Is 1/8"-27 and 1/8" NPT the same? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Xandy Boosts · 01-25-2008, 04:57 PM

Bought a tap and die kit. The only 1/8" one says 1/8 - 27. Are they the same? I need to tap out my bleeder screw to 1/8" NPT. I tried google but didn't come up on much. Thanks guys appreciate it.

*brndck* · 01-25-2008, 04:59 PM

bleeder screw for what?

Xandy Boosts · 01-25-2008, 05:01 PM

For Coolant Breather Tank....

*brndck* · 01-25-2008, 05:04 PM

pretty sure it should be the same. like 90% sure.

Xandy Boosts · 01-25-2008, 05:05 PM

Yea I'm trying to find something I can tap for fun to see if it fits myself but all I can find are thin ass tin cans and prescription bottles lol. gotta dig deeper

Sir · 01-26-2008, 05:38 AM

IIRC,
BSTP is 1/8-28
NTP is 1/8-27
the one thats 1/8 is just straight thread.

GSXRJJordan · 01-26-2008, 06:22 AM

I thought NPT was tighter, like 40-something? That might just be on the bigger stuff, but I doubt it.

Also, the difference between BSPT and NPT is the taper, not just the pitch. They're definitely not compatible, even though they seem close.

ej2civic · 01-26-2008, 07:22 AM

NPT will have a taper downward, not sure on the thread itself but the first thread will be smaller around than the outside, They do they so it doesn't have to be tight yet it will still seal

Def · 01-26-2008, 07:10 PM

Yes, 1/8" NPT is 1/8-27. It's easy to see if the thread tapers as well by looking at the root of the thread on the tap.

01-25-2008, 04:57 PM	#1
Xandy Boosts Zilvia FREAK! Join Date: Dec 2004 Location: Long beach Age: 39 Posts: 1,003 Trader Rating: (2) Feedback Score: 2 reviews	Is 1/8"-27 and 1/8" NPT the same? Bought a tap and die kit. The only 1/8" one says 1/8 - 27. Are they the same? I need to tap out my bleeder screw to 1/8" NPT. I tried google but didn't come up on much. Thanks guys appreciate it. __________________ it's a RUCKUS life

01-25-2008, 05:01 PM	#3
Xandy Boosts Zilvia FREAK! Join Date: Dec 2004 Location: Long beach Age: 39 Posts: 1,003 Trader Rating: (2) Feedback Score: 2 reviews	For Coolant Breather Tank.... __________________ it's a RUCKUS life

01-25-2008, 05:05 PM	#5
Xandy Boosts Zilvia FREAK! Join Date: Dec 2004 Location: Long beach Age: 39 Posts: 1,003 Trader Rating: (2) Feedback Score: 2 reviews	Yea I'm trying to find something I can tap for fun to see if it fits myself but all I can find are thin ass tin cans and prescription bottles lol. gotta dig deeper __________________ it's a RUCKUS life

01-26-2008, 06:22 AM	#7
GSXRJJordan Post Whore! Join Date: May 2006 Location: San Diego, CA Posts: 9,135 Trader Rating: (19) Rides Gallery: GSXRJJordan Feedback Score: 19 reviews	I thought NPT was tighter, like 40-something? That might just be on the bigger stuff, but I doubt it. Also, the difference between BSPT and NPT is the taper, not just the pitch. They're definitely not compatible, even though they seem close. __________________ Jordan Innovations has a new web site! www.JordanInnovations.com -- All your favorite FD Pro Drifters love it, trust me -- www.JordanInnovations.com

01-26-2008, 07:22 AM	#8
ej2civic Leaky Injector Join Date: Jun 2006 Location: Northern CT Posts: 105 Trader Rating: (0) Feedback Score: 0 reviews	NPT will have a taper downward, not sure on the thread itself but the first thread will be smaller around than the outside, They do they so it doesn't have to be tight yet it will still seal __________________

01-25-2008, 04:59 PM	#2
brndck Premium Member Join Date: Jun 2003 Location: torrance, ca Age: 43 Posts: 12,686 Trader Rating: (130) Rides Gallery: brndck Feedback Score: 130 reviews	bleeder screw for what?

01-25-2008, 05:04 PM	#4
brndck Premium Member Join Date: Jun 2003 Location: torrance, ca Age: 43 Posts: 12,686 Trader Rating: (130) Rides Gallery: brndck Feedback Score: 130 reviews	pretty sure it should be the same. like 90% sure.

01-26-2008, 07:10 PM	#9
Def Post Whore! Join Date: Apr 2004 Location: Houston, TX Posts: 2,701 Trader Rating: (16) Feedback Score: 16 reviews	Yes, 1/8" NPT is 1/8-27. It's easy to see if the thread tapers as well by looking at the root of the thread on the tap.