What is a 1/2 Tap Drill Size
A 1/2 tap drill size is the size of drill bit required to create the threads on a 1/2 inch pipe or threaded hole. The size of the drill bit depends on the type of material being tapped. Generally, a 29/64-inch drill bit is used when tapping into steel, while a 7/16-inch drill bit is recommended for softer materials like aluminum and copper.
What Size Drill Do I Need for a 1/2 Tap?
The size of the drill bit you need for a 1/2 tap depends on the type of material [1] you are working with. Generally, when tapping into steel, you will need to use a 29/64-inch drill bit. If you are tapping into softer materials such as aluminum or copper, then a 7/16-inch drill bit is recommended.
What is the Formula for Tap Drill Size?
The formula for tap drill size is Drill Size = (Major Thread Diameter – Pitch) / 2. For a 1/2 tap, the major thread diameter is 0.5 inches and the pitch is 20 threads per inch. Therefore, the drill size for this tap would be (0.5 – 0.02) / 2 = 0.24 inches, or 29/64 inches.
Tap Drill Sizes
The following table outlines the tap drill sizes for common sizes of taps:
| Tap Size | Drill Size |
| 1/4 | 7/32 |
| 5/16 | 21/64 |
| 3/8 | 27/64 |
| 7/16 | 29/64 |
| 1/2 | 29/64 |
| 9/16 | 33/64 |
| 5/8 | 21/32 |
| 3/4 | 27/32 |
| 7/8 | 1 1/16 |
| 1 | 1 3/32 |
Where Can I Use 1/2 Tap Drill Size?
A 1/2 tap drill size can be used for a variety of applications. It is commonly used for creating threaded holes in steel, aluminum, and other soft metals. It can also be used for creating threads in plastic and other softer materials. This size tap is also often used for creating threads in wood and other softer materials.
Summary
The size of the drill bit you need for a 1/2 tap depends on the type of material you are working with. Generally, when tapping into steel, you will need to use a 29/64-inch drill bit. The formula for tap drill size is Drill Size = (Major Thread Diameter – Pitch) / 2. A 1/2 tap drill size can be used for a variety of applications, such as creating threaded holes in steel, aluminum, and other soft metals, and in plastic and other softer materials. It can also be used for creating threads in wood and other softer materials.