What Size Drill For 3/8 Npt Tap

Hey there, buddy! So, you're in a pickle, huh? Got a 3/8 NPT tap and no clue what size drill to use? Fret not, we're gonna sort this out over a virtual coffee. Let's dive in!

First things first, what's NPT?

Alright, don't roll your eyes at me. NPT stands for National Pipe Taper. It's a threading system that's been around since the 1800s. You'd think they'd come up with a snazzier name by now, right? But no, we're stuck with NPT.

Now, back to that drill size

You're dealing with a 3/8 NPT tap, which means you need to drill a hole that's just the right size for the tap to fit into. The tap's gonna cut threads into your material, so you need a pilot hole that's slightly smaller.

Here's where it gets a tad tricky. The drill size you need depends on the material you're tapping. But don't worry, I've got a handy little cheat sheet for you.

Drill sizes for common materials

• Steel, Cast Iron, or Bronze: You'll want a 11/32 inch drill. That's right, it's not a typo. It's a weird size, I know. But that's what the tap gods demand.
• Aluminum or Plastic: For these materials, you'll need a 7/32 inch drill. See, I told you it'd get easier.

Now, you might be wondering, "What if I don't have the right drill bit?" Well, my friend, you've got a couple of options.

Npt tap drill size chart - stattropical

When in doubt, oversize

If you've only got a drill bit that's a bit too big, don't panic. You can still use it, but you'll need to be careful. Drill the hole, then use a tap that's one size smaller than your 3/8 NPT tap. It's not ideal, but it'll get the job done.

Or, you could be like me and just run to the hardware store for the right drill bit. I mean, who wants to deal with that tap drama, right?

Npt Tap Drill Size Chart - Coloring & Charts Printable

One last thing

Before you start drilling, make sure your drill bit is sharp. A dull bit can ruin your material and give you a headache. Trust me, I've been there. It's not pretty.

Alright, buddy, that's all I've got for you. You're now a tap-drilling pro. Go forth, make holes, and don't forget to wear your safety glasses. Your mom would want you to.