Thread cutting 3/4" galvanised tube

[Fredxx]

3/4" BSP actually has a larger OD than 25mm.

[polygonum_on_google]

Yep - 26.9 mm.

[polygonum_on_google]

I rather assumed that it would be! But as I have never cut 1/2" either, wasn't sure where either lies on the "tough to cut" scale.

[polygonum_on_google]

I have the flanges I plan to screw the pipe ends into. That was the easy bit!

I want rigidity and low flexibility. Am trying to make some tools! Will post piccies eventually.

[Dave Plowman (News)]

I'd say you could buy a cheap welder capable of doing steel tube for less than the cost of the vice and dies?

[harry]

Yebbut ruins the galvanising.

[polygonum_on_google]

Maybe! And an interesting approach but it would not work for me as I need to be able to disassemble parts. Sure, it could do some bits, but not all. By the time you add a welding mask, rods, and time and effort learning how to weld (and waste from so doing), maybe not.

[polygonum_on_google]

Wouldn't be the end of the world - I could even use ungalvanised tube - but thought starting out with some zinc would help reduce the likelihood of rusting over the years.

[Cynic]

I had both pipe vice on stand which formed part of a conduit bending kit and a set of manual 1/2" to 2" pipe thread stocks & dies which I used prior to retirement. I don't know where you are but what you're proposing is pretty trivial in the scheme of pipefitting. A word of caution- trying to grip round steel pipe in a normal vice tight enough to cut a thread will result in crushing it out of shape. I'd suggest cutting your lengths ready to save time then hire kit over a weekend to cut the threads. Are HSS still around in your neck of the woods?

[polygonum_on_google]

Thank you. Yes - we have HSS but another company offers a pipe threader at a more sensible £20 a day (rather than £87). Need to check with them tomorrow if there are any extra charges for the cutters.

Is there anything special about the cutting lubricant? Or would I get away with ordinary lubricants?

[spuorgelgoog]

The HSS is an *electric* pipe threader.

HSS manual pipe threaders are about £40 a day.

I assume the £20 a day is for a manual threader? But if that is sufficient then it is a far more sensible price!

Owain

[Brian Gaff (Sofa)]

If its galvanised, though surely the act of cutting removes this, and if you want to remove it, it might rust up. Brian

[charles]

It's about 10 years since I did any thread cutting, but I think I used a pot of tallow. You could just ram it over the end of the conduit.

[tony sayer]

Galvafroid paint?...

[charles]

Following up my own post, I see that TLC call it "cutting compound". They wouls also sell you all the tools. A complete set for 20 & 25mm is £36 + vat

[charles]

so does putting a thread on it or cutting to length.

[polygonum_on_google]

Yes, true, but slapping a bit of suitable grease on should protect it where the threads mesh. And I'll probably end up painting the rest eventually. (Yes, I know the issues of painting zinc.)

[polygonum_on_google]

No - it is electric.

One of these:

(Might be a slightly higher or lower spec. or an older model but looked like this and is this make.)

[polygonum_on_google]

The usual issues - ends up nearer £50 with delivery and the cutting compound.

[Dave Plowman (News)]

Welding thick stuff like tube pretty easy. And many cheap welders from Lidl etc give you everything you need.

Have you price up the dies etc needed? The ones I bought years ago for conduit weren't cheap then. But of course may be now.