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Thread: 1/8 IPS Thread ???
05-29-2009, 10:38 PM #1
1/8 IPS Thread ???
I searched but couldn't find anything. This must have come up before so forgive me. Lamp fixtures apparently use a straight pipe thread. I have looked in some of my machinist books (I'm an amateur homeshop guy) and can't find much. I want to drill and tap a hole for a lamp fixture nipple. The nipple is about 0.386 inches in diameter measuring across the tops of the threads.
At my local Ace HW they show the designation for these nipples as 1/8 IPS. I believe the TPI is 27. Does the IPS stand for Iron Pipe Straight? I'm not familiar with pipe thread designations and can't figure out the 1/8 either. What on earth does this stand for?
Do I want to buy a 1/8 NPS tap to tap this guy and therefore a tap drill "S"?
Thanks in advance.
05-29-2009, 10:56 PM #2
"I" = internal?
P = pipe - but you prolly already got there eh?
S = strait
I'm not familiar with pipe thread designations and can't figure out the 1/8 either. What on earth does this stand for?
W/O looking - yes - 1/8NPS is likely a letter S. (National Pipe Strait.)
Also - 1/8 pipe is 27 TPI.
While it is great that the local hdwr was able to help you out like this - you can save yourself many future haertaches (attacks?) by NOT buying hdwr quality cutting toys! And I kant stress this nearly enough when it comes to TAPS! They can be used succesfully in thread repair - but not for cutting new. (Your milage may vary.)
Think Snow Eh!
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05-29-2009, 11:37 PM #3
Okay, but if 1/8 means 1/8" what does this refer to? Clearly the inside diameter of this is greater than 1/8". The S tap drill is 0.3480 inches, so I still don't understand the nomenclature of 1/8. Can you help or point me to an explanation?
Oh, are you saying that the internal diameter of the male nipple is 1/8"??? That must be it. Am I right?
Last edited by 11B4VLA; 05-29-2009 at 11:42 PM. Reason: A second thought
05-29-2009, 11:44 PM #4
05-29-2009, 11:57 PM #5
So Vance, why do you think google did not find IPS? Can you show me a query that will get that? A discussion on the Home Machinist board opined that it meant Iron Pipe Straight. Are your responses always so helpful or did you just pick me on a bad night?
If it is so straightforward why don't you post a link to the definition of IPS?
Thanks for very little other than entertainment.
05-30-2009, 12:11 AM #6
Art, I googled this for you http://www.sizes.com/materls/lampFit.htm and this http://en.wikipedia.org/wiki/Nominal_Pipe_Size and this http://chestofbooks.com/crafts/mecha...ron-Pipes.html
All of the above were googled in 15 seconds and there's much much more.
05-30-2009, 12:14 AM #7
IPS = Iron Pipe Standard (not straight).
05-30-2009, 12:51 AM #8
Good Links, Thanks
Carl and Professor: Very interesting links. BTW, Professor, your link says that IPS is Iron Pipe Size not Iron Pipe Standard. So no wonder I couldn't measure anything that is 1/8" since the designation is historical and not current by measurement.
So I think that I would be correct in using a non-tapered NPS 1/8-27 tap and an "S" drill as the tap drill. According to
Okay, then, I think I get it.
05-30-2009, 10:29 AM #9
You've got it right on your tap and drill size, you could also use a 11/32 drill bit if you currently have one without buying a S drill if don't have one of these.
I find google to less and less usable (for me), if you type in IPS, standard for IPS you get all kinds of crap before you find anything referring to Iron Pipe Size. After all there are a lot of acroymns that use IPS which none meaning Iron Pipe Size.
Pipe sizes and their designations along with the proper taps can get confusing, since many of us and others have probably been around since the original IPS (Iron Pipe Size) standards. A lot of times we create our own standard based upon the new and the old ie., IPS (Iron Pipe Straight) vs the newer NPS as defined below.
