What Size Drill Bit for 1/16” NPT Tap?

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The 1/16” NPT tap is a common tap mainly used for general machine tapping or CNC tapping. 1/16” NPT taps are generally made of steel. They are one of the smallest pipe taps you can use. If you want to know what size drill bit for a 1/16” NPT tap is, read further.

What Size Drill Bit for 1/16” NPT Tap?

A 1/16” NPT Tap needs a size D drill bit or 0.2460 inches in decimals. NPT taps are also called pipe taps and don’t confuse them with NPTF taps and tapered taps like the 5-40 tap.

Hand drilling a hole in metal work

1/16” taps are commonly used for tapping pipe fittings and couplings much like the 1/8″ NPT tap unlike the 2″ NPT with a bit size of 2 7/32″ which deals with larger threadings. They are applicable to a lot of materials in through or blind-holed conditions.

To know if you are actually using a 1/16” NPT tap, you can refer to the following specifications (for carbon steel pipe tap only):

  • Size: 1/16-27 NPT
  • Material: Carbon Steel
  • Finish: Uncoated (Bright)
  • Style: NPT
  • Cutting Direction: Right Hand
  • Tap Size: ⅛ NPT27
  • Number of Flutes: 4
  • Thread Length: 11/16
  • Overall Length: 2-⅛
  • Shank Size: 0.3125
  • Matching Drill Bit: D or C
  • Flute Type: NPT

Tips for Using Medium Drill Bits

Consider Using Stud Finder

A stud finder ensures you are not drilling into a water pipe or electric cables. Drilling through electric cables can create a huge accident, like electrocuting yourself. So, it’s best to use a stud finder as a safety precaution.

It’s also useful to avoid hitting water pipes which can cause leakage and flooding in your home. You should use a stud finder when drilling with hazardous materials near the drilling spot.

If you’re drilling into an unfamiliar surface, it’s best to use a stud finder to ensure you are drilling precisely and accurately. It’s better to be safe than sorry.

Drill bits all lined up in its red container

Deburr the Hole

Most medium drill bits are used for drilling holes. So, deburring the hole is a sensible thing to do. After you’re done drilling, make sure the hole does not have sharp edges or burr left in the hole. Feel the hole until it’s smooth.

It ensures your hole is smooth and clean, so you produce quality work. You can deburr a hole by running it in a bit of power and running the bit around the edges of the hole.

You can also use deburring tools to make the process simpler and easier. Most of them come with an instructional, so you should have no problems learning to properly use them.

Rely on Drill Guides If You Have Low or No Vision

You can buy drill guides built for medium drill bits from hardware stores. It makes drilling with medium drill bits easy as the guide will accurately place the bit into your workpiece.

If you have a drill press, you can make a set of drill guides by drilling holes with medium-sized diameters into small blocks of wood. It’s like a DIY drill guide that you can use to better your drilling accuracy. 

If you can’t do either of the two options, you can ask a friend to help you make drill guides using your drill and a built-in level.


1/16” NPT taps need a size “D” drill bit and can be used for a wide variety of materials. They’re mostly used as a hand threading tap. If you’re going to use them, use a sealer for the threads for them to work properly.