When working with pipes and fittings, it is important to know the proper tap drill size for the job. A ¼ NPT tap drill size is a standard size used when tapping a hole in metal to accept a ¼ inch of National Pipe Thread (NPT).
This size is used with a variety of pipe and fitting sizes, including 1/8, 1/4, 3/8, 1/2, and 3/4-inch NPT threads. If you want to know more about it, where it’s used, and more, here’s a quick guide:
How to Use a ¼ NPT Tap
It is important to use the proper tap and drill bit sizes to ensure a secure connection. The tap drill size should be chosen based on the size of the NPT thread and the material being tapped.
For a ¼ NPT thread, the recommended tap drill size is 7/16 inches. Before beginning the tapping process, it is important to ensure that the drill bit is sharp and the tap is lubricated.
When tapping a hole for a ¼ inch of NPT thread, it is important to follow the correct tapping procedure. The hole should be drilled with a 7/16-inch drill bit and the tap should be inserted into the hole. 
The tap should be turned clockwise and turned until it is flush with the surface. The tap should be turned a few more times to ensure a secure connection.
What Drill Size to Use for a 1/4 NPT Tap?
The correct size drill bit for a 1/4 NPT tap is 7/16 inches. This size is recommended for a variety of pipe and fitting sizes, including 1/8, 1/4, 3/8, 1/2, and 3/4-inch NPT threads. It is important to ensure that the drill bit is sharp and the tap is lubricated before beginning the tapping process.
Thread Size for 1/4 NPT?
A 1/4 NPT thread is a National Pipe Thread with a nominal diameter of 1/4 inch. This size is commonly used for a variety of applications, including home plumbing, automotive, and industrial applications.
Conclusion
When working with pipes and fittings, knowing the correct tap drill size is essential. The ¼ NPT tap drill size is 7/16 inch and is used with a variety of pipe and fitting sizes, including 1/8, 1/4, 3/8, 1/2, and 3/4 inch NPT threads.
It is important to use the right tap and drill bit size to ensure a secure connection. Following the correct tapping procedure is also essential to ensure a secure connection.