Thread size on the AF fitting
What is the thread called on the Air force bottle fitting to SCUBA fitting ? IT is the one with the O-ring female bottle fitting thread on one side and the small male thread on the other end, with metal washer. Fits onto the SCUBA adapter from Air force .
Thanks
Later
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Yes, they are commonly called ‘Dowdy seals’ or Dowdy washers sometimes. Check with HPA and Hydrolic fitting shops.
In an emergency I’ve used an o-ring inside a flat washer. The washer has to be a little thinner (about 10%) than the ring and needs to be a pretty tight fit on the OD of the ring. I’m not proud of this kluge, but I’ve done it and seen it done.
The metal ring keeps the soft seal from ‘blowing out’.
HPA is not to be messed with, best to find the rignt part.
Doug Owen
By the way, is the silver ring from the pic available for sell? My clamp didn’t came with it and I can’t use it!
😡
Later
Yup, I think I agree. I think I just said the pitch in metric was 1.337mm (19 to the inch)…..yup, that’s what I found at the source quoted above……
Fer sure not metric, nor is it normal pipe threads.
Doug Owen
Well it’s not a 1.5 thread pitch, nor 1.25. I don’t believe it is metric. The 1.25 is close, but not right on.
Later
Why would it be metric? Nothing else on the gun is, it’s made in Texas, not really a bastion of such stuff.
It is the already widely used BSP standard (sometimes listed a ‘G’ or BSPP). Brit stuff, from long before metric became the rage. While 14 X 1.5 mm is close, the actual metirc measures are 13.157 for the dia and 1.337 thread pitch (19 to the inch, a fairly close match to Yankee 20 TPI):
http://en.wikipedia.org/wiki/ISO_228
Doug Owen
That was what I needed – 14m x 1.5 Excellent.
Here is the fitting. I know you’ve seen them.
thanks
later
The threads on the AF adapters are metric. On the 1/4″ the thread size is 14mm X 1.5 mm. That is the Tap size to cut the threads.
1/2″ physical diameter is 1/4 bsp (straight pipe) thread. sounds wierd but pipe thread sizes are based on the i.d. of the tube/pipe therefore the threads are much larger than their designated measurement.
This one is 1/2″ on the OD of the threaded male side.
Later
thread on the bottle adapter available in 2 sizes, 1/8bsp and 1/4bsp on the male end that threads into the scuba yolk or onto the handpump.
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Thank you for your answer! I’ve ordered it from Airforce (and they said they will send it to me in Brazil!!!).
But I’ll look for Dowdy seal on a shop, thanks for the name!
Darn, I thought I WAS smart, hahahahaha…
Bought a couple of washers this morning and was going to do just what you described. My washers are a bit too thick, I’ll sand and polish it…
Thank you!