3/8-16 Tap Drill Size – Complete Guide

When tapping a hole, it is essential to use a drill size that is the same as, or slightly smaller than, the tap size. If the drill size is too large, the tap may break, and if the drill size is too small, the tap may not be able to cut the hole.

The most common tap drill size is 3/8-16, which is used to tap holes with a diameter of 3/8 inches. This size tap can be used to tap holes in a wide variety of materials, including steel, aluminum, brass, and plastic.

What Is Drill Size for 3/8-16 Tap?





The tap drill is the size of the hole that you will need to create in order to accommodate the specific fastener. In the case of a 3/8-16 tap drill, the “-16” denotes the number of threads per inch, while the “3/8″ is the diameter of the screw or bolt.

3/8-16 tap drill size is 5/16”. This is because the tap will create a thread that is slightly smaller than 3/8″ in diameter, and the drill should be slightly smaller than that so the threads can properly engage.

Using a drill bit that is too small will make it difficult to start the tap, and can also cause the tap to break. Using a drill bit that is too large will make it difficult to keep the tap straight, and can also cause the tap to break. In either case, breaking a tap can cause serious injury, so it is always best to use the recommended drill size.

Orange&black drill in the hand

How to Choose 3/8-16 Drill Size?

When it comes to drilling bits, there are a few factors to consider. The size of the bit, the type of material it is being used to drill, and the strength of the drill. The size of the drill bit is determined by the size of the screw or bolt that it is being used to drill. The most common drill bit sizes are 1/16, 1/8, 3/16, 1/4, 5/16, 3/8, and 1/2 inch. The size of the drill bit that is needed for a 3/8-16 tap is a 3/8 inch bit.

The type of material that the drill bit is being used to drill is also important. There are different drill bits for drilling metal, wood, and plastic. The drill bit that is used to drill metal needs to be a bit harder than the drill bit that is used to drill wood or plastic. The strength of the drill is also important. Some drills are more powerful than others and can drill through tougher materials.

When drilling a hole for a screw or bolt, it is important to use a drill bit that is the same size as the screw or bolt. If the drill bit is too small, the screw or bolt will not fit in the hole. If the drill bit is too big, the screw or bolt will be loose in the hole. The drill bit that is needed for a 3/8-16 tap is a 3/8-inch bit.

How to Drill With a 3/8-16 Tap?

To drill with a 3/8-16 tap, you first need to find the center of the hole you want to tap. To do this, you can use a ruler or a measuring tape. Once you have found the center, you need to drill a pilot hole. This hole should be smaller than the tap. A good rule of thumb is to drill a hole that is about 80% the size of the tap.

Once you have drilled the pilot hole, you can start tapping the hole. To do this, you will need to insert the tap into the hole and start turning it clockwise. As you turn the tap, it will cut threads into the hole. You will need to turn the tap until it is flush with the surface of the material.

Once the tap is flush with the surface, you can remove it from the hole. You may need to use a tap wrench to hold the tap while you turn it. Finally, you can insert a screw into the hole and tighten it.

Drilling hole for the table in the wall


How to Calculate a 3/8 Drill Bit in mm?

To calculate the size of a 3/8 drill bit in mm, you must first determine the size of the hole that you need to drill. To do this, use a drill bit gauge to measure the circumference of the hole and then use that number to calculate the size of the drill bit you need. For example, if the hole is 15 mm in circumference, you would need a drill bit 3/8ths of an inch in size.

How to Choose a Drill Bit for a 3/8 Bolt?

There is no definitive answer to this question because it depends on a variety of factors, such as the material of the bolt, the size of the hole, and the type of drill bit. However, in general, a 3/8 drill bit should be able to create a hole that is slightly larger than the diameter of the bolt.


All in all, the 3/8-16 tap drill size is the most important to know if you are looking for a tap. This is because it is the most commonly used size in the United States, it is the most common size for machine shops, and it is also the most common size for home improvement projects.

Ronnie Collins

Ronnie Collins

I’m Ronnie Collins. I’ve been passionate about gardening and woodworking all my life and even earned an MS degree in Botany from the University of Maryland. I’ve been working at a gardening company for a while, so I know the ropes about a whole lot of dedicated equipment such as the table saw, track saw, lawnmowers, chainsaws, garden hoses, and much more.

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