Cutting BSP fitting to size?

[AnimatedGIF]

I bought a 1/2 bsp to 3/8 push fit to go on an lpg regulator which is to be used as a secondary regulator to supply CO2 to my keg for connection to beer engine. The 1/2 inch bsp doesn't go all the way in, though by eye the female thread on the regulator is much deeper, so I expected it would. Is it ok to cut down the thread on the John Guest fitting?

 

[thegrantickle]

I personally wouldnt, I'd replace the o ring with a thicker one or thick gasket.

 

[LeeH]

It doesn’t have too, as long as it’s sealed. Use tape or some kind of gas rated liquid thread sealant.

 

[AnimatedGIF]

I personally wouldnt, I'd replace the o ring with a thicker one or thick gasket.

I hadn't thought of doing that. Is there any particular material I should be looking for in a thicker o ring??

It doesn’t have too, as long as it’s sealed. Use tape or some kind of gas rated liquid thread sealant.

Thanks. Would PTFE tape be ok fo this?

 

[LeeH]

Yes.

 

[Buffers brewery]

I’m guessing one of the threads is 1/2”BSPT (tapered) (regulator?) and the other is 1/2” BSPP (parallel) (John Guest?) hence the gap. PTFE tape should fix.

 

[AnimatedGIF]

Thanks @Buffers brewery - I didn't realise there was such a thing as parallel and tapered. Good to know!

 

[peebee]

Thanks @Buffers brewery - I didn't realise there was such a thing as parallel and tapered. Good to know!

That fitting has an O-ring, therefore most certainly is a parallel thread. Tapered threads seal anyway, although I'll still put on some PTFE tape to make sure (all UK BSP female threads are parallel, only very occasionally you can get tapered female but they will probably have a "Rc" designation).

I stopped using JG fittings, one of the reasons being; put PTFE tape on will created a seal, but also encourages a bit more tightening, at which point the JG fitting easily shears off!


[EDIT: BTW, I think that's a 1/4"BSP thread; the other side - output - is 3/8"BSP.]

 

[Buffers brewery]

I tried to decipher the markings on your regulator and came up with Nova Comet BP 1813 . Found this online which might give a clue to your fittings conundrum…..

EDIT: That’s a rubbish screenshot! You can find info on

http://kazeco.kz/wp-content/uploads/2015/11/NOVALPG.pdf

 

[peebee]

Thanks @Buffers brewery , but the "conundrum" was only caused by the OP only showing half the regulator so I was judging 1/4" by eye alone. I'm rather familiar with those regulators 'cos I recommend them for "cask conditioning" style beers ("Cleese" are the makers).

You can get them without those bits and bobs screwed into the ports like the above picture (horrible POL adapters for one) because removing them can be really tough. You can get the 20-300mbar variants in this country but you have to look hard. The 50-150mbar commonly available variant is all you need for cask emulation.

For anyone wondering, 1000mbar is 14.7 PSI (PSIG to be properly correct), so 50mbar is not very much. Hence you must use LPG regulators as secondary regulators, commonly available secondary regulators will not come anywhere near close and precision low-pressure regulators cost a small fortune.

 

[AnimatedGIF]

Thank you both. I should have provided more info.

[EDIT: BTW, I think that's a 1/4"BSP thread; the other side - output - is 3/8"BSP.]

Yes, that's correct. I have the 50-150mbar as I found a link to it (likely by you @peebee ?) in a thread on using a beer engine, which I found very informative (thanks!).
This is the reg:

50-150 mbar Clesse Propane Gas Regulator - Brooder

BP1813 Propane regulators have variable outlet pressures and are mainly used as single bottle regulators or as a second stage to a High Pressure Changeover Valve. Ideal for use in agricultural applications such as game and poultry rearing, plus industrial or craft such as air heaters. This...

www.gasproducts.co.uk

These are the JG:

John Guest 3/8″ to 1/4″ BSP PI011212S - The Malt Miller

John Guest 3/8" to 1/4" BSP PI011212S Replacement John Guest fitting of our Premium Regulators

www.themaltmiller.co.uk

John Guest 3/8 push fit to 3/8 BSP Adapter PI011213S

This very handy adapter screws into the dump valve on the Grainfather Conical Fermenter allowing oxygen free transfer to keg with 3/8 beer line Features • Push-fit technology • Quick disconnection without the need for tools • Food Quality and suitable for potable liquids • Suitable for soft...

www.themaltmiller.co.uk

 

[Buffers brewery]

According to the chart I found the inlet thread is specified as FEM-Rp1/4 which is female 1/4” BSPT, and the outlet thread is FEM-Rp3/8 which is female 3/8” BSPT, I think

These fittings might be an alternative to plastic…

Imperial Push Fit Stud & Female Push Fittings,For Air ride Suspension Systems | eBay

Imperial Push Fit Stud & Female Push Fittings. BSP Threads with Imperial Bore Fittings. high quality Fittings. For Air ride Suspension Systems. BSP THREAD DATA. Thread Size. Ideal fitting for any application especially pneumatic but can be used with water etc.

www.ebay.co.uk

 

[peebee]

According to the chart I found the inlet thread is specified as FEM-Rp1/4 which is female 1/4” BSPT, and the outlet thread is FEM-Rp3/8 which is female 3/8” BSPT, I think

Rp = R = "parallel". Rc = tapered. Flippin' mumbo-jumbo, it's far easier not looking too closely!

 

[Buffers brewery]

Rp = R = "parallel". Rc = tapered. Flippin' mumbo-jumbo, it's far easier not looking too closely!

I stand corrected didn’t read the table properly. Ignore my post above with tapered fittings although they do parallel ones as well. Think I’ve finished now

 

[AnimatedGIF]

Thanks everyone. I'll crack out the PTFE tape rather than the hacksaw and see how it goes.

 

[peebee]

Thanks everyone. I'll crack out the PTFE tape rather than the hacksaw and see how it goes.

Remember what I said about over-tightening (and if they do shear, you might say "but I didn't over-tighten" - I'll believe you!).

If it does shear, @Buffers brewery posted a link above to some metal adapters (1/4" out-of-stock at this moment). From my favoured supplier too (Context Pneumatics) but their catalogue is devoid of "Kelm" stuff at the moment because of some daft issue further down the line (but they still have the stock if you ask). The metal adapters still use "push fit" whereas I prefer something more secure (and all sorts of other alternatives which can create cerebral aneurisms if you dig about too deep).

[EDIT: BTW, tapered male fittings will be fine into the parallel threaded regulator, they will just tighten before screwing all the way in - that's what creates a seal.]

 

[peebee]

Rp = R = "parallel". Rc = tapered. Flippin' mumbo-jumbo, it's far easier not looking too closely!

@Buffers brewery : Told you it was "mumbo-jumbo"! "Rp = G..." not "R". My slipup, "R" covers tapers, but Rp means "cylindrical" or parallel if you prefer. "Rs" is apparently external tapered or BSPT as opposed to internal thread (Rc). Gawd knows what the "c" in Rc stands for. I've seen some suggestion that tapered and parallel have different pitch, but not that I've experienced.

Had enough? I have

 

[AnimatedGIF]

I won't overtighten, I promise.