Re: [ST] female quick disconnect failure (revisit)

[Dan Wetherington <dnlwthrn@xxxxxxxxx>]

Frederic NIZERY wrote:
> Hi Mike
>
> Thanks for the reply.
> Comments inside.
>
>   
>>> After further digging: mcmaster.com part number 5478K51 is the NPT
>>> version with shut off. They have them in stock, and are easy to buy from
>>> with a credit card. 
>>>       
> Triumph fitting is PSPT and the thread is different.
>
>   
>>> I'm not familiar with the specifics of the installation. What does this
>>> fitting screw into? 
>>>       
>
> Into the metal plate the olds the fuel pump and the fuel filter on the tank.
>
>   
>>> You might be able to use the NPT thread as a direct interchange if the
>>> part being screwed into is fairly thick walled polyethylene. If in
>>> doubt, a quick and careful chase with a 1/4" NPT tap (Make sure you
>>> collect ALL of the shavings!) will modify the hole to accept the
>>> fitting. 
>>>       
>
> I just have normal cylindrical iso taps.
>
>   
>>> The problem with this part is that the
>>> N(ational)P(ipe)T(apered) thread form specifies a (if memory serves)
>>> 3/4" per foot taper of the major diameter of the thread while the
>>> B(ritish)S(traight)P(ipe) thread form is as the name implies, not
>>> tapered. 
>>>       
>
> NPT is 18 thread step per inch while BSPT is 19 for 1/4 fitting. They are both conical.
>
>   
>>> Depending on the "fit" or "class" of the female thread, the material of
>>> the female threaded part, and sometimes the phase of the moon, the NPT
>>> male thread will work just fine. If the female threaded part is made of
>>> a brittle material like nylon or PVC there is a danger of cracking the
>>> part when the brass NPT fitting is screwed in. Problems can also crop up
>>> if the female part is metal; the NPT part might not screw in far enough
>>> to make room for the other half of the coupler, and its attached hose
>>> (tube). 
>>> Sorry guys, slow Monday morning for a change....
>>> My latent fastenerd is showing through.
>>>       
>
> In addition the coupling must have apparently viton o-ring and not buna-n for non leaded fuel.
>
> I found also 
> http://photos1.blogger.com/blogger/7060/1458/1600/Omega%20Fuel%20Fittings2.0.jpg
> which is comming from 
> http://www.omega.com/pdf/tubing/couplings/ft-lcseries/ft-lcseries.asp
>
> And apparently the omega matching ref is FT-LCD100-04BS while colder is LCD10004BPST 
> Viton o-ring should be specified.
>
> I contacted a guy at quickcoupling.net
> He said that would be a 5+5 days shipping. That is 10 days to France.
> I am waiting for the reply from Omega.
>
> Omega has an online store in UK but as they show a 1 week delay while the US site shows "in stock",
> I figured out they forward the order to US.
>   
Fred, in dealing with Omega quite frequently here at work (mostly 
temperature and pressure stuff), I've found they're REALLY good at 
taking somebody's product and throwing a new label on it to sell as 
their own with a markup.  Just an FYI.  I haven't looked at pricing for 
the fittings, so I don't know if that's an issue for them.  They're 
probably Colder (or some other manu.'s) fittings.

Dan
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