Bolt Size | Drill Size | Closest Fractional | Decimal (in) | Decimal (mm) |
9mm-1.25mm | 7.9mm | – | 0.311 | 7.899 |
9mm-1.00mm | 8.1mm | – | 0.319 | 8.1 |
9mm-0.75mm | 8.3mm | – | 0.327 | 8.301 |
9/16-18 NF | 33/64″ | 33/64″ | 0.516 | 13.096 |
9/16-12 NC | 31/64″ | 31/64″ | 0.484 | 12.304 |
8mm-1.25mm | 6.9mm | 17/64″ | 0.272 | 6.899 |
8mm-1.00mm | 7.1mm | – | 0.28 | 7.099 |
8-40 NS | #28 | – | 0.141 | 3.569 |
8-36 NF | #29 | 9/64″ | 0.136 | 3.454 |
8-32 NC | #29 | – | 0.136 | 3.454 |
7mm-1.00mm | 6.1mm | 15/64″ | 0.24 | 6.099 |
7/8-9 NC | 49/64″ | 49/64″ | 0.766 | 19.446 |
7/8-18 NS* | 53/64″ | 53/64″ | 0.828 | 21.034 |
7/8-14 NF | 13/16″ | 13/16″ | 0.813 | 20.638 |
7/16-20 NF | 25/64″ | 25/64″ | 0.391 | 9.921 |
7/16-14 NC | Ltr.U | 23/64″ | 0.368 | 9.347 |
6mm-1.00mm | 5.2mm | – | 0.205 | 5.199 |
6-48 NS | #31 | – | 0.12 | 3.048 |
6-40 NF | #33 | – | 0.113 | 2.87 |
6-36 NS | #34 | – | 0.111 | 2.819 |
6-32 NC | #35 | 7/64″ | 0.11 | 2.794 |
5mm-0.90mm | 4.2mm | – | 0.165 | 4.199 |
5mm-0.80mm | 4.3mm | – | 0.169 | 4.3 |
5/8-18 NF | 37/64″ | 37/64″ | 0.578 | 14.684 |
5/8-11 NC | 17/32″ | 17/32″ | 0.531 | 13.492 |
5/16-32 NEF | 9/32″ | 9/32″ | 0.281 | 7.142 |
5/16-24 NF | Ltr.I | – | 0.272 | 6.909 |
5/16-18 NC | Ltr.F | 17/64″ | 0.257 | 6.528 |
5-44 NF | #37 | – | 0.104 | 2.642 |
5-40 NC | #38 | – | 0.102 | 2.578 |
4mm-0.75mm | 3.4mm | – | 0.134 | 3.399 |
4mm-0.70mm | 3.4mm | – | 0.134 | 3.399 |
4-48 NF | #42 | 3/32″ | 0.094 | 2.375 |
4-40 NC | #43 | 3/32″ | 0.089 | 2.261 |
4-36 NS | #44 | – | 0.086 | 2.184 |
3mm-0.60mm | 2.5mm | – | 0.098 | 2.499 |
3/8-24 NF | Ltr.Q | 21/64″ | 0.332 | 8.433 |
3/8-16 NC | 5/16″ | 5/16″ | 0.313 | 7.938 |
3/4-16 NF | 11/16″ | 11/16″ | 0.688 | 17.463 |
3/4-10 NC | 21/32″ | 21/32″ | 0.656 | 16.667 |
3/16-32 NS | #22 | – | 0.157 | 3.988 |
3/16-24 NS | #26 | – | 0.147 | 3.734 |
3-56 NF | #45 | – | 0.082 | 2.083 |
3-48 NC | #47 | 5/64″ | 0.079 | 1.994 |
24mm-3.00mm | 21.4mm | 53/64″ | 0.843 | 21.4 |
24mm-2.00mm | 22.3mm | – | 0.878 | 22.299 |
22mm-1.50mm | 20.9mm | – | 0.823 | 20.899 |
20mm-2.50mm | 17.8mm | 11/16″ | 0.701 | 17.8 |
2-64 NF | #50 | – | 0.07 | 1.778 |
2-56 NC | #50 | – | 0.07 | 1.778 |
18mm-2.50mm | 15.8mm | 39/64″ | 0.622 | 15.799 |
18mm-1.50mm* | 16.8mm | – | 0.661 | 16.8 |
16mm-2.00mm | 14.2mm | 35/64″ | 0.559 | 14.199 |
16mm-1.50mm | 14.7mm | – | 0.579 | 14.699 |
14mm-2.00mm | 12.2mm | – | 0.48 | 12.2 |
14mm-1.50mm | 12.7mm | – | 0.5 | 12.697 |
14mm-1.25mm* | 12.8mm | – | 0.504 | 12.799 |
14-24 NS | #7 | – | 0.201 | 5.105 |
14-20 NS | #10 | – | 0.194 | 4.915 |
12mm-1.75mm | 10.5mm | – | 0.413 | 10.498 |
12mm-1.50mm | 10.7mm | 27/64″ | 0.421 | 10.698 |
12mm-1.25mm* | 10.9mm | 27/64″ | 0.429 | 10.899 |
12-32 NEF | #13 | – | 0.185 | 4.699 |
12-28 NF | #14 | 3/16″ | 0.182 | 4.623 |
12-24 NC | #16 | 11/64″ | 0.177 | 4.496 |
11mm-1.50mm | 9.7mm | – | 0.382 | 9.698 |
11/16-16 NS | 5/8″ | 5/8″ | 0.625 | 15.875 |
