1/4″ 20 Tap Drill Size

1/4" 20 Tap Drill Size

Drill bits are useful tools that almost everyone will find they need at some point. It doesn’t matter if you’re a DIYer or a professional. However, if you want to avoid damaging whatever material you’re drilling into, you have to know essential information on drill bits. For example, what is a 1/4″ 20 tap drill size?

When drilling, you have to be familiar with the wide variety of sizes and kinds of drill bits, as well as what makes them different. I would also like to mention that it’s crucial that you keep in mind that drill bits are not all the same size. They are made in a variety of sizes to serve a certain purpose.

This article covers how a drill bit works, what are the different drill bit sizes, what size drill bit you need for a ¼” 20 tap drill, and more! Keep reading to find the best drill bit for whatever project you’re working on.

How Does a Drill Bit Work?

Drill bits are truly a crucial component of professional and DIY enthusiast toolsets.

For example, it would be very challenging to carry out basic building operations without them. There is nothing too large or too little for drill bits; you can drill and fasten roof frames and hang pictures. 

The drill’s chuck holds a drill bit in position. When you turn the drill on, the chuck spins, producing the axial speed and torque required to make a hole. The chuck firmly grips the drill bit, which effectively holds it in place until the user removes it. Drill bits have a shank on one end that fits into the chuck and cutting edges on the other.

The components and features of drill bits can vary, but the most common features are as follows:

  1. The Spiral: The spiral is the rate of the twist the drill bit does. This determines the pace of chip removal.
  2. Point Angle: The point angle is the angle produced at the cutting point of the bit. If you are drilling into a variety of materials, you will need drill bits with various tip angles.
  3. The Lip Angle: This determines how much help the drill bits cutting edge will receive.
  4. The Mechanic: This is what suppliers use frequently to determine drill bit length.

What Are the Drill Bit Sizes?

There would be an unlimited number of drill bits if bits were based on holes. However, several kinds of standard-sized bits and holes are available to purchase.

There are only a few hundred appropriate drill bit sizes for each application. There are sizes for construction projects, maritime, hobbies, farming, aviation, metalworking, woodworking, arts and crafts, equipment, commercial building projects, and more.

Twist Bits

Twist bits have front edges that cut through the material and remove the remains from the gap, all the while keeping the bit straight. 

Spur Point Bit

Spur point bits have raised spurs and a focal point. Both of these features assist in keeping the bit straight, so you can drill in a straight line. 


Countersink bits are made to be used on delicate materials like plastic and timber. 

Flat Wood Bit

These bits were designed for power drills only. The flat steel on the sides removes timber while the middle makes a hole.

Forstner Bit

These bits are used to frame holes with a base that’s level. This means if you need to install kitchen cabinet hinges, this is the bit you want to go with. 


Auger bits are used to remove dust and chips. It really helps make a clean hole. 


Self-feed drill bits help in the positioning of the bit. It’s one of the more compact drill bits. 

Masonry Bit

These drill bits were made to drill into quarry tiles, brick, concrete, stone, and block. 

Bullet Pilot Point

Bullet pilot point drill bits have two spurs and a focal point. They’re similar to spur point bits. However, they can be used on wood, plastic, and metal.

Tile Bit

This type of bit is used for drilling glass and ceramic tiles. They almost always have a ground tungsten carbide tip. 

Hole Saw

Hole saw bits allow you to make big-diameter holes in plastic and wood. 

Wood Auger 

Wood augers are great for drilling deep, large holes into man-made boards and wood. 

Plug Cutter

Plug cutters bore holes into wood. It’s crucial that if you need a plug cutter to get one of high quality. This way, you will get accurate wood plugs for screws. 

Step Drill Bit 

Step drill bits can drill holes into metal and wood up to 0.25 inches deep. It can also drill holes of various diameter sizes. 

Most high-quality bit sets have drill bit sizes that range from 12 to 30. You can see how many drill bit sizes there are below.

Let’s start with a simple multi-purpose set. The drill bit sizes shown below are standard fractional sizes for that kind of set.


I would like to mention that there are larger sets available. There are specialty fasteners that may need a bit of size that’s considered uncommon.

Drill bit sizes lower than 1/16 inches and bigger than 1-1/2′ inches would be included in drill bit sets that have a wider variety of drill bit sizes.

The typical drill bit sizes for 13-pieces are as follows: 1/4′′, 3/8′′, 1/2′′, 5/8′′, 11/16′′, 3/4′′, 7/8′′, 9/16′′, 1′′, 1-1/8′′, 1-1/4′′, 1-3/8′′, and 1-1/2′′.

