PSI-Something doesn't add up.

[trains are bad]

OK. I was thinking.

I just put a spyder compact vertical adaptor on my fullsize Bob Long millenium.

Pressure is a measure of force per area. Right? Pounds per square inch.

The diameter of a spyder compact vertical adaptor is about .785". That's .393" radius. .393(.393)(3.14)=.485 square inches. At 1000psi of unregulated CO2, the vertical adaptor should have 485 pounds of pressure on it. Here is where you show me my math is wrong.

Spyder compact vertical adaptors are held in a by a little screw. 483lbs is a huge shear load in that screw, and I can't accept that it actually takes that much. So what doesn't add up?

[speedyejl]

Think about this, the threading on burst discs are holding back 4,500psi of preassure. Screws are pretty strong.

Aside from the fact that screws are strong heh, you also have the concept of preassure a little off. A sample of gas pushes outwards on it surroundings, so every part of your Bob Long has the same amount of preassure being exerted on it. Hard to explain but think about compressing a sponge in your hands. It pushes out in all directions, not just one spot.

[trains are bad]

A sample of gas pushes outwards on it surroundings, so every part of your Bob Long has the same amount of preassure being exerted on it. Hard to explain but think about compressing a sponge in your hands. It pushes out in all directions, not just one spot.

I understand that, that is why I calculated the pressure exerted on the vertical adaptor.

Think about this, the threading on burst discs are holding back 4,500psi of preassure. Screws are pretty strong.

Have you seen the stock screws on cheap spyders? Besides being very smal, they look like they cost .000000001cents each. Much smaller and lower quality than burst disks. Also, the loading is completely different.

[CoolHand]

You did the math correctly.

The biggest thing that you are missing here is that the tensile strength of even the crappiest (think Brass Eagle) steel is upwards of 50,000 PSI UTS (Ultimate Tensile Strength - the point it breaks at).

Now for some more math:

#10 machine screw R = 0.095 in, so cross sectional area = 0.02835 in^2

Now 50 ksi * 0.02835 in^2 = 1417.5 lb(force) UTS

Now your 485 lbs of force is exerted on a fastener with a UTS of 1417.5 lbs (at the lowest), which gives a factor of safety of 2.923

If it is loaded in shear, then the USS (Ultimate Shear Strength) is .5 * UTS, giving a factor of safety (once again, at the lowest) of 1.462

Add to all this, the fact that the little screw is probably Stainless Steel, which means you can basically double all those numbers we just derived.

That's more than acceptable, play the game, and worry no more.

[trains are bad]

That's pretty wild. I still have a hard time visualizing it though.

[athomas]

The many parts of our markers do hold back some pretty amazing forces if you think about it.

The output pressure of CO2 at room temperature is about 850psi. If you were to knock the threaded end off a CO2 bottle and expose this force, it would send the bottle off like a rocket. The force would be a concentrated force on an area similar to the one for the ASA vertical adapter. Its pressures and forces like these that require us to use good quality parts and some common sense when handling our markers.