Okay, so here’s a story. One afternoon, I was all set to install some brackets for a shelf in my garage. I’d picked out 10-32 screws because they were perfect for the job. I marked the spots, got my drill, and started tapping. But guess what? I used the wrong drill bit size.
Yep, I ended up stripping the threads, and the whole thing was a mess. I had to fill the holes, wait for them to dry, and start all over again.
That day taught me a big lesson: using the right drill bit for the right tap size matters—a lot. So if you’re wondering What Size Drill Bit for 10-32 Tap, you’re in the right place. I’ll explain everything in plain English, share real-life examples, and make sure you don’t make the same mistakes I did.
Article Summary
- What Does 10-32 Even Mean?
- The Golden Answer: What Size Drill Bit for 10 32 Tap?
- Why the #21 Drill Bit Works Best
- Can You Use a Different Drill Bit? (Yes, But…)
- How to Drill and Tap for a 10-32 Screw: Step-by-Step
- Pro Tips I Learned the Hard Way
- Common Projects That Use 10-32 Screws
- What Materials Work Best for Tapping?
- What Size Drill Bit Should I Use for a 10/32 Tap?
- What Size Drill Bit Do You Use for 10 32 Tap?
- FAQs On What Size Drill Bit for 10-32 Tap
- Final Thoughts: Drill Smart, Tap Right
What Does 10-32 Even Mean?
Before we jump into drill sizes, let’s break down what “10-32” means.
- “10” refers to the screw size. In this case, it’s a number 10 screw.
- “32” tells us there are 32 threads per inch (TPI).
So a 10-32 screw is a #10 diameter screw with fine threading. These are super common in electronics, automotive work, and even furniture.
The Golden Answer: What Size Drill Bit for 10 32 Tap?
To tap a hole for a 10-32 screw, you need a #21 drill bit, which is 0.159 inches in diameter.
| Tap Size | Threads Per Inch | Drill Bit Size | Decimal Inches |
|---|---|---|---|
| 10-32 | 32 TPI | #21 | 0.159″ |
This size gives you enough material around the threads to bite into while making it easy to drive the screw.
Why the #21 Drill Bit Works Best
The goal is to have enough material left after drilling so your threads cut nicely but don’t strip.
- Too small of a hole = the tap might break (been there!)
- Too large of a hole = your threads won’t grip well
The #21 bit hits the sweet spot.
Can You Use a Different Drill Bit? (Yes, But…)
Sometimes I don’t have the exact bit on hand. If you’re in a pinch, you might wonder if you can use something close.
Let’s compare:
| Drill Bit | Decimal Size | Should You Use It? |
| #20 | 0.161″ | Too big, threads may not hold |
| #22 | 0.157″ | Slightly small, risky |
| 5/32″ | 0.15625″ | Too small, might break tap |
If you’re not using a #21, #22 is the safest alternative, but you’ll need to tap carefully.
How to Drill and Tap for a 10-32 Screw: Step-by-Step
Here’s how I do it when I want it done right:
Step 1: Mark Your Hole
Use a center punch to keep the drill bit from wandering.
Step 2: Drill the Hole
Use your #21 drill bit and go straight in. If you’re working with metal, go slow and use cutting oil.
Step 3: Tap the Hole
Use a 10-32 tap. Hold it perpendicular and turn slowly. Every full turn, back off a quarter to break chips.
Step 4: Clean Out the Threads
Use compressed air or a pick to remove debris. Don’t just blow it with your mouth—ask me how I know.
Step 5: Test the Fit
Thread in a 10-32 screw. It should go in smooth, not too tight and not too loose.
Pro Tips I Learned the Hard Way
- Use a tap handle. Pliers make it easy to go crooked.
- Don’t force it. If it’s not going in, something’s wrong.
- Wear safety glasses. Tiny metal shavings love to fly into your eyes.
Common Projects That Use 10-32 Screws
If you’re wondering whether this info even matters, here are places where a 10-32 tap comes in handy:
- Mounting PC hardware like fan brackets or drive trays
- Electrical boxes for securing cover plates
- Automotive work, especially license plate brackets
- Home improvement, like towel racks and wall fixtures
I use 10-32 screws all the time, especially when working with sheet metal or aluminum.
