10-32 Tap Drill Size

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If you find yourself working on a project and need to know the right drill bit and tap size, you are on the right page. Finding the correct 10-32 tap drill size for whatever you’re working on is crucial. 

So, our team identified how to determine, calculate, and drill 10-32 taps. Read on!

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

Thread sizes of 10-32 taps require specific parameters and dimensional verification. Here’s how to do it:

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.

We 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.


Knowing the 10-32 tap drill size is crucial to keeping your project on the right track. Doing wrong calculations or not doing any calculations at all can give you the wrong size resulting in wasted resources and effort. 

Therefore, closely follow the formula above and the dimensions available to finish the project correctly.

Robert Johnson is a woodworker who takes joy in sharing his passion for creating to the rest of the world. His brainchild, Sawinery, allowed him to do so as well as connect with other craftsmen. He has since built an enviable workshop for himself and an equally impressive online accomplishment: an extensive resource site serving old timers and novices alike.
Robert Johnson
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