oxygen tank death

[TrimixToo]

Yup. ^^^

If I recall correctly, it's *x* turns past hand tight. I don't recall the value of *x*, and I am not looking it up tonight, but suffice it to say that I get out a Large Posterior Wrench(tm) when I need to valve or devalve a T bottle. I strap the tank to a trailer hitch on my SUV or motorhome because nothing else I have will hold it securely enough to prevent it from rotating unless I use a tree.

I entirely agree that nobody human will loosen one by hand, even if the tank is not pressurized.

To go off on a tangent, when you're done tightening the valve (and nursing the resulting hernia and rotator cuff tear), there is a specification for the minimum number of exposed threads on the valve. If it falls below the minimum, you order a valve with threads that are bit larger in diameter. I don't recall how many oversize valves are available, but they are used to compensate for tank thread wear.

Per Sherwood, *x* is three full turns for tapered valves installed in steel cylinders. The minimum number of exposed full threads after tightening is two. Also, there is a maximum number of exposed threads, which is five. I suppose the latter is to make sure you don't put an oversize valve into an unworn tank having nominal thread dimensions.

 

[happy-diver]

No caps over here

And how do you paint the 105kg mutha

 

[Dan]

Using a cheater bar is a no no at my work. Get the right tool for the job.

 

[happy-diver]

you mean the smart stick

the how best not to do anything work place

 

[Wookie]

Using a cheater bar is a no no at my work. Get the right tool for the job.

I'm more appalled at the adjustable wrench, but not everyone can have every wrench size.

 

[PBcatfish]

Per Sherwood, *x* is three full turns for tapered valves installed in steel cylinders. The minimum number of exposed full threads after tightening is two. Also, there is a maximum number of exposed threads, which is five. I suppose the latter is to make sure you don't put an oversize valve into an unworn tank having nominal thread dimensions.

This brings up a good point. Pitch diameter tolerances on threads can sometimes be off a bit. I see this on tapered threads, like NPT pipe threads, more than I see it on straight threads. It seems to be the worst on lower priced import parts. The check on the number of exposed threads is a check against the pitch diameters of the two parts being too far apart or too close.

If this incident happened in India, then I would expect an Indian made valve would likely have been used. Perhaps the valve had a quality issue. Or perhaps the threads in the neck of the tank were not tapped deep enough or were tapped too deep, causing a small number of threads to be engaged.

 

[PBcatfish]

I'm more appalled at the adjustable wrench, but not everyone can have every wrench size.

I'm curious why you think an adjustable wrench is a poor choice here. When grabbing a valve with a wrench, you often need a very deep throat on the wrench to get full engagement on the flanks of the valve. a large adjustable gives you this option, where a standard open end wrench does not. In my shop, I have standard wrenches from 1/4" up to 2-1/8", but I still reach for a large adjustable when working with tank valves.

 

[PBcatfish]

No caps over here...

None of the Auzzy tanks have caps??? I didn't know that.

 

[Wookie]

I'm curious why you think an adjustable wrench is a poor choice here. When grabbing a valve with a wrench, you often need a very deep throat on the wrench to get full engagement on the flanks of the valve. a large adjustable gives you this option, where a standard open end wrench does not. In my shop, I have standard wrenches from 1/4" up to 2-1/8", but I still reach for a large adjustable when working with tank valves.

I came from nuclear power. Adjustable wrenches were forbidden (which means we had to keep them hidden). Look at any scuba shop for the cylinders with rounded valve flats to know the reason.

I will typically make a tool to remove a valve or other threaded fastener rather than rely on an adjustable.

 

[PBcatfish]

I came from nuclear power. Adjustable wrenches were forbidden (which means we had to keep them hidden). Look at any scuba shop for the cylinders with rounded valve flats to know the reason.

I will typically make a tool to remove a valve or other threaded fastener rather than rely on an adjustable.

I'm familiar with the standards in the nuc industry. I can understand your perspective based on that background.

While I agree that making a custom tool to fit a specific valve would be the best possible option, I have found that a large enough, good quality adjustable, that has been properly tightened, will provide good results on valves in most cases. I am more apt to reach for a large adjustable first, but if the valve did not want to play ball with me, I would not be opposed to then firing up the Bridgeport & milling a custom tool to get the job done, rather than rounding out the flanks of the valve.

One interesting side note, I recently learned of a shop in Europe that removes DIN valves by screwing a tool into the DIN fitting, rather than using a wrench. My local dive shop still just uses a big adjustable. I had considered firing up my Clausing Colchester & cutting the DIN threads into a piece of bar stock, so that I could have a tool like the shop in Europe, but I have concerns about the O-ring seating face getting damaged under stress caused by that kind of tool. I'm still kicking that idea around in the back of my head.