Threading 1 Inch Diameter Steel Pipe What Have I done Wrong?

[pollys1dad]

Hi all,
Back refering to my post, " Thread Steel Pipe To Make Woodworking Pipe Clamps. " Nov 20th 2015.
The other day I was having a go at threading a 1 inch diameter steel pipe with 3 mm thick walls, using a 3/4" BSP die. I used the Draper pipe vice, bracing the end of the pipe on a door while I used my left hand to apply pressure to the die head. I backed off every few turns to release the swarf and squirted some more sulpher based cutting oil on the chasers. I was feeling quite pleased as to how it was going. I then thought I had reached 4 CM of thread and was shocked to see the pipe end, quite badly distorted out of shape.See attached photo. What didn't I do or what have I done wrong? The die head is almost unused, and the chasers are all in perfect condition.
Cheers.
Peter.

[John Evans]

Chinese chewing gum steel? Try turning up a filler plug to support the ID while threading.

[whateg0]

I could be wrong, but 3 mm seems pretty thin to try threading with most of the dies I've used. If I had to do that, I think I would try to use some sort of backer. If that's a tapered die, I could see it collapsing the end of the pipe as you go deeper, too.

Dave

[pollys1dad]

Chinese chewing gum steel? Try turning up a filler plug to support the ID while threading.

Has on pipe Tata Steel Made In UK. I will ask my mate with a lathe about turning up a filler plug,
Thanks.

I could be wrong, but 3 mm seems pretty thin to try threading with most of the dies I've used. If I had to do that, I think I would try to use some sort of backer. If that's a tapered die, I could see it collapsing the end of the pipe as you go deeper, too.

Dave

I've had two Draper die sets including heads and ratchets. The ratchet on the first set became faulty. I did cut some threads quite well on the pipe before with a die head from the first set. I didn't have the pipe collapsing distorting. I still have the die heads from the 1st set, I'll check if is the same as the head I'm using I'll let the forum know.
Cheers.

[Rich_Carlstedt]

That's not pipe, it's tubing mate
Rich

[pollys1dad]

That's not pipe, it's tubing mate
Rich

Yes, sorry my mistake

[warmstrong1955]

Tubing? I don't think so.

3/4" schedule 40 pipe is 1.05" OD, and has a nominal wall thickness of .113"....so 3mm wall.....normal. What's the OD?

I would suspect a problem die alignment, or sharpness, more than any problem with the pipe.

What does your die look like? Is it a regular pipe die, with a OD guide on it, or just a simple one like a bolt threading die?
Is it adjustable?

Bill

[Russ Hanscom]

The threads are a bit ugly looking; not sure whether that is because of the tubing being distorted or not sharp chasers or picture quality.

I have cut a lot of 3/4" pipe threads and never had a problem that looked like your results. If the pipe you have matches the dimensions for 3/4" pipe, then I would look to die issues. If they are adjustable, make sure they are not too tight, sharp, and look at alignment. If you have had the chasers out of the head, make sure they are back in the correct numbered slots - I admit to having gotten the chasers in the wrong slots more than once myself.

[spro]

As said, the walls are deforming. Look pretty thin too. For whatever reason (dull leading edges) I had deformation like that. So being lazy and quite po ed, I cut the pipe and drove in a small section of hardwood broom handle. The pipe acted as a swage so the wood was compressed. After threading, the wood easily drilled out.

[hammermill]

i would check that all die cutters are in proper sequence 1 2 3 4 not 4 2 1 4. they try a differient piece.

[SteveM]

If it's a tapered thread, the die may be crushing the pipe as it gets to the end of the die.

Maybe turning the end down a bit to roughly follow the taper of pipe threads would help.

Steve

[earlgo]

I used to work for Teledyne-Oster a company that made pipe threaders in competition with Ridgid Tools. In the 4 years there I never saw a thread that looked that 'form challenged' or a pipe end that was so mis-shapen. The threads themselves are not clear, but there appears to be considerable tearing on the cut surfaces. So one can conclude, as others have, that the steel is very poor or that the dies are dull or incorrectly made, or in the wrong order in the head, if that is possible. Looked up the Draper ratchet set on Amazon and the 1" die head has 8 segments cut into a single round die. How this left the three lobed pipe end is another discussion.
I am voting for terrible metal in the pipe.
If the pipe says Tata Steel, then it came from a steel plant controlled by the India headquarters in Jamshedpur. It may not be the finest quality available.

--earlgo