What size drill bit do I use for a 1/8 NPT tap?

Tap size	Threads per inch	Drill size w/ taper pipe reamer
1/8	27	21/64
1/4	18	27/64
3/8	18	9/16
1/2	14	11/16

Consequently, how do you drill a hole in a 1/8 NPT?

For a 1/8 npt tap requires an "R" drill. Run your tap into the hole to the depth of the threads on the tap. Use a 1/8 fitting as a thread gauge to insure you have enough threads.

Subsequently, question is, how do you drill a 1/4 NPT tap? National Pipe Thread Taper ( NPT ) is a U.S. standard for tapered threads used on threaded pipes and fittings .

TAPER PIPE SIZES - NPT
TAP SIZE	DRILL SIZE
1/4-18	7/16
3/8-18	37/64
1/2-14	23/32

Similarly, you may ask, what size hole do you drill for a 1/4 tap?

You can get away with a 1/8 inch drill for a 1/4-20 tap in a pinch.

What size drill bit do I need for a 8 32 tap?

To Tap This Size Screw Or Bolt:	Use This Drill Bit:	Decimal Inches
4mm-0.75mm	3.4mm	.1338
8-32 NC	#29	.1360
8-36 NF	#29	.1360
8-40 NS	#28	.1405

38 Related Question Answers Found

What size of drill bit do I need for a 1/8 NPT tap?

Tap size	Threads per inch	Drill size w/ taper pipe reamer
1/8	27	21/64
1/4	18	27/64
3/8	18	9/16
1/2	14	11/16

What size drill bit should I use?

Use a bit 1/64” smaller than the target hole size for softwoods. Use a bit exactly the same size as the hole when working on other materials. If you're not sure which to select, choose a drill bit 1/64” larger than the hole you wish to create.

How deep should a NPT tap go?

To do it right, you need to use a tapered reamer on the holes before you tap them to get a full thread. That's a tough one. You really need a plug gauge to be accurate. You can get fairly close by going to a depth of about 2/3rd's of the thread length of the tap.

What does NPT stand for?

National Pipe Tapered

What is an R drill bit?

Drill bit "R" is .339" in diameter. Hope that helps. danc46 , 09-14-2007 04:39 PM. It's smaller than the Q drill bit and larger than the S drill bit.

How do you drill and tap a 1/4 20 hole?

How to Drill & Tap for a 1/4-20 Bolt

Measure the location needed for the 1/4-20 tapped hole.
Set the point of the center punch on the location of the hole to be tapped.
Insert the drill bit into the drill.
Apply pressure to the drill.
Insert the 1/4-20 tap into the tee handle.
Attach the flapper wheel to the grinder.

What size drill bit do I use for a 5/16 tap?

OBW0549. Looking at the "Tap Drill Chart" section at the bottom, they recommend an "F" drill for a 5/16"-18 fastener. Then, looking up above at the "Decimal Equivalent Chart" section, an "F" drill measures 0.257", about halfway between 1/4" and 17/64".

What is the drill size for a 3/8 tap?

For example, the tap drill for 3/8-16 is 5/16. 3/8 - 1/16 = 5/16. For other sizes that don't work out so nicely, just use the closest drill size.

What size is a #6 drill bit?

Drill sizes to 1" diameter

Drill sizes to 1" diameter Legend Fractional Inch Letter Drill Millimeters Number Drill
Millimeters	Inches	Designation
5.1054mm	.201"	# 7
5.1594mm	.203125"	13/64"
5.1816mm	.204"	# 6

What size drill bit to pre drill for a #10 screw?

Drill bit sizes for pre-drilling (most commonly used sizes in bold)

Screw Size	Pilot hole size for hardwoods*	Pilot hole size for softwood**
#9	1/8	3/32
#10	1/8	7/64
#11	5/32	9/64
#12	9/64	1/8

What size is a 7 drill bit?

#7 is a 0.201" diameter bit, 13/64" is 0.203" diameter.

What are the 3 types of taps?

There are two types of Hand Taps:

Taper Tap. A taper tap has quite a lot of taper to help it ease into cutting threads gradually.
Bottoming Tap.
Plug Tap.
Spiral Point Taps (Gun Nose or Bull Nose Taps)
Spiral Flute Taps or Gun Taps.
Interrupted Thread Tap.
Pipe Taps.
Form or Roll Taps (Thread Forming Taps)

What is a number 7 drill bit?

There are three standard sets of drill bits. Fractional, Number and Letter. A typical Number (or "wire gauge" ) bit set is numbered from 1 to 60. #7 is just barely smaller than 13/64", but quite a bit bigger than 3/16"

What is a taper pipe reamer?

Hand - Tapered-Pipe Reamers. Taper Pipe Reamers are multi-fluted, end cutting tools used to resize and clean up previously formed holes prior to tapping. Taper is 3/4" per foot.

What is NPT fitting?

NPT stands for National Pipe Tapered thread. It is also sometimes called National Pipe Thread, NPTF (F for Fuel), American Standard Taper, or simply "pipe". Most other plumbing fittings have straight or parallel threads, but NPT fittings have a tapered thread profile.

What size is an R drill?

Drill Bit Size Chart

Size	Decimal Equivalent	Size
.36 mm	0.0142	R
79	0.0145	8.70 mm
.38 mm	0.015	11/32"
1/64"	0.0156	8.75 mm

When would you use a plug tap?

There are times when a Plug tap can be used to start a thread without using a taper tap first if the Plug tap is started with a guiding center or fixture. In blind hole applications, Plug taps are used after a Taper to get closer to the bottom of the hole. Bottoming tap have a 1.5 thread chamfer.