10-32 Tap Drill Size

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If you’re knee-deep in a project and scratching your head about which drill bit and tap size to use? You’re in luck because you’ve landed on the right page. 

Trust me, getting the 10-32 tap drill size spot on can be a game-changer. I’ve been there, so let me share the lowdown on how to pick, calculate, and nail that 10-32 tap drilling. Let’s dive in!

What is the Drill Bit Size for a 10-32 Tap?

The correct drill bit size for 10-32 tap is a #21 drill bit. The fractional drill bit measurement is 5/32”. 

10-32 drill bit and screw

The drill bit size for 10-32 taps is entirely different because they come in two different thread counts. It may be hard to remember and memorize. That is why helpful sizing charts of tap drills are created for that. 

How to Determine the Drill Bit Size for a 10-32 Tap

Determining the size of a 10-32 tap drill begins with understanding the difference in tap size.

After figuring out the dimensions, it will now be easier to figure out which size will work suitably with the tap size you are working on.

10-32 Sizing

To ensure the proper functionality of 10-32 taps, it is essential to adhere to specific parameters and perform dimensional verification. Here’s how you can achieve this:

using a 10-32 Tap
  1. For sizing, you need to accurately count the diameter of the tap, the percentage of screws you need, the pitch, and the hole size.
  2. The thread percentage is not related to the size of the tap. It depends on the result.
  3. Thread content is typically between 75% and 85%, but our recommendation is 80%.

Once you have completed your desired measurements, you may now calculate the drill bit size you need to use.

How Can You Calculate the Size of the Tap Drill?

To calculate the tap size, you need to be familiar with the basic calculations and the tap size you are using.

1. Measure the diameter of the tap or read the number given in the tap specifications.

2. Then substitute the diameter value into a simple formula. H. DH = DMB-0.0130 (% of all required screws / Ni). 

tap drilling

Here, the DMB serves as the diameter, and Ni is the other tap part.

3. Then insert a value with a thread size of 10-32 and compute for the DH.

4. You will find that the answer fits well with the #21 drill bit size.

You can use the formula above to compute the drill size for any tap measurement. Make sure the number of threads is between 75% and 85%. 

How Come 10" and 32" Tappings Require Different Sizes?

You may wonder why you need different sizes for 10 and 32 taps. To better understand, you need to know the difference between the two.

tap drilling with a clamp

If the holes are not sized correctly, not only will the machine not work properly, but it will not work.

How to Drill With 10-32 Taps

Now that all the calculations are in place, it’s time to drill with 10-32 taps.

Drill Bit Size for a 10-32 Tap
  1. Take all the measurements you have and choose the best suited drill bit size.
  2. Be sure to put material in the clamp to prevent sudden slippage, rotation, or injury.
  3. Put the masking tape to the material you’re working on to allow enough space to mark where to make the holes.
  4. Set the drill at 90 degrees and check closely if it is vertical to the metal [1]. Even a slight tilt can cause the hole to be crooked.

I highly recommend drilling first with a scrap metal to prevent irreversible damage. It also helps prevent sudden accidents and gives you confidence before the final drilling process.


What is the clearance hole for a 10-32 screw?

The clearance hole for a 10-32 screw is 0.1900. This diameter is small enough for the screw to make new threads and large enough for the tap to fit in. Creating the wrong size of clearance hole can ruin your whole project.


If you’re stucked in the middle of a project because something didn’t fit just right? That was me when I didn’t know the importance of the 10-32 tap drill size. A tiny miscalculation or, even worse, skipping the math entirely can lead to a mess. 

It’s like trying to fit a square peg in a round hole! So, always stick to the formula and measurements you have. It’ll save you from a lot of headaches and wasted effort. Don’t learn it the hard way like I did!

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Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You’ve probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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