Tap and Drill Chart
For 75% thread depth use this chart.
|
Tap size
|
Correct drill size
|
Closest fractional bit size
|
Decimal equivalant
|
|
0-80 NF
|
3/64"
|
3/64"
|
.0469
|
|
1-72
|
#53
|
1/16"
|
.0595
|
|
3-48
|
#47
|
5/64"
|
.0785
|
|
4-40
|
#43
|
3/32"
|
.0890
|
|
4-48
|
#42
|
3/32"
|
.0935
|
|
6-32
|
#35
|
7/64"
|
.1100
|
|
8-36
|
#29
|
9/64"
|
.1360
|
|
8-32
|
#29
|
9/64"
|
.1360
|
|
10-24
|
#25
|
5/32"
|
.1495
|
|
10-32
|
#21
|
5/32"
|
.1590
|
|
12-24
|
#16
|
11/64"
|
.1770
|
|
12-28
|
#14
|
3/16"
|
.1820
|
|
1/4"-20
|
#7
|
13/64"
|
.2010
|
|
1/4"-28
|
#3
|
7/32"
|
.2130
|
|
1/4"-32
|
7/32"
|
<---
|
.2188
|
|
5/16"-18
|
letter F
|
17/64"
|
.2570
|
|
5/16"-24
|
17/64"
|
<---
|
.2656
|
|
3/8"-16
|
5/16"
|
<---
|
.3125
|
|
3/8"-24
|
letter Q
|
21/64"
|
.3320
|
|
7/16"-14
|
letter U
|
23/64"
|
.3680
|
|
7/16"-20
|
25/64"
|
<---
|
.3906
|
|
1/2"-13
|
27/64"
|
<---
|
.4219
|
|
1/2"-20
|
29/64"
|
<---
|
.4531
|
|
1/2"-24
|
29/64"
|
<---
|
.4531
|
|
9/16"-12
|
31/64"
|
<---
|
.4844
|
|
9/16"-18
|
33/64
|
<---
|
.5156
|
|
5/8"-11
|
17/32"
|
<---
|
.5312
|
|
5/8"-18
|
37/64"
|
<---
|
.5781
|
|
11/16"-11
|
19/32"
|
<---
|
.5938
|
|
11/16"-16
|
5/8"
|
<---
|
.6250
|
|
3/4"-10
|
21/32"
|
<---
|
.6562
|
|
3/4"-16
|
11/16"
|
<---
|
.6875
|
Cutting Fluid
Use of the proper cutting lubricant will make better threads and prolong tap and die service life. For small holes in thin materials you can get away without any lube.
|
Material to be tapped
|
Lube to use
|
|
aluminum
|
kerosene
|
|
brass
|
kerosene
|
|
bronze
|
kerosene
|
|
steel
|
cutting oil
|
|
stainless steel
|
kerosene mixed with cutting oil
|
|
hardwood
|
dry
|
Clearance Drill Sizes
|
Screw or bolt nominal size
|
Clearance drill size
|
|
#0
|
51
|
|
#1
|
47
|
|
#3
|
36
|
|
#4
|
31
|
|
#6
|
25
|
|
#8
|
16
|
|
#10
|
13/64"
|
|
#12
|
7/32"
|
|
1/4"
|
17/64"
|
|
5/16"
|
21/64"
|
|
3/8"
|
25/64"
|
|
7/16"
|
29/64"
|
| 
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