Bad pipe threads

[HVAC HAWK]

what do you think is causing this to happen
the cutters are new
the pipe was cut straight
???????

http://i154.photobucket.com/albums/s279/hawk63/IMG_0905.jpg

http://i154.photobucket.com/albums/s279/hawk63/IMG_0908.jpg

http://i154.photobucket.com/albums/s279/hawk63/IMG_0904.jpg

[leakfree]

A little too aggresive with the reamer ?

[plumb4life]

Were the cutters put in the die in their numbered order? Are you using cutting oil and not some other kind? Also the foreign pipe these days can have hard and soft spots causing galled threads. Try a different piece of pipe for giggles.:)

[Steamfitter638]

Did you ream after threading?

[plumberscrack]

The threads look good but not great. What pipe cutters are you using and are you torquing them down too much?

[drtyhands]

I'm wondering about the order.
The flat tops on the ridge of the thread.
Sometimes when the dies need to be tightened up I'll see something similiar.I've never seen an end like that though.

[drtyhands]

I don't see much of a taper.Or maybe it's me.

[plumberscrack]

Maybe the cutting teeth are out of order in the diehead

I don't see much of a taper either

[HVAC HAWK]

Were the cutters put in the die in their numbered order? Are you using cutting oil and not some other kind? Also the foreign pipe these days can have hard and soft spots causing galled threads. Try a different piece of pipe for giggles.:)

im using oil dies are in the right order and i think it is foreign pipe

A little too aggresive with the reamer ?

nope

Did you ream after threading?

before

The threads look good but not great. What pipe cutters are you using and are you torquing them down too much?

a Ridgid 32895

I'm wondering about the order.
The flat tops on the ridge of the thread.
Sometimes when the dies need to be tightened up I'll see something similiar.I've never seen an end like that though.

i do check this every so often

I don't see much of a taper.Or maybe it's me.

there is a taper just cant see it in the picture
this does not happen this bad all the time but the first thread starts off rough a lot


thanks for all the ideas

[Vince the Plumber]

how many turns of the fitting by hand before it gets tight?

Vince

if i recall correctly, about 2 full turns by hand.

[MoJourneyman]

I was threading 1.5" black iron this week, started with a Reed die, tore out some threads, so I switched the my ridgid die. It was even worse, turns out the teeth were pretty worn out, so I bought a new set. It was identical to the reed die with these new teeth. my conclusion was imported, low quality pipe. I can't think of what else might have done it.

[Chemeng]

It says USA on his pipe, or is that writing part of the pipe "spec"?

[plumb4life]

I have had to use motor oil before in a pinch, and rough, jagged threads were the result. Good, clean cutting oil (like Hercules or Ridgid) makes a big difference. Fittings should thread on 2-1/2 to 3 turns by hand.

[plumb4life]

USA, a city in Japan. (no kidding)

[DELCASE]

Vince is just for the pic
that pipe says USA
Was it all your pipe or just the 1 1/2" ?

[drtyhands]

how many turns of the fitting by hand before it gets tight?

Vince

if i recall correctly, about 2 full turns by hand.

Three lose
Three tight
Three left
Is how I was told so many years ago.
Unfortunately it appears that I only have about two left on a proper joint.

[Vince the Plumber]

Three lose
Three tight
Three left
Is how I was told so many years ago.
Unfortunately it appears that I only have about two left on a proper joint.

maybe your just too darn strong.:D

nurses love plumber's shoulders.

i wrote that down, thanks.

i recall one of the other members mentioning 3,3, and 3.

Vince

[HVAC HAWK]

it goes on the right amount

[MoJourneyman]

Vince is just for the pic
that pipe says USA
Was it all your pipe or just the 1 1/2" ?
I don't know yet honestly, I ran the 1 1/2 trunkline and got called to help out on another project, i'll know about the rest when I get back to that house next week.

[PLUMBER RICK]

don't know charlie:confused:

but didn't you see how i hand threaded the 1'' black at the roundup:D

rick.