What Size Drill Bit For a 1/4″20 Tap?


You may find that you need to tap new threads into metal from time to time. If you’re someone who uses tools and drill bits for home projects, then this probably doesn’t happen to you very often. Before tapping, you will want to drill a hole smaller than the tap but large enough to cut the edges.

Tapping threads seems like a simple idea, but it can get complicated when you try to execute it.

If the hole is too small, the tap will go too far into the center, meaning it would be difficult to screw the bolt into the hole. However, if the hole is too big, the bolt will not match the threads.

One of the most popular sizes is a ¼” with 20 threads per inch. You would this what size drill bit to use for 1/4′′ 20 taps would be commonly known, but it’s not. The drill bit size you need for a 1/4′′ 20 tap is a #7 drill bit with a 13/64″ dimension.

How To Use a Drill Bit for a 1/4″ 20 Tap Drill

Follow the steps below to properly use a drill bit for a ¼” 20 tap drill

Step 1:

Determine where the position of the 1/4″ 20 tapped hole is. Then, use a tape measure and locate the hole. Next, mark its position with the scribe.

Step 2:

Align the drill bits’ center punch’s tip with where the hole is to be tapped. Next, you’ll want to create a depression for the hole placement. To do this, hit the rear of the center punch with a hammer. Doing this will prevent the bit from straying from the hole’s center.

Step 3:

Now, place the drill bit in the drill. To ensure the drill bit is secure, tighten the chuck of the drill. Put a tiny amount of cutting fluid into the drill bit. Next, place the bit’s tip on the mark that you made in the center.

Step 4:

Press down on the drill trigger. Drill the hole, stop, and add more cutting fluid to the bit. This will cool the drill, drill bit, and metal.

Step 5:

Place the ¼” 20 tap in the tee handle. Next, make sure that you secure the tap completely inside the tee handle. If the tap becomes loose, it can break while you’re threading the metal.

Now, cut the tap with cutting fluid and start the tap in the hole while keeping the tee handle level. Thread the tap into the hole by turning the tee handle clockwise.

If you find that the tap has become stuck, spin the tee handle ¼  turn counter-clockwise. Then, turn the tap into the hole over and over again. Thread the tap through the hole until it reaches the bottom. To remove the tap, turn it counterclockwise.

Step 6:

Now, you want to mount the flapper wheel on the grinder. Next, remove the burr from both sides of the tapped hole using the grinder.

To verify that the hole is threaded properly, insert a ¼” 20 bolt into it. If the bolt won’t thread, clean the tap and apply cutting fluid to both the tap and threaded hole. Tap the hole once again to clean the threads.

Frequently Asked Questions

Here are some frequently asked questions and answers to help you learn more about ¼” 20 tap drill size.

What should also be considered for Drilling 1/4″ 20 Tap?

When drilling any kind of material for tapping, whether it be wood, metal, plastic, concrete, etc. Decide before you start tapping whether you will tap with 50% or 75%. This will vary depending on the hardness of the material.

How to read a drill bit size?

Drill bits are available in metric, fractional, letter dimensions, and wire gauge numbers. Fractional measurements are in inches, and metric measurements are in millimeters. 

The wire gauge number and letter dimensions systems correspond to tool sizes that increase as the wire gauge decreases from #107 to #1. The same concept applies to the letter dimensions; they increase as the dimensions decrease from A to Z. 

How to know which size of a drill bit to use?

Place the shaft of the drill bit in front of the screw. When you do this, you should only be able to see the threads of the screw. The drill bit is too large if you can’t see the threads of the screw. The bit is too small if you can see more than the threads of the screw.

Wrapping Up

There was ¼” 20 Tap Drill Size! Now that you know everything you need to know about drill bits and the size needed for a ¼” 20 tap drill, hopefully, you can get what you need. No matter which option you choose, you’ll be able to work on the projects you want with ease.

The appropriate drill bit size for a 1/4′′ 20 tap drill is determined by the thread’s coarseness. Remember to check the hardness of the material that you’ll be drilling through.

However, I would like to mention that by industry standards, the overall size drill bit for a 1/4′′ 20 tap drill is a #7 drill bit with a 13/64” shank dimension. When you’re tapping tougher materials, I recommend you try using a 7/32” drill bit.

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About Brianna Goulet

Brianna is a freelance writer who covers home decor, DIY projects, and tool reviews. She’s written for a variety of sites on these topics. She's originally from Massachusetts but she's currently living in Florida.

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