National Pipe Thread Taper, commonly known just as NPT, is a U.S. standard for tapered threads used on threaded pipes and fittings. This standard is widely used all over North America. Pipe thread sizes are usually based on the inside diameter (ID) or flow size. The way to read an NPT size is the nominal inside diameter and the number of threads per inch. For example, if we have a 1/4-18 NPT, that means it is a 1/4 inch inside diameter and 18 threads per inch. If LH is added to the end, it means the pipe has a left-handed thread. First up, we have the trusty old steel taps. These bad boys are a reliable option for those on a budget but remember that they might not be the best choice for heavy-duty or precision work. Choosing the right tap material is crucial for a successful tapping job, especially when working with a 1/8 NPT tap. So, let’s talk about the best materials to ensure you get it right the first time! Taper of Thread: The taper on all NPT Thread is 1 in 16, or 0.75” per 1 foot, with the center line bisecting the angle created. The corresponding half-angle of the taper relative to the center line is 1 degree, 47 minutes or 1.79°.

1/8-27 NPT : Pipe Thread Dimensions (Machining Doctor) 1/8-27 NPT : Pipe Thread Dimensions (Machining Doctor)

Drilling and tapping might initially seem intimidating, but it can be a breeze with the right tools. Now, for the drill bit size, the secret lies in subtracting the pitch of the thread from its diameter. For a 1/8″ NPT tap, the magic letter is anR-shaped drill bit. Create a Sketch on the Right Plane which intersects the helix created. On this sketch we will define the thread profile. Now, before drilling, mark the spot where you want your hole. That way, you know exactly where your drill is going, and you minimize any errors. Plus, it keeps everything looking neat! NPT is defined by ANSI/AMSE standard B1.20.1, and in this article we’ll be specifically referencing the ANSI/ASME B1.20.1-1983, including its charts and tables.The 1/8″ NPT tap’s diameter is not 0.125 inches, but based on the thread on the end of a 1/8-inch pipe, it’s approximately0.405 inchesin the “big” diameter.

1/8 BSP and 1/8 NPT Taps and Dies – Best Fittings

Create a Sketch on the new face of this extrusion and draw a Circle equal to the inner diameter of the pipe. In NPT threads chamfers are not required, although a chamfer may be present, there are no specifications on the angle and depth of the chamfer. These coatings can get a little pricey, but trust me; they’re worth it if you want to up your game. This creates a lead-in chamfer at the end of the thread. This is a result of the chamfer on the die during fabrication, which creates imperfect threads at the and of the thread. I recommend high-speed steel taps if you’re looking for something with a bit more oomph. These are specifically designed for fast cutting and feature excellent wear resistance.In this example, we are modeling a standard pipe, 1-1/2 NPT Pipe Size, at 11-1/2 Threads per Inch. We will use specific points on this reference sketch to define our pipe. Width of Flat, F: Width of the flat caused by truncation, or shortening of the thread crest or root. Create a S ketch on the rear face of the extrusion. Once again, draw a circle equal to the outer diameter of the pipe. The angle between the sides of the thread is 60° when measured with a line bisecting the angle, perpendicular to the center axis.

1/8 Pipe Size Taps | McMaster-Carr

These values may also be acquired using the formulas contained in the ANSI/ASME B1.20.1. Note that the listed dimensions are in inches and are given to four or five decimal places only to avoid errors in computation, these do not indicate required precision. For other types of tapered threads such as Aeronautical National External Threads, ANPT, the end must be chamfered 45° with a specified depth define in the ASE AS71051 Standard. National Pipe Thread Taper or NPT threaded pipes and fittings are deployed in a variety of fields where transportation or containment of liquids, gases, steam, or hydraulic fluid is required. The NPT geometry allows internal and external thread surfaces to further engage when torque is applied to the thread assembly. This creates a fluid-tight seal. With NPT, as opposed to NPTF, the use of a sealing compound or tape is typically applied to the threads to complete the seal. Because of NPT’s mating and sealing capabilities, a practical knowledge of the NPT thread is a valuable addition to an engineer’s toolbox. First, you’ll want to ensure you got the right size drill bit. In our case, we need anR-shaped drill bit equivalent to 0.339 inches or 8.61 mm.External Thread Overall Length, L4: Total length of the external threads, included incomplete threads, or longer just as long as the total thread length is covered. To account for tolerance and precision during the fabrication of these threads, refer to guides such as this one, which explains how to use external and internal NPT thread gauges. These go-no-go gauges control quality of NPT threads during fabrication.