If you’re looking to tap a 1/8 NPT hole, you’ll need a drill bit that’s just slightly larger than the tap’s minor diameter. In this quick guide, we’ll show you what size drill bit you need for a 1/8 NPT tap.
Checkout this video:
Introduction
You will need a drill bit that is slightly larger in diameter than the tap you are using. The general rule of thumb is to drill a hole that is 1/64” larger than the tap. In this case, you would need a drill bit that is 1/8” in diameter.
The Basics of Drill Bits
There are a few things you need to know before you can answer the question, “What size drill bit do you need for a 1/8 NPT tap?” You need to know what an NPT tap is and what size drill bit you need for the job. Let’s get started.
Types of Drill Bits
There are several types of drill bits, each designed for specific purposes. The most common types are twist bits, spade bits, Forstner bits, and hole saws.
Twist bits are the most versatile and can be used for drilling both wood and metal. They come in a variety of sizes, from very small to quite large. Spade bits are designed specifically for drilling holes in wood, and are not suitable for metal. Forstner bits are designed for drilling clean, precise holes in wood or other soft materials; they’re not suitable for metal either. Hole saws are large-diameter bits that can be used to drill holes in both wood and metal; they’re especially useful for making clean, large-diameter holes in thin materials such as sheet metal.
Sizes of Drill Bits
There are a few different sizes of drill bits, and the right size will depend on the job. The most common sizes are:
-1/16”
-3/32”
-1/8”
-5/32”
-3/16”
-7/32”
-1/4”
-9/32”
These sizes are globally standardized, so you can easily find drill bits in these sizes no matter where you are. In addition to standard drill bits, there are also metric drill bits, which are metric sized. The most common metric sizes are:
2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm
What Size Drill Bit Do You Need for a 1/8 NPT Tap?
Depending on the style of tap you are using, you will need a different size drill bit. A 1/8 NPT tap will require a #7 drill bit. If you are unsure of which size drill bit to use, you can always reference the tap and drill bit chart.
Drill Bit Size for a 1/8 NPT Tap
The right drill bit size for a 1/8 NPT tap depends on the tap’s threading. If the tap has standard threading, you’ll need a #7 drill bit. If it has fine threading, you’ll need a #21 drill bit.
Other Sizes of Drill Bits
3/16 inch – This is the smallest size of drill bit that can be used with a 1/8 NPT tap.
1/4 inch – A 1/4 inch drill bit can be used with a 1/8 NPT tap, but it will create a very tight fit.
5/16 inch – A 5/16 inch drill bit is the largest size that can be used with a 1/8 NPT tap.
Conclusion
After reading this article, you should now have a better understanding of what size drill bit you need for a 1/8 NPT tap. As a general rule of thumb, you should use a drill bit that is two sizes larger than the tap. So, for a 1/8 NPT tap, you would need a 3/16 drill bit. However, it is always best to consult your local hardware store or the manufacturer of your tap to get the best advice.
