Voit SPG with compression fitting rather than swivel O-ring

[Greg Barlow]

I was pleased to win an eBayed Voit SPG for a mere ten dollars, but was disappointed to find that it uses the older compression fitting hose rather than the modern swivel with an O-ring. The hose that came with the unit had the outer rubber cover removed by a previous owner.

Does anyone have an idea if HP hoses for such a ftting are available? I am wondering if I shouldn't just use the gauge for display, as it is also lacking a pressure release plug. A rupture of the pressurized metal tube would result in an interesting event. It was rather surprising that the gauge was of the older style, particularly cosidering that it is marked in both PSI and BAR.

Other than the fitting, it is in great cosmetic shape.

Thanks.

Greg

[crimediver]

Greg,
A couple of years ago I purchased a HP hose that had the female end tapered to accommodate a compression fitting and also could be used with a HP spool/ o-ring. I suspect that they are still available. I remember I purchased the hose on a trip to FLA but don't know exactly where-St. Petersburg possibly. I wish I could advise you better. I later used this hose to make an equalizer type fill whip. Since this was in the recent past I suspect they are still being made.

[luis]

I believe that the standard Scuba HP hose is actually a SAE 37 degree flared compression fitting (a.k.a. JIC fitting). Inside the swivel nut on every HP hose I have seen the fixed portion is a female cone to accept the male fitting.

The use of the O-ring spool is just an adaptation by the Scuba industry. Some new hoses may have done away with the female cone shape, but I don’t think I have seen any like that.

You can also notice that the swivel nut is also kind of loose even with a pressure gauge and O-ring spool in place. Again (if I am correct) this is because that fitting was originally design to tighten against a compression fitting, not to have a relatively loose O-ring spool.

[Greg Barlow]

Luis,

The fitting size on the gauge is consdierably smaller than the current HP hoses that are used on modern regs. I wonder if there is a compression fitting adapter that could be used?

Greg

[luis]

I would think so. If you have a good hydraulic fitting supplier locally, it may be easy to at least identify the fitting. They may only have it in steel, but they may be able to order it in SS or brass for you. Brass would be easier to seal.

The hard thing may be identifying the correct fitting without actually being able to mate it on the spot.

Here is a link to the fitting I thin you could use:
http://www.midlandindustrial.com/index. ... o&page=284

Look at the bottom right of the page.

[Greg Barlow]

Thanks for the information, Luis. A friend of mine who works on aircraft put a male aluminum hydraulic connector into the original hose fitting. He said that it is a #3, but he is not certain as to what that would correspond to in the compressed gas thread size. He said that aircraft hydraulic fittings are given a number for designating size.

I will take your advice, and go to a store that deals in compression fittings. I would prefer brass, as it would likely require less torque to create a proper seal.

Greg

[Nemrod]

If you used an AN fitting in aluminum then it should also be available in stainless. If you give me the MS/AN number I can probably obtain one.

James