What size hole do I drill for a 1/4 inch tap?
The best overall size drill bit for 1/4″ 20 UNC tap thread is a #7 drill bit, the measurement being 13/64” (0.203″diameter).
What size drill bit do I need for a 1/4 20 tap?
13/64″
US Tap and Drill Bit Size Table
| Tap | Fractional Drill Bit | Letter Drill Bit |
|---|---|---|
| #12-24 | 11/64″ | – |
| 1/4″-20 | 13/64″ | – |
| 1/4″-28 | 7/32″ | – |
| 5/16″-18 | 17/64″ | F |
What size hole do you drill for a 1/4-28 tap?
Tap Drill Size Chart
| Bolt Size | Drill Size | Closest Fractional |
|---|---|---|
| 1/4-28 NF | #3 | 7/32″ |
| 1/4-32 NEF | 7/32″ | 7/32″ |
| 1/4-40 NS | #1 | – |
| 7mm-1.00mm | 6.1mm | 15/64″ |
What is the tapping drill size for 1 ⁄ 4 BSW thread?
British Standard Whitworth (BSW) is an imperial-unit-based screw thread used for ISO 7-1 and ISO 228 threads (formerly BS-2779)….Taps and drill sizes used for Whitworth – ISO 7 and ISO 228 threads.
| Size Taps (inches) | TPI | 75% Drill Size for Pipe Taps (inches (mm)) |
|---|---|---|
| 1/4 | 20 | #9 (5.1) |
| 3/8 | 16 | 5/16 (8) |
What does a 1/4-20 tap mean?
1/4-20. The thread size is 1/4-20 – this means that the nominal diameter is 1/4î and that there are 20 threads per inch. The pitch is the distance between each thread. When there are 20 threads per inch, the distance between each thread is the reciprocal of the TPI (1/20 = 0.05î).
What size is a #25 drill bit?
| To Tap This Size Screw Or Bolt: | Use This Drill Bit: | Decimal Inches |
|---|---|---|
| 10-24 NC | #25 | .1495 |
| 3/16-32 NS | #22 | .1570 |
| 10-32 NF | #21 | .1590 |
| 5mm-0.90mm | 4.2mm | .1653 |
What is BSW and BSP threads?
British Standard Whitworth (BSW) is an imperial-unit-based screw thread standard, devised and specified by Joseph Whitworth in 1841 and later adopted as a British Standard. It was the world’s first national screw thread standard, and is the basis for many other standards, such as BSF, BSP, BSCon, and BSCopper.