Threading black pipe

[jproaster]

Threading 3/4" black pipe from Lowes to make a tv stand.
Never threaded before...having some issues.
Using an old Rigid ratchet (in good shape) and Rapid Tap oil.
Threads look good, (not perfect) but the couplers from Lowes don't want to screw on easily. Sometimes will not thread.

Thoughts?

John

 

[The Cobbler]

either you're not threading deep enough or your die is out of adjustment.

 

[Chris705]

Make sure to back off the cutter several times when cutting the threads. And start by beveling the edge of the pipe with a grinder to allow the cutter to get a good start in cutting the threads.

 

[95vette]

Thread the pipe till there is one thread past the die, use plenty of oil.

 

[mrobins297aaa]

try a piece of store bought pipe into the lowes couplers if it threads in easy then there's a problem with your die...........if not then get some new couplings

 

[jproaster]

Lots of wisdom shared. Thanks all. Should find and correct the issue I'd think.

John

 

[Shiftless]

You do know that the big box stores have machines that cut and thread pipe for customers, right?
I recently built a large shelf system using 3/4 inch black pipe. H.D. did all the cutting and threading for me. The charge was something really low...IIRC it was 50 cents per cut and thread.

Of course the downside is that you have to figure out ALL of your dimensions ahead of time and allow for the losses when tightening up the fittings. But since you’re not using the pipe for gas or liquids, the fittings don’t need to be super tight,

 

[jproaster]

Just watched some short vids that reflect shared wisdom above...and more.

Since I plan to make bar and table frames for my coffee bar, (the home tv stand is primarily to learn), I think that I'll switch to supply house pipe and fittings.

I'll pick up a supply house 3/4" ****** tomorrow to check the die.

John

Btw- the Rigid pipe tools are old and borrowed from a friend who's father was a plumber many moons back. Wondering if it's a good idea to look into my own. I think the R12 Rigid is recommended for 1" and smaller dies.

 

[manwithtools]

You do know that the big box stores have machines that cut and thread pipe for customers, right?
I recently built a large shelf system using 3/4 inch black pipe. H.D. did all the cutting and threading for me. The charge was something really low...IIRC it was 50 cents per cut and thread.

Of course the downside is that you have to figure out ALL of your dimensions ahead of time and allow for the losses when tightening up the fittings. But since you’re not using the pipe for gas or liquids, the fittings don’t need to be super tight,

Good luck finding someone at the bigbox store who knows how to properly operate a threader....

 

[James-W]

You can usually buy pre-made lengths of pipe already threaded. Not sure you could find exactly the lengths of pipe that you need, but it might be worth looking into.

 

[36truck]

If the couplers you have are Chinese made that could be the issue. Their threads are not very uniform.

 

[jproaster]

Thanks again all. There are so many variables. Gonna get the die tested with a supply house threaded ****** and go from there. I've put my Milwaukee portable band saw in a Swag table to cut the pipe- works great btw. So once the threading is addressed, making custom sized pieces should be no problem.

John

 

[Dumber than lumber]

I remember running one of those ratchet style threaders in the mid-70's. It was really fascinating to see how it worked. The warehouse had one of those big chain strap ridgid pipe vises with the wide ***********.
And then there was that reamer so the insulation wouldn't get shaved off the wires as they were pulled through the pipe.
A few weeks later they got the motorized threader. That made a huge difference when we had to do 6 pieces of 3" pipe on a regular basis.

 

[BD1]

Big box store is all import stuff. You are lucky the threads didn't rip out. Threading by hand will definitely help. Test the caps on a ****** in store. You should get at least 3 and a 1/2
turns by hand putting a fitting on.

 

[gungatim]

believe it or not, I have the HF pipe thread set and it works extremely well. been using it for a good 20 yrs. well worth the $39 it cost. if your rigid's end up needing replaced, at least I can vouch that the HF dies thread match to Chinese pipe and fittings.

 

[mrobins297aaa]

believe it or not, I have the HF pipe thread set and it works extremely well. been using it for a good 20 yrs. well worth the $39 it cost. if your rigid's end up needing replaced, at least I can vouch that the HF dies thread match to Chinese pipe and fittings.

I have the Rigid thread set and always wondered how good the HF set was.

HF also sells that copy of the Rigid power hand threader for maybe $150?........I have the Rigid hand power threader also that I bought in 1990 for over $600, I always wonder how good the harbor freight one is.

edit it's 184.99 at HF, It's a exact copy of the Rigid.

 

[tonyprovo723]

Is electric pipe and plumbing pipe the same thread combinations? If not, that could be your hang up.

I tried looking but did not find a quick answer.

Sent from my SM-G965U using The Garage Journal mobile app

 

[The Cobbler]

threads on electrical conduit are not tapered, they are running threads as far as I know

 

[jproaster]

Checked the die with a supply house 3/4 ****** and all seems well.
So. I put a partially threaded end into the die and used much more oil and backed the die every so often- threads are much better. I'm gonna say that lack of oil was my problem.

Hopefully I'll finish my last four pieces tomorrow.

Thanks for the help guys.
John

*Also some of my problems may be related to what was mentioned above- tapering of the threads. Black pipe threading is tapered. So. I believe one must thread the end completely to get first threads of the pipe to fit into the fittings. If I get this right, the very end of the pipe continues to be altered until it reaches the end...making it smaller.

 

[manwithtools]

threads on electrical conduit are not tapered, they are running threads as far as I know

Rigid conduit has the same thread profile as black iron pipe. The fittings can be straight or tapered depending on application. The reason for being tapered is to be waterproof, kind of the opposite of water pipes intention.