The problem with standards as once you get use to using it, then along comes some newer standard that tries to narrow the window by adding more standards. Pipe sizes are roughly denoted based on the ID, however it's the OD that remains the constant. Example: Schedule 10, 40, 80, 120 all have the same OD, while their wall thickness varies due to the pressure they can handle. 1/8 inch pipe is really the odd duck when it comes to pipe size since even at schedule 80 it's ID is almost a 1/4" in diameter. The number of threads is the easiest (for me) to tell the difference 1/8 and 1/4 inch pipe, 27 vs 18.
Ok, so much for the hot air I am blowing today.
American National Standard Pipe ThreadsNPT: National Pipe Taper Thread A sealant compound or Teflon tape must be used for a leak-free seal.British Standard Pipe Thread
FPT: female (internal) National Pipe Taper threads
MPT: male (external) National Pipe Taper threads
NPTF: Dryseal American National Standard Taper Pipe Thread No sealant is needed for a seal.
NPS: American Standard Straight Pipe Thread Used for mechanical joining -- holding a fitting in place. An O-ring or a metal seal is required.
NPSF: Dryseal American National Standard Straight Pipe ThreadBSPT: British Standard Pipe Taper threads
BSPP: British Standard Pipe Parallel (straight) threads
05-30-2009, 11:35 AM #10
I thought you were intelligent or interested enough to follow my suggestion and Google "pipe size" in order to answer your question. Sorry I was wrong.
I took the time to try it myself and found the first hit contained more than most people would want to know about pipe size:
03-21-2012, 07:18 AM #11
Condescending reply, ignorance of the subject, and poor spelling!
Your post is loaded with grammatical and spelling mistakes. I counted no less than 10 of them. Maybe you should learn to write before dispensing criticism.
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03-21-2012, 07:29 AM #12
03-21-2012, 08:04 AM #13
As far as any spelling errors incurred by Ox, the knowledge and experience he brings, outweighs your good grammar and spelling. Not everybody has IeSpell (or similar) loaded on their PC.
03-21-2012, 08:17 AM #14
The diameter on a pipe thread refers to the approximate hole diameter of the pipe. It's the hole diameter on a pipe that's important so that's the diameter that's used when specifying a pipe thread. The pipe OD will depend on the pipe wall thickness and must sometimes be turned to size.
03-21-2012, 08:23 AM #15
03-21-2012, 08:26 AM #16
FWIW - I saw this thread pop to the top and saw that I has replied to it once upon a time, so I checked it out to see...
I read my reply and thought that sounded a bit harsh. Not sure why I did that. ???
And then to find that the only reason that a 3 year old thread had surfaced was to bitch at me about it?
After re-reading my reply a cpl more times - trying to figger out why I werded it that way, I don't think I meant it in nearly a condecsending way as it appears. I think I must have been more in shock as to think that someone on a machine shop forum would not be familier with the 1/8" pipe designation?
I don't know - just guessing as I didn't use any emoticons that day - I kant be sure anymore either.
My speling and gramor aint neccessarilly dun in error BTW.
Last edited by Ox; 03-21-2012 at 09:35 AM. Reason: added a wee bit more
03-21-2012, 08:39 AM #17
With groing use of the internet, I began to see how common it is to find mispellings and improper grammar. It doesn't mean I critisized anyone about it though. If you want to make a real gripe, complain about spell checkers, cell phones and texting, etc., as they are making younger generation dumb as hell on that subject. And I have seen stupid errors on formal documents, where they most of all should not be
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03-21-2012, 08:48 AM #18
03-21-2012, 08:48 AM #19
Maybe Engineeringtech is yet another alias of "He who shall not be named", Queens, NYC lawyer, here to: stir the pot; raise a stink; start a shit storm; etc.
03-21-2012, 09:21 AM #20
Actually - for most common sizes and schedules, the OD's remain the same, and the ID's change with the wall thickness. But yes, the "sizes" are relative to the bore, although 1/8 pipe has always seemed to me to be far from 1/8" bore. (shrug)
It seems that pipe starts to use OD size referance @ 14" for some reason tho. ???
I am Ox and I approve this h'yah post!