11/16-11 NS | 19/32″ | 19/32″ | 0.594 | 15.083 |
10mm-1.50mm | 8.7mm | – | 0.343 | 8.7 |
10mm-1.25mm | 8.9mm | 11/32″ | 0.35 | 8.898 |
10mm-1.00mm* | 9.1mm | – | 0.358 | 9.101 |
10-32 NF | #21 | 5/32″ | 0.159 | 4.039 |
10-24 NC | #25 | 5/32″ | 0.15 | 3.797 |
1/8-40 NS | #38 | – | 0.102 | 2.578 |
1/4-40 NS | #1 | – | 0.228 | 5.791 |
1/4-32 NEF | 7/32″ | 7/32″ | 0.219 | 5.558 |
1/4-28 NF | #3 | 7/32″ | 0.213 | 5.41 |
1/4-24 NS | #4 | – | 0.209 | 5.309 |
1/4-20 NC | #7 | 13/64″ | 0.201 | 5.105 |
1/2-24 NS | 29/64″ | 29/64″ | 0.453 | 11.509 |
1/2-20 NF | 29/64″ | 29/64″ | 0.453 | 11.509 |
1/2-13 NC | 27/64″ | 27/64″ | 0.422 | 10.716 |
1.8 NC | 7/8″ | 7/8″ | 0.875 | 22.225 |
1.12 NF | 59/64″ | 59/64″ | 0.922 | 23.416 |
1-72 NF | #53 | 1/16″ | 0.06 | 1.511 |
1-64 NC | #53 | – | 0.06 | 1.511 |
1-14 NS | 15/16″ | 15/16″ | 0.938 | 23.813 |
1 3/8-6 NC | 1 7/32″ | 1 7/32″ | 1.219 | 30.958 |
1 3/8-12 NF | 1 19/64″ | 1 19/64″ | 1.297 | 32.941 |
1 1/8-7 NC | 63/64″ | 63/64″ | 0.984 | 25.004 |
1 1/8-12 NF | 1 3/64″ | 1 3/64″ | 1.047 | 26.591 |
1 1/4-7 NC | 1 7/64″ | 1 7/64″ | 1.109 | 28.179 |
1 1/4-12 NF | 1 11/64″ | 1 11/64″ | 1.172 | 29.766 |
1 1/2″-12 NF | 1 27/64″ | 1 27/64″ | 1.422 | 36.116 |
1 1/2-6 NC | 1 11/32″ | 1 11/32″ | 1.344 | 34.133 |
0-80 NF | 3/64″ | 3/64″ | 0.047 | 1.191 |
People Also Ask About the Tap Drill Size Chart
What size drill do I need for a tap?
To determine the size of the drill bit you need for tapping, you typically refer to a tap and drill chart or consult the manufacturer’s recommendations. The drill size depends on the specific thread size and type of tap you are using.
What size drill bit for a 7/8 tap?
To tap a hole for a 7/8-inch thread, you would typically use a drill bit that is slightly smaller in diameter than 7/8 inch. The exact size would depend on the type of tap (e.g., standard or metric) and the thread pitch.
What is the size of drill tap 8-32?
An 8-32 tap typically requires a drill bit sized #29 for a through-hole or #36 for a blind hole in standard fractional sizes. The specific size may vary depending on your application and the type of tap.
How big is a 10-32 hole?
A 10-32 threaded hole is designed for a screw or bolt with a 10-32 UNF (Unified National Fine) thread. The hole size for this thread is typically around 0.1900 inches in diameter.
What is a tap drill chart?
A tap drill chart is a reference tool that provides information on the recommended drill bit sizes for various tap sizes and thread types. It helps you determine the correct drill size to use when preparing a hole for tapping.
What size hole do I drill for a 1/2 tap?
To tap a hole for a 1/2-inch thread, you would typically use a drill bit that is slightly smaller in diameter than 1/2 inch. The exact size would depend on the type of tap and thread pitch you are using.
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