What size drill bit do I need to tap 1/4-20 hole?

The best overall size drill bit for 1/4″ 20 tap is a #7 drill bit, the measurement being 13/64”.

What is the tap drill size for 1/4 NPT?

7/16″
NPT Tap Drill Chart

Tap Size	Drill Size	Tap and Drill Set
1/4″ NPT Tap	7/16″ Drill Bit	1/4″ NPT Tap and Drill Set
3/8″ NPT Tap	37/64″ Drill Bit	3/8″ NPT Tap and Drill Set
1/2″ NPT Tap	23/32″ Drill Bit	1/2″ NPT Tap and Drill Set
3/4″ NPT Tap	59/64″ Drill Bit	3/4″ NPT Tap and Drill Set

What is the drill size before tapping for ¼ 20 Unc?

Thread-Forming Taps For example, the recommended drill size for a 1/4-20 UNC thread is a No. 1 (0.228″-dia.)

What size is #20 drill bit?

Drill Bit Size Chart

Size	Decimal Equivalent	Size
74	0.0225	21
.60 mm	0.0236	20
73	0.024	4.10 mm
72	0.025	4.20 mm

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 is a 1/4 NPT thread?

NPT fittings are listed by the “standard” inner diameter (I.D.) of the fitting. The outer diameter (O.D.) of the threads is usually about 1/4 (0.250) in.

What does NPT stand for?

National Pipe Thread Tapered
NPT is the abbreviation for National Pipe Thread Tapered, which is the U.S. standard for tapered threads used to join pipes and fittings. They were established as a standard by the American National Standard Pipe Thread, commonly referred to as the national pipe thread standards.

How do I know what size my tap is?

As a rule of thumb, for Metric threads, the tapping drill can be calculated by subtracting the pitch from the diameter of the thread. eg for an M5x0. 75 thread the tapping drill is 5-0.75mm = 4.25mm. For Imperial (inch) threads the tapping drill size is calculated in the same way, diameter minus pitch.

What size drill bit is 1 4?