|
Thread Sizes and Tap Drills (USA)
| Thread Size* |
Basic Major Diameter |
Tap Drill Size** |
| #0-80 |
.0600 |
3/64 |
| #2-56 |
.0860 |
#50 |
| #2-64 |
.0860 |
#50 |
| #4-40 |
.1120 |
#43 |
| #4-48 |
.1120 |
#42 |
| #5-40 |
.1250 |
#38 |
| #5-44 |
.1250 |
#37 |
| #6-32 |
.1380 |
#36 |
| #6-40 |
.1380 |
#33 |
| #8-32 |
.1640 |
#29 |
| #8-36 |
.1640 |
#29 |
| #10-24 |
.1900 |
#25 |
| #10-32 |
.1900 |
#21 |
| 1/4-20 |
.2500 |
#7 |
| 1/4-28 |
.2500 |
#3 |
| 5/16-18 |
.3125 |
F |
| 5/16-24 |
.3125 |
I |
| 3/8-16 |
.3750 |
5/16 |
| 3/8-24 |
.3750 |
Q |
| 7/16-14 |
.4375 |
U |
| 7/16-20 |
.4375 |
25/64 |
| 1/2-13 |
.5000 |
27/64 |
| 1/2-20 |
.5000 |
29/64 |
| 9/16-12 |
.5625 |
31/64 |
| 9/16-18 |
.5625 |
33/64 |
| 5/8-11 |
.6250 |
17/32 |
| 5/8-18 |
.6250 |
37/64 |
| 3/4-10 |
.7500 |
21/32 |
| 3/4-16 |
.7500 |
11/16 |
| 7/8-9 |
.8750 |
49/64 |
| 7/8-14 |
.8750 |
13/16 |
| 1-8 |
1.0000 |
7/8 |
| 1-14 |
1.0000 |
15/16 |
| 1 1/8-7 |
1.1250 |
63/64 |
| 1 1/8-12 |
1.1250 |
1 3/64 |
| * Coarse series shown in bold. |
| ** Closest size for 75% theoretical thread. |
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