I have a 1/2" Black Iron Pipe Flange that I need to tap through. The goal is to have a pipe threaded through the flange and into another fitting. I have already made the mistake of ordering a standard 1/2" NPT tap (Drill America 1/2 in. -28 High Speed Steel Plug Hand Tap), which was both too small and fine threaded. Any ideas?
Tap for 1/2" Black Metal Flange
- Thread starter hunterc4
- Start date
TexMedium
Well-known member
If you are trying to tap THROUGH the flange, into another 1/2" fitting, bear in mind that most NPT pipe thread is tapered. You may not be able to get the assembly tight and leak free. Also, 1/2" NPT is 14 threads per inch, NOT 28!
Are you talking about tapping the four mounting holes in the flange, or the center pipe thread hole itself? Bolt hole thread and pipe thread are completely different. As already mentioned, pipe thread is tapered so if you're trying to thread one pipe into two fittings it probably won't work.
turnthewrench 2.0
Well-known member
dr_clyde
Well-known member
This.
The threads are tapered, what you are describing won’t work.
You may need to bore the flange to be a slip fit over the pipe OD, then weld the flange in the place allowing the threads of the pipe to stick through to where you can attach another fitting.
You’re not going to get two fittings (flange and elbow or whatever), on one set of threads. Sorry.
This is what I'm looking to do, and it sounds like y'all are saying I can't.
https://ibb.co/bJgw3Q7
https://ibb.co/bJgw3Q7
Last edited by a moderator:
dr_clyde
Well-known member
Linky no workie
You have to copy after the second https and paste it into the browser. It won't let me post a picture or link since I don't have 5 post (although i'm almost there just from this thread).
what is the application for?
you will need a running thread on the pipe (cut extra long) or if you can, tap the flange extra deep .
In either case, the joints won't be leak proof.
you will need a running thread on the pipe (cut extra long) or if you can, tap the flange extra deep .
In either case, the joints won't be leak proof.
dr_clyde
Well-known member
What is the application?
The pic shows a pipe threaded WAY longer than standard.
Not a standard NPT joint.
If this has to hold pressure you’re better off boring and welding the flange.
The pic shows a pipe threaded WAY longer than standard.
Not a standard NPT joint.
If this has to hold pressure you’re better off boring and welding the flange.
rlitman
Well-known member
Why not use a drop ear elbow for that?
rsanter
Well-known member
I see the image and that will not work with threads. You will need to fab something
59 wagon man
Well-known member
what are you trying to accomplish?
OK, so I opened up your link picture.
What that shows really won't work.
Pipe threads (NPT) are tapered (so that they can wedge tight and seal themselves).
A tapered male thread on the pipe can't really be tapered enough to thread into a female threaded NPT flange center hole and THEN also thread into a female threaded NPT elbow/fitting.
And as mentioned, a 1/2-28 thread is a UNEF thread and NOT an NPT thread. The standard thread for 1/2" pipe threads would be 1/2-14-NPT (which for the female threads would usually take a .45/64 drill before using the NPT tap).
And all that metal just 'hanging' from some 1/4" thick plywood? Nope.
What are you actually trying to accomplish here?
What that shows really won't work.
Pipe threads (NPT) are tapered (so that they can wedge tight and seal themselves).
A tapered male thread on the pipe can't really be tapered enough to thread into a female threaded NPT flange center hole and THEN also thread into a female threaded NPT elbow/fitting.
And as mentioned, a 1/2-28 thread is a UNEF thread and NOT an NPT thread. The standard thread for 1/2" pipe threads would be 1/2-14-NPT (which for the female threads would usually take a .45/64 drill before using the NPT tap).
And all that metal just 'hanging' from some 1/4" thick plywood? Nope.
What are you actually trying to accomplish here?
How about running a parallel die over pipe to correct length and taper die on end for fitting ? Both parallel pipe and pipe are 1/2-14 I believe.
https://www.amazon.com/dp/B008AR0UTQ/?tag=atomicindus08-20
https://www.amazon.com/dp/B008AR0UTQ/?tag=atomicindus08-20
ChevyEFI
Well-known member
Interesting. The BSPP would be smaller than the larger section of the NPT.
Would the NPT ****** end have dimensions that pass through the flange, and then seal properly at the elbow?
Conversely, if the flange were tapped deep, would the BSPP have enough thread engagement to matter?
Adjustable NPT dies are available.
?????????? I have no clue. We use alot of parallel pipe fittings at work with our hydraulics. Just a guess to look at a possibility of threading for both.
If it's being done to secure pipe to ceiling, could a weld style flange be used? You could slide it over the pipe and mount to ceiling without threading. To help secure you could drill and thread for set screws thru flange to pipe or weld. Some weld flanges have a pipe stop/lip that would have to be removed to slide the pipe thru.
matt_i
Well-known member
I believe there's an NPS standard which is not tapered. Just straight threads like a bolt. No idea how they seal.
What I would do rather than source oddball stuff is to bore out (rat-tail file, dremel tool, its not very large on a 1/2" pipe flange) the threads on the flange to a close clearance fit to the OD of the ******,or even higher on the taper, same concept. Then tig (or MiG) weld the flange on from the backside.
What I would do rather than source oddball stuff is to bore out (rat-tail file, dremel tool, its not very large on a 1/2" pipe flange) the threads on the flange to a close clearance fit to the OD of the ******,or even higher on the taper, same concept. Then tig (or MiG) weld the flange on from the backside.
510ebl
Well-known member
Would a black iron pipe stub-out work? As long as you are not expecting it to support an excessive vertical load?
https://www.fairviewfittings.com/pr...lack-iron-pipe-fittings/black-iron-stub-outs/
And for that “finished, but industrial” look:
https://www.argco.com/wall-plate-1-2ips-3-4cps-cast-iron-galvanized-w-set-screw.html
https://www.fairviewfittings.com/pr...lack-iron-pipe-fittings/black-iron-stub-outs/
And for that “finished, but industrial” look:
https://www.argco.com/wall-plate-1-2ips-3-4cps-cast-iron-galvanized-w-set-screw.html
Last edited:
If a standard stub out isn’t configured I made this to pipe compressed air to the basement. Standard pipe flange flange opened up using a boring bar on the lathe, weld prepped and TIG welded it. Provides a super solid anchor surface and doesn’t move when I plug it in. Easy 30 minute project that took longer for the paint to dry.
Sent from my iPhone using Garage Journal
Sent from my iPhone using Garage Journal
Mohawk Dave
Well-known member
Yes, there is NPS = National Pipe Straight.
This is what is used a lot for electrical: like into a J-box etc. That's usually always NPS.
I had to drill out and tap my big drill press cast iron base to run the power cord through it (it was mangled). I used a 1" NPS tap, and then screwed in a cord grip.
I know flex-tite conduit uses it too, and they have sealing washers on each side as, like you said, it is not tapered so it will not seal itself.
That's what I'm trying to do, but from a ceiling application. I was trying to avoid paying $26 for a RapidAir fitting. Since I don't have a welding machine, I think the Wardflex 381 appliance stubout is my best bet. If I had to do it over again, I would probably have ordered the RapidAir fitting. But at least I learned a lot.
jg4660
Well-known member
It looks like your using the flange as a way to support the weight of the pipe, if so there are easier ways than this. research standard pipe hangers.
JG
JG
stokefire7
Well-known member
- Joined
- Oct 5, 2011
- Messages
- 616
It's called a running thread.
Leaflessshadetree
Well-known member
Why not just run the pipe through and put an escutcheon plate to clean up the hole where it passes through?