Cutting 1/2" BSP Threads

[RWD3M]

Hi all,

I've just ordered up a pile of pipe and fittings to put an airline or two into my shed. I've gone for galvanised steel just because I find it far more aesthetically pleasing!

My question is, is the cutting to length and threading of the pipe an exact science? Anyone have experience of it?

I've found I can rent the kit for about £40/day (outrageous!) but haven't used it before.

Cheers,

Richard.

 

[mike os]

straightforward enough

 

[Mikey D]

Make sure you use cutting oil or paste , for the joints Loctite pipe seal I think it's called is good stuff .

 

[waddycall]

Just cut the thread till the pipe reaches the end of the die. As said use plenty of cutting oil. Aerosol is best. If you’re using a powered threader like a REMs you don’t need a vice. If it’s a manual threader a vice is pretty much essential.
When you’re planning the pipe route bear in mind that you’ll probably need to fit unions in certain places so you can screw it all together. There’s also a limit to how short a length you can thread!
I’d go for galv too.

 

[Mr Fixer]

I’ve only ever used a powered threader made by record. On that you can alter the thread length and the amount of bite on the dies to get a tighter or slacker thread. It’s much a case of trial and error to start with. You should ideally have a couple of threads showing out of the fitting and have a reasonably tight thread. You will probably get away with a few wraps of PTFE tape, but there is a yellow coloured loctite 577 you can get which is very good providing you degrease the parts before use.

 

[Kayos]

Work to a fitting, you can only screw say an elbow on then a pipe in, you can't fit an elbow to 2 fixed pipes

 

[Agroshield]

...When you’re planning the pipe route bear in mind that you’ll probably need to fit unions in certain places so you can screw it all together. There’s also a limit to how short a length you can thread!
I’d go for galv too.

Unions are used more so that sections of pipe can be removed for maintenance, etc. rather than as an aid to assembly. If you find yourself needing a union just to assemble the pipework, you have probably started in the wrong place.

Short, threaded-both-ends pieces of pipe are available from your supplier and are called barrel nipples.

Small galvanised is tricky in a Record-type threader as it is slippery and can spin in the chuck, marring the galv. If you hire a machine, clean the chuck jaws very well before you start, to maximise their grip. You will need a small tin of Galvafroid for touch up on the exposed threads. Think also how you will tighten it as Stilson scars are not the best. Do not grip the end of any fitting without a pipe screwed into it as you can distort the threads. If you need to grip onto an unfilled end, screw a nipple hand tight into it.

Do not tighten everything to three grunts. Go to 1 1/2 on each end as you may need the remaining 1 1/2 to align bends or tees.

You will have to do a test piece to see how much length you need for the threads in the fittings as this can vary (some fittings are looser than others). Cut a piece of a known length and screw it fully into two fittings. Measure between the face of the fittings. Subtract second number from first and divide by two and that is your thread length.

 

[waddycall]

Unions are used more so that sections of pipe can be removed for maintenance, etc. rather than as an aid to assembly. If you find yourself needing a union just to assemble the pipework, you have probably started in the wrong place.

It never hurts to have a few to get you out of a tight spot. It’s rarely a perfect world where I work.

 

[RWD3M]

Guy's,

Terrific advice, thanks.

I shall read this all a few times before I get started!

My plan is fairly straight forward.

A run down one side of the shed incorporating a main filter near the compressor and a couple of regulators, drain valves, oh and a Tee (blanked off) in case I decide later to run some more over to the other side.

I've tried to upload a pdf but not sure if it has worked.

Edit: Ah, looks like it did work

 

[Shox Dr]

I would use Rocol Oilseal, with industrial tooth floss


Far from cheap but I’ve yet to have it fail. From airline to the exhaust manifold on my truck.

just remember its a total PITA to fix leaks after its all in.

 

[RWD3M]

just remember its a total PITA to fix leaks after its all in.

Yeah, absolutely!

Cheers.

 

[RWD3M]

Just an aside, but it's arrived already!

