - NATIONAL PIPE TAPER

 

Size - Imperial

 

Threads Per Inch

TAPPING DRILL SIZE
Preferred Alternative
mm inch mm inch
 1/16 27   D 6.30 1/4
1/8 27   R 8.70 11/32
1/4 18   7/16 11.10  
3/8 18   9/16 14.50 37/64
1/2 14   23/32 18.00  
3/4 14   59/64 23.25 15/16
1 11-1/2   1-5/32 29.00  
1-1/4 11-1/2   1-1/2 38.00  
1-1/2 11-1/2   1-47/64 44.00  
2 11-1/2   2-7/32 56.00  
2-1/2 8   2-5/8 67.00  
3 8   3-1/4 82.50  

 

DRILL SIZE DEC EQUIV. MM   DRILL SIZE DEC EQUIV. MM   DRILL SIZE DEC EQUIV. MM   DRILL SIZE DEC EQUIV. MM
- .0039 0.10   45 .0820 2.08   4 .2090 5.31   15/32 .4688 11.91
- .0079 0.20   44 .0860 2.18   3 .2130 5.41   - .4724 12.00
- .0098 0.25   43 .0890 2.26   7/32 .2188 5.56   31/64 .4844 12.30
- .0118 0.30   42 .0935 2.37   2 .2210 6.61   1/2 .5000 12.70
80 .0135 0.34   3/32 .0938 2.38   1 .2280 5.79   - .5118 13.00
79 .0145 0.37   41 .0960 2.44   A .2340 5.94   33/64 .5156 13.10
1/64 .0156 0.40   40 .0980 2.50   15/64 .2344 5.95   17/32 .5312 13.49
78 .0160 0.41   39 .0995 2.53   - .2362 6.00   35/64 .5469 13.89
77 .0181 0.46   38 .1015 2.58   B .2380 6.05   - .5512 14.00
- .0197 0.50   37 .1040 2.64   C .2420 6.15   9/16 .5625 1429
76 .0200 0.51   36 .1065 2.71   D .2460 6.25   37/64 .5781 14.68
75 .0210 0.53   7/64 .1094 2.78   1/4 .2500 6.35   - .5906 15.00
74 .0225 0.57   35 .1100 2.79   E .2500 6.35   19/32 .5938 15.08
- .0236 0.60   34 .1110 2.79   F .2570 6.53   39/64 .6094 15.48
73 .0240 0.61   33 .1130 2.87   G .2610 6.63   5/8 .6250 15.88
72 .0250 0.64   32 .1160 2.95   17/64 .2656 6.75   - .6299 16.00
71 .0260 0.66   - .1181 3.00   H .2660 6.76   41/64 .6406 16.27
- .0276 0.70   31 .1200 3.05   I .2720 6.91   21/32 .6562 16.67
70 .0280 0.71   1/8 .1250 3.18   - .2756 7.00   - .6693 17.00
69 .0292 0.74   30 .1285 3.26   J .2770 7.04   43/64 .6719 17.07
- .0295 0.75   29 .1360 3.45   K .2810 7.14   11/16 .6875 17.46
68 .0310 0.79   28 .1405 3.57   9/32 .2812 7.14   45/64 .7031 17.88
1/32 .0313 0.79   9/64 .1406 3.57   L .2900 7.37   - .7087 18.00
- .0315 0.80   27 .1440 3.66   M .2950 7.49   23/32 .7188 18.26
67 .0320 0.81   26 .1470 3.73   19/64 .2969 7.54   47/64 .7344 18.65
66 .0330 0.84   25 .1495 3.80   N .3020 7.67   - .7344 18.65
65 .0350 0.89   24 .1520 3.86   5/16 .3125 7.94   3/4 .7500 19.05
- .0354 0.90   23 .1540 3.91   - .3150 8.00   49/64 .7656 19.45
64 .0360 0.91   5/32 .1562 3.97   O .3160 8.03   25/32 .7812 19.84
63 .0370 0.94   22 .1570 3.99   P .3230 8.20   - .7874 20.00
62 .0380 0.97   - .1575 4.00   21/64 .3281 8.33   51/64 .7969 20.24
61 .0394 0.99   21 .1590 4.04   Q .2230 8.43   13/16 .8125 20.64
- .0394 1.00   20 .1610 4.09   R .3390 8.61   - .8268 21.00
60 .0400 1.02   19 .1660 4.22   11/32 .3438 8.73   53/64 .8281 21.03
59 .0410 1.04   18 .1695 4.31   S .3480 8.84   27/32 .8438 21.43
58 .0420 1.07   11/64 .1719 4.37   - .3543 9.00   55/64 .8594 21.84
57 .0430 1.09   17 .1730 4.39   T .3580 9.09   - .8661 22.00
56 .0465 1.18   16 .1770 4.50   23/64 .3594 9.13   7/8 .8750 22.23
3/64 .0469 1.19   15 .1800 4.57   U .3680 9.35   57/64 .8906 22.62
55 .0520 1.32   14 .1820 4.62   3/8 .3750 9.35   - .9055 23.00
54 .0550 1.40   13 .1850 4.70   V .3770 9.56   29/32 .9062 23.02
53 .0595 1.51   3/16 .1875 4.76   W .3860 9.80   59/64 .9219 23.42
1/16 .0625 1.59   12 .1890 4.80   25/64 .3906 9.92   15/16 .9375 23.81
52 .0635 1.61   11 .1910 4.85   - .3937 10.00   - .9449 24.00
51 .0670 1.70   10 .1935 4.91   X .3970 10.08   61/64 .9531 24.21
50 .0700 1.78   9 .1960 4.98   Y .4040 10.26   31/32 .9688 24.61
49 .0730 1.85   - .1968 5.00   13/32 .4062 10.32   - .9842 25.00
48 .0760 1.93   8 .1990 5.05   Z .4130 10.49   63/64 .9844 25.00
5/64 .0781 1.98   7 .2010 5.11   27/64 .4219 10.72   1 1.00 25.40
47 .0785 1.99   13/64 .2031 5.16   - .4331 11.00        
- .0787 2.00   6 .2040 5.18   7/16 .4375 11.11        
46 .0810 1.06   5 .2055 5.22   29/64 .4531 11.51        

 

 

Download the Brafasco Tap & Drill Reference Guide

 

Brafasco accepts no liability for any loss or damage either direct or consequential arising out of or in relation to the use or application of the information or products referred to herein.

Accessibility | Terms of Sale  © Copyright 2022 White Cap Supply Canada Inc. All Rights Reserved.
Use of this site is subject to the White Cap Supply Canada Inc. legal Terms and Privacy.