# How do you calculate NPT drill size?

## How do you calculate NPT drill size?

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 do you use for a 1/8 NPT tap?

Size Of The Drill Bit A 1/8″ NPT tap requires an R-shaped drill bit. The R drill bit corresponds to a size of 0.339 inches or 8.61 mm.

What is the tap drill size for 1/16 NPT?

27 15/64

Tap size Threads per inch Drill size w/ taper pipe reamer
1/16 27 15/64
1/8 27 21/64
1/4 18 27/64
3/8 18 9/16

### What is the drill size for 1/2 NPT tap?

23/32″
NPT Tap Drill Chart

Tap Size Drill Size 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
1″ NPT Tap 1-5/32″ Drill Bit 1″ NPT Tap and Drill Set

### What is NPT hole?

National Pipe Thread Taper ( NPT ) is a U.S. standard for tapered threads used on threaded pipes and fittings . In contrast to straight threads that are found on a bolt, a taper thread will pull tight and therefore make a fluid-tight seal.

What is the diameter of 1/8 NPT?

0.405
Basic Dimensions, American National Standard Taper Pipe Threads, NPT, (ANSI B2. 1-1968)

Nominal Pipe Size Outside Diameter of Pipe Threads per Inch
1/16 0.313 27
1/8 0.405 27
1/4 0.540 18
3/8 0.675 18

## What size hole do I drill for a 1/4 NPT tap?

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

## Are NPT taps tapered?

NPT tap threads can be either tapered or straight, depending on the job at hand. The taper on NPT pipe taps means a seal is tightly formed when correctly torqued.

What does NPT tap mean?

NPT stands for National Pipe Tapered threads, also known as ANSI/ASME B1. 20.1 pipe threads. It is a U.S. standard for measuring tapered threads on threaded pipes and fittings. Threaded pipes can give an effective seal for pipes using hydraulic fluids.

### What is the diameter of 1/2 inch NPT?

Basic Dimensions, American National Standard Taper Pipe Threads, NPT, (ANSI B2. 1-1968)

Nominal Pipe Size Outside Diameter of Pipe Wrench Makeup Length for Internal Thread
1/8 0.405 0.1111
1/4 0.540 0.1667
3/8 0.675 0.1667
1/2 0.840 0.2143

### What does 1 4 inch NPT mean?

How are they measured? NPT fittings are listed by the “standard” inner diameter (I.D.) of the fitting. (We put “standard” in quotes because the I.D. of the fitting will vary, depending on the manufacturer.) The outer diameter (O.D.) of the threads is usually about 1/4 (0.250) in.