How does that happen? I genuinely ordered it just before I started this thread yesterday and the FedEx man has just dropped everything off, from Glasgow!

 

[Shox Dr]

Yeah, absolutely!

Cheers.

A Co I sub’d to had it, there were so many little leaks a Midsize hydrovane could just keep on top of them. The result was tools wouldn't run as they were starved of air. They all add up.

gaffer came in one day, wanted someone to go round and weld them all up. Tried explaining; wouldn't have it. It leak more, ended up ripping it out

 

[RWD3M]

A Co I sub’d to had it, there were so many little leaks a Midsize hydrovane could just keep on top of them. The result was tools wouldn't run as they were starved of air. They all add up.

gaffer came in one day, wanted someone to go round and weld them all up. Tried explaining; wouldn't have it. It leak more, ended up ripping it out

 

[Shox Dr]

EHP Job

Every Hours Paid

 

[RWD3M]

EHP Job

Every Hours Paid

 

[Mikes]

RWD3M, Are the red marks on your layout pipe brackets? If so, far too close for galvanised pipe. Also, good practice to take the outlet tee facing upward so that moisture drops back into the main which should be installed with a slight fall back to a drain point which can be manual or automatic. If you haven't got your pipe threading gear, for speed, I would use a set of hand held power dies (REMS Amigo or similar) and a good pipe vice. It's very difficult to fit the pipe and fittings without marking the galvanised. just carefully file the marks and apply a little Galvafroid.
For thread lengths for different pipe sizes, look at the GF or crane websites. In Crane, referred to as the 'A' dimension.

 

[Ruffian]

Buy a rotastock and never look back.
Can then thread up to 2" bsp.

 

[RWD3M]

RWD3M, Are the red marks on your layout pipe brackets? If so, far too close for galvanised pipe. Also, good practice to take the outlet tee facing upward so that moisture drops back into the main which should be installed with a slight fall back to a drain point which can be manual or automatic. If you haven't got your pipe threading gear, for speed, I would use a set of hand held power dies (REMS Amigo or similar) and a good pipe vice. It's very difficult to fit the pipe and fittings without marking the galvanised. just carefully file the marks and apply a little Galvafroid.
For thread lengths for different pipe sizes, look at the GF or crane websites. In Crane, referred to as the 'A' dimension.

Hi Mike,

The red marks are indeed proposed clamps. I think I have them at 600 spacing (that lines up with the timbers in the walls!). What do you reccommend?

On the outlet Tee's do you mean the outlets to the regulators? If so, good tip, I like that also from a practical perspective. I won't have to bend down so far to connect a hose!

Each of the regulators has a manual drain and the filter adjacent to the compressor has an automatic one. I can incorporate a fall towards the end of the run, say 100mm over the full length (circa 15m)? which will have a manual drain valve at the end.

I've revised my drawings accordingly. Does this look better or have I missed something?

I haven't got the tooling yet but I'll be looking around fairly soon. I should only have maybe half a dozen ends to thread and am getting lots of good advice here.

Cheers,

Richard.

 

[Agroshield]

Over-bracketing will not hurt, just potentially cost you money. 1200 spacing is probably OK but if it turns out not to be, how much will the postage be for additional brackets? Anywhere you will be pulling on it (outlets), an additional bracket will not go amiss.

The brackets set the stand off from the wall so when going between two fixed walls, you bracket dummy pieces of pipe with elbows on the two return elevations and then measure your actual between face length. What I am saying, I guess, is not to work solely off drawing dimensions but measure the last piece before you cut it. It is better to cut it longer as you can trim 5mm off with a grinder and then re-engage the dies on the thread and lengthen the thread than it is to be short as then you have to throw the piece away or use it elsewhere.

You might know this one way or the other, but I think you need a flexible connection between compressor and line so vibration is not transferred and there is no stress leading to pipe failure.

You can check the length of the pipe when it comes (I think it is 3.6m) so you could slightly revise your dimensions on the long wall to suit full lengths as that saves on threading.