What Materials Work Best for Tapping?
Tapping works differently depending on what you’re drilling into.
| Material | Drill Speed | Lubrication Needed | Difficulty |
| Aluminum | Medium | Yes | Easy |
| Mild Steel | Slow | Yes | Moderate |
| Stainless Steel | Very Slow | Yes (essential) | Hard |
| Plastic | Medium | No | Easy |
Tip: The harder the material, the more likely the tap will break if you rush.
What Size Drill Bit Should I Use for a 10/32 Tap?
When I first tried to tap a hole for a 10-32 screw, I had no idea what size drill bit to grab. I remember standing in my garage, holding a handful of bits, totally confused. I didn’t want to mess it up and strip the threads—or worse, break the tap.
So, after a little digging (and some trial and error), I found the sweet spot.
👉 You need a #21 drill bit for a 10-32 tap.
It’s that simple.
The #21 bit gives you the right hole size for tapping clean, crisp threads without putting too much strain on the tap. It’s not too tight, not too loose—just right, like Goldilocks would say.
Here’s a quick tip I wish I knew earlier:
- If you don’t have a #21 bit, a 5/32-inch drill bit can work in a pinch. But be careful—it’s slightly smaller, so the tap might bite harder and could break in tougher materials.
Whenever I use the #21 drill bit with some cutting oil, my taps glide in like butter. No squeaking, no snapping, and the threads turn out super clean.
If you’re working with metal, always take it slow and steady. I learned that the hard way by snapping a tap inside a steel bracket. Not fun. 😅
What Size Drill Bit Do You Use for 10 32 Tap?
I’ve been asked this a few times by friends doing small repairs or building projects: “Hey, what size drill bit do you use for a 10-32 tap?” I always give the same answer.
💡 Use a #21 drill bit.
That’s the size you want if you’re tapping for a 10-32 thread.
Let me break it down a bit more, especially if you’re new to tapping threads:
- “10” refers to the screw size (it’s a #10 screw).
- “32” means it has 32 threads per inch (that’s pretty fine).
- The #21 drill bit, which is 0.159 inches in diameter, makes just the right hole for the tap to cut those fine threads.
Why does the size matter? Well, I once used a bit that was too big. The screw went in, but it felt loose, like it wouldn’t hold under pressure. Then I tried a smaller bit, and bam—tap broke halfway in. Trust me, pulling a broken tap out is a nightmare.
Now I just keep a #21 drill bit labeled “For 10-32” in my toolbox. I even wrapped a little tape around it to make it easy to spot. It saves me time and stress every time I need to tap that size.
And here’s something cool: the 10-32 tap is pretty common in electronics, car mods, and even some furniture hardware. So once you get the drill bit size right, you’ll feel more confident working on all kinds of stuff.
FAQs On What Size Drill Bit for 10-32 Tap
Q: Can I use a 5/32 drill bit for a 10-32 tap?
A: Technically, it’s close. But it’s a little too small and might make the tap bind.
Q: What happens if I drill too big?
A: The screw might not hold. You could try using a thread insert, but it adds extra work.
Q: Can I use a cordless drill to tap the hole?
A: Please don’t. It’s too fast and too risky. Use a hand tap instead.
Q: How deep should I drill?
A: At least 1.5 times the screw length, if you can. That way, the screw holds strong.
Q: Do I need a pilot hole?
A: Not if you’re using the correct tap drill size. The #21 is your pilot hole.
Final Thoughts: Drill Smart, Tap Right
If you take away just one thing from this article, let it be this: use a #21 drill bit when tapping a 10-32 hole.
That tiny detail can make or break your project—literally. Whether you’re mounting a bracket, installing hardware, or doing a quick repair, getting the size right makes the job smooth and stress-free.
I learned it the hard way, but you don’t have to. Next time you grab a 10-32 screw, you’ll know exactly what drill bit to pair it with.