When working with screws, each one needs a specific tap to make threads fit perfectly. But here’s the catch: before you even get to the tap, you need to find the right drill size.
Trust me, every tap has its match, and nailing that is key! I’ve learned all about the 6-32 Tap Drill Size, and I can’t wait to share the ins and outs with you. Ready to dive in? Let’s go!
Drill Bit Size for a 6-32 Tap
The 6-32 tap is one of the most commonly used taps. It is perfect for creating brand new threads or cleaning out damaged ones in a previously tapped hole. This type of tap features taper threads at the end, which help guide it within the hole.
The correct drill bit size for a 6-32 tap is No.36, with a decimal equivalent of 0.1065. You’ll need to take note of the correct drill bit size to get the best outcome.
How to Find Out the Drill Bit Size for a 6-32 Tap
6-32 Sizing
A 6-32 Thread Tap sizing includes close and free fit sizes. The close fit size for a 6-32 tap is 27, with a decimal equivalent of 0.1440.
On the other hand, for the free fit size, it should be 25, with a decimal equivalent of 0.1495. Note that this sizing applies to aluminum, copper, bakelite, cast iron, or any thin materials. Also, I suggest that you use one drill size larger.
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Calculating the Size of the Tap Drill
1. You’ll need to measure the overall diameter of the tap you want to use.
2. Then, use this formula– Dh = Dbm — 0.0130 (your desired entire thread percentage/ Ni). Note the following terms:
- Dh refers to the size of the drilled hole in inches.
- Dbm refers to the thread's basic major diameter.
- The "percentage of the full thread desired" depends on your preference. But, I suggest using 70 to 85 percent, based on your materials.
- "Ni" refers to the figure of inches in every thread.
3. Apply the figures based on the formula with a thread of 84 percent (for example).
4. Then, find the closest tap drill bit size using 1/16ths of an inch. Multiply the figures from the formula by 16.
Note: If the drill bit size you get is too undersized, determine the correct size of the drill bit in 32nds per inch. So, instead of multiplying the figure by 16, you will multiply it by 32.
Why Do 6" and 32" Tappings Require Different Sizes?
The 6″ and 32″ tappings require different sizes because of the close fit and free fit clearance hole, which applies to all materials.
As mentioned earlier, the close fit drill size for a 6-32 tap is 27, while the free fit drill size is 25. The clearance allows the tap to adjust and fit in the drill perfectly.
How to Drill With 6-32 Taps
1. To drill with 6-32 taps, you need to determine the diameter of the drill you will use.
2. Secure the blade and the clamp and hold the drill with the clockwise rotation. You can add a bit of oil to the thread for smoother drilling.
3. Then, point the thread tap on the surface you want to drill and slowly go through the material to make a hole. We suggest not using the clutch all the time. If you need to stop the drill, do it, then go one again.
4. Move the drill forward and backward until you entirely make the holes.
FAQ
What is the diameter of a 6-32 tap?
The diameter of a 6-32 tap is 0.1380 inches with a tap drill size of No. 36. Here is a tap drill sizing chart online that you can refer to if you’re unsure about the sizes and measurements.
Conclusion
Taps are commonly used to cut threads for screws [1] and bolts into plastic, wood, or metal. So, a hole for a specific size is required for the tap. Also, an improper drill bit size would not let the tap fit in the hole.
And as detailed above, the 6-32 tap drill size must be No. 36. You can use it for iron, stainless steel, aluminum, brass, copper, plastic, bronze, and nickel-based materials.
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.