[Bob D.]

Seems like the only thing you have not questioned is the dies themselves. Do you have another set you can try, or did you have the same problem before you went to the new die set?

That first thread looks torn, but it could be happening as the pipe exits the die, not necessarily when the first thread begins cutting at the start.

Are these hand cut, machine, or are you using a pony? Can't tell from the photos what the setup is. Looks like a you have a power head with hand dies from the little bit I can see in the one photo.

[drtyhands]

don't know charlie:confused:

but didn't you see how i hand threaded the 1'' black at the roundup:D

rick.

Wow Rick
This is the first I've heard.Please tell me more.

[G3sprinklers]

Looks to me like he is threading with a 300 machine and hand dies with a bull pan oiler.

I have found that with some brand new dies do not cut very well out of the box until they have cut several sets of threads, seems like it burnishes the cutters or removes the burrs from the factory grind.

What kind of cutting oil are you using? and even if it is good quality oil it does wear out. Is there water in your oil?

I use a medium cutting oil that is high in sulfer and it works great on black steel pipe.

I try to get 3 to 3 1/2 turns by hand to set my dies with and two with a wrench to get it tight, should leave 2 to 3 threads showing. With the china fittings this is a real pain because they are not consistant at all.

Good luck

G3

[G3sprinklers]

After looking at your pics again the threads are not sharp on the ends and almost look bent over. I think you have some junk dies, try another set to make sure, or just put the old ones back in. What was the reason for putting in new dies? were they doing the same thing?

G3

[lovetheUSA]

The chart in the link below show # of hand tight turns and # of wrench turns. But they also throw in the caveat that in the field, thread are oftern not threaded as long as the "spec". I have often wondered if the cheap black pipe found everywhere these days...if they "cheat" on the wall thickness!


http://www.sizes.com/materls/pipeThrd.htm

[HVAC HAWK]

i use a 300 machine , new oil , hand dies

Bob i will look next week when i do more threading if it is happening when i put it in reverse to take the die off


and rick no i did not see you do that remember i was not there that day

[stokefire7]

Nicholson pipeliner, 60-30 triangle, little skill they can be salvaged. I've ran into that myself. ( where are they getting their ore from these days?) remember when it was brittle?

[drtyhands]

The chart in the link below show # of hand tight turns and # of wrench turns. But they also throw in the caveat that in the field, thread are oftern not threaded as long as the "spec". I have often wondered if the cheap black pipe found everywhere these days...if they "cheat" on the wall thickness!


http://www.sizes.com/materls/pipeThrd.htm

Maybe wall thickness.But definately Alloys.
I used to be able to put some arm into tightening a 3/4" joint.Now I have to hold back and wait to feel where the pipe is at it's max seat right before it "Mauls"/strips out for an easy bury into the fitting.

[G3sprinklers]

Not sure where they came up with this chart but I would challange it.

1. PIPE is sized by the O.D., hence that is why it is called nominal pipe size and then is called out by its schedule number or wall thickness. If you measured it by the I.D. when the wall thickness changed the I.D. would also change.

2. The chart shows hand tight turns and if you look at the number of threads in their example diagram and what the chart call out, something does not add up. Starting with the two inch you run out of threads by the time you wrench tighten it.

3. The seal does not come from jamming the last threads of the pipe into the first threads of the fitting. Somewhere in the middle they will start to bind or jam to the point of "wedging" together to make a leak tight joint. The addition of pipe "dope" aids in the process of making the joint up, it provides lubrication and some even acts as a shim to take up all of the free space from imperfect threads.

At least that is my take on the situation along with the machinery's handbook.

Been making threads for 22 years and all of our piping is hydrostatic tested at 200 psi for two hours, even our CPVC!

G3

[HVAC HAWK]

i will chock this one up to cheep pipe

[G3sprinklers]

We got some 2 1/2" pipe one time that had flat spots on the outside. Had to take it all back, even the three or four pieces that we had already fabbed up.

G3