 

[2oolhound]

^^^^ adding to the above Yes there is:

NPT National Pipe Thread which is tapered so the threads bind eventually and seal liquids or air pressure etc.

NPTS National Pipe Thread Straight which is the same pipe thread pitch but they aren't tapered but continuous. NPTS will allow more adjustment to have parallel pipes stay equal lengths but they are less common.

 

[jproaster]

^Good to know.

 

[manwithtools]

^^^^ adding to the above Yes there is:

NPT National Pipe Thread which is tapered so the threads bind eventually and seal liquids or air pressure etc.

NPTS National Pipe Thread Straight which is the same pipe thread pitch but they aren't tapered but continuous. NPTS will allow more adjustment to have parallel pipes stay equal lengths but they are less common.

NPTS - Much less common is correct.

 

[jproaster]

While I'm at it..."how do I seek/understand fittings (or pipe threading!) when it's obvious that twisting that pipe into two opposite end fittings means some threading differences?"

Is the short answer that you thread one end clockwise and the other counter clockwise?

Thanks guys.
John

*Ok. Just watched a video where a guy threads one leg at a time on a simple four legged table. So that's my DUH! moment. However, since I'm hoping to create more complex creations for my coffee bar, I'm foreseeing a need to reverse threads or what have you.

Getting much better at threading btw. Finished threading all my pieces last night for my shelf unit.

 

[acer66]

You do know that the big box stores have machines that cut and thread pipe for customers, right?
I recently built a large shelf system using 3/4 inch black pipe. H.D. did all the cutting and threading for me. The charge was something really low...IIRC it was 50 cents per cut and thread.

Of course the downside is that you have to figure out ALL of your dimensions ahead of time and allow for the losses when tightening up the fittings. But since you’re not using the pipe for gas or liquids, the fittings don’t need to be super tight,

HD here refuses to cut black pipes because of legal reasons
but lowes does it for free.

 

[2oolhound]

While I'm at it..."how do I seek/understand fittings (or pipe threading!) when it's obvious that twisting that pipe into two opposite end fittings means some threading differences?"

Is the short answer that you thread one end clockwise and the other counter clockwise?

Thanks guys.
John

*Ok. Just watched a video where a guy threads one leg at a time on a simple four legged table. So that's my DUH! moment. However, since I'm hoping to create more complex creations for my coffee bar, I'm foreseeing a need to reverse threads or what have you.

Getting much better at threading btw. Finished threading all my pieces last night for my shelf unit.

You're over thinking it. All threads are cut right hand only and they always work that way. All pieces like legs or horizontal runners are parallel to each other with the same threads.

 

[jproaster]

Yeah. I think I'm overthinking it too.

However I did just watch a short Lowes vid about building what they call a "Harvest Table." I noticed they used a pipe union in a cross member assembly.

 

[bimmer1980]

Yes, you will have to really plan your project so that all the fitting can thread together in the right order.

Careful application of unions goes a long ways in allowing for tightening the various threaded ends.....

In your application of furniture, it is less critical.... When trying to do fluid tight fitting for air, gas or water, it is much more critical.

I had a ****** of a time with some of the fittings for my gas line for the garage... liberal application of the pipe dope goes a long ways....

Post some pics of your project when you make some progress!

 

[metlmunchr]

If the OP plans to paint these projects, it would be a big time saver to purchase uncoated pipe from a steel supply house rather than the typical varnish coated stuff from a box store or plumbing supply house. Uncoated pipe has the same appearance as mechanical tubing, but is made to pipe dimensions.

 

[jproaster]

If the OP plans to paint these projects, it would be a big time saver to purchase uncoated pipe from a steel supply house rather than the typical varnish coated stuff from a box store or supply house. Uncoated pipe has the same appearance as mechanical tubing, but is made to pipe dimensions.

Definitely look into this. I do plan to alter the appearance somehow.

Thanks
John

 

[rlitman]

You do know that the big box stores have machines that cut and thread pipe for customers, right?
I recently built a large shelf system using 3/4 inch black pipe. H.D. did all the cutting and threading for me. The charge was something really low...IIRC it was 50 cents per cut and thread...

Around here, the price to use that is outrageous. They charge one price for the stick of pipe, but if you want it cut, they charge you by the foot for each piece you want, and the per foot price is roughly double the price of the whole stick.

 

[gungatim]

If the OP plans to paint these projects, it would be a big time saver to purchase uncoated pipe from a steel supply house rather than the typical varnish coated stuff from a box store or plumbing supply house. Uncoated pipe has the same appearance as mechanical tubing, but is made to pipe dimensions.

I try and find the uncoated pipe but not everyone has it. if it's black and shiny you need to sand it, if not a good wipe with acetone followed by (what I use) cold bluing paste from a gun shop. gives a nice black oxide coating without painting; just wipe it on and off then light oiling. that is what I did in the attached pic of the lamp I made from a call box and old garden light shade. the oil soaks in and dries and isn't "oily" like you'd think (used gun oil but mineral oil is probably the same).

 

[jproaster]

Thanks for the many ideas for my projects. Going to assemble everything over the weekend for fit and then treat the pipe. Hopefully have a pic early-mid next week.

John

 

[493mike]

I was taught between 3 and 4 turns by hand for thread depth (UA trained Steamfitter) to get proper engagement. Most pipe is coated/varnished because customers don't like to pay for rusty material.
Mike