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[Geswearf]

I've got a brand new tire valve that I want to thread into the bottom of a spent 100ml CO2 cylinder. If you look at the link, that brass nut screws down on the threaded shank of the valve compressing the rubber gasket against the wheel rim of a car or truck. In order to drill and tap the cylinder I need to know the drill and tap size, but I cannot find anything on common bolt charts. Once I have the information, I'll cut off the head of the valve, drill and tap the cylinder, and then screw the valve into the cylinder and lock it in w/ thread sealant and the nut.

The threaded portion of the shank has an o.d. of 0.403", my calipers 'knife edge' is blunt and I am pretty sure both do not reach down to the bottom of the thread. This 'root' diameter is approximately 0.386" and there are 28 tpi. This tire valve is a standard TP500 type.

Can anyone ID this and tell me what drill and tap size to use?

My motorcycle air bag vest uses these 100ml canisters of CO2 to inflate the vest (Helite Turtle 2) when the lanyard attached to the bike is pulled out of the triggering socket. A heavy spring fires a pointed rod into the cartridge puncturing the seal and allowing the gas to flow into the air bag bladder, deploying the vest. The manufacturer is somewhat vague about how to adjust the vest so that it is not too tight or too loose when inflated. My idea (not very original, I'm afraid) is to put an air valve on a depleted cylinder, screw it into the trigger mechanism of the vest, and use a bicycle pump to inflate the bladder. At this point, everybody who owns a vest in the club to which I belong can adjust the straps so that the vest is secure but not eyeball popping tight.

 

[Flyinfool]

Based on your dimensions it looks like it might be a 7/16-28UNEF thread. The Major Dia is a bit small but this is the closest standard thread in either SAE or metric. Tap drill would be 13/32 (.406) Dia. I never put it past a manufacturer to use a non standard thread.

 

[Alcap]

Im not exactly following what you’re trying to do but if your drilling and taping the cylinder would a 1/8” pipe thread work in place of the valve stem type ? https://www.amazon.com/Breezliy-Ant...8-4-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[Geswearf]

Im not exactly following what you’re trying to do but if your drilling and taping the cylinder would a 1/8” pipe thread work in place of the valve stem type ? https://www.amazon.com/Breezliy-Anti-Corrosion-Schrader-Standard-Compressor/dp/B0B42DW248/ref=sr_1_4_sspa?hvadid=409943633724&hvdev=c&hvlocphy=9006931&hvnetw=g&hvqmt=e&hvrand=7482434136465100370&hvtargid=kwd-285144034009&hydadcr=24657_11410751&keywords=1/8+schrader+valve&qid=1704415378&sr=8-4-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

I want a way to pressurize the vest. With an auto tire/wheel's valve stem sticking out of the bottom of the CO2 cylinder, I can screw the cylinder into the vest's mounting. My bicycle pump will clamp onto the stem and I can inflate the vest. Unclip the pump and the vest owner can try it on and adjust the straps so that it fits snugly when inflated. The vest loses air pressure over the course of a few minutes and will self deflate, but if we work quickly, each vest owner can inflate and adjust his vest. I deployed mine when I stopped the bike on a cambered street near the curb. I did not realize how far away the pavement was on my right side and when I put my foot down there was nothing there. Tipover time and air bag deployment. I was trapped in an enormous vest hug and could barely breathe. I unclipped the vest and unscrewed the cylinder to deflate the vest quickly. But it had been adjusted much too tightly. With this air valve I can remedy that for other folks.

 

[tq60]

I have seen similar to the Amazon link, they work well for adding air to things, use a standard tap.

Stupid questions.

This air bag device, is it something that deploys as an injury reducing device during loss of control?

If yes, do NOT do anything for anybody else, these devices are likely certified and modification voids that, and if used ad things go wrong, even if not related to this, things go south fast.

A lesser risk would be to loom for a service port or other existing fitting that can have a t added.

The co2 tank either has very high pressure or liquid , or liquid co2, either of these result in a great volume of energy or usable air to do the job.

Liquid co2 at some pressure will be a lot more expanded air than air at that pressure, so this may not be a valid task, your life may matter a bit.

The manufacturer may have a different size bag or other way to vary the size.



Sent from my SM-G781V using Tapatalk

 

[B2]

The following does not answer your question, but provides an alternative method of getting the air out of your vest resonably quickly.

I scuba dive and use a BCD (Buoyancy Compensator Device). It is a vest that is inflated to the amount that is needed to offset the buoyancy of the body and weighs etc that one wears. Hence, when inflated it your buoyancy is compensated. Hence you nether float up or down, but just hover in the water. So it is filled via valve either from the mouth by blowing or from the tanks pressure regulator and can be filled quickly (but is not meant to be filled fast as a car air bag) . The BCD vest is of strong woven material, straps and buckles... and inside of this an rubber bladder. The point is that it holds the air during a drive and this can last for a long time. If it leaks you just add a little air. If you dive deeper the air compresses the volume of the vest and you may need to add more air to reinflate it and have the same buoyancy. As you rise the pressure is less and the bladder will become larger and increase the buoyancy so you let some air out as you come up. However, when you want to let the air out a simple spring valve is pulled back to allow the air pressure to push the valve open to escape from the body/badder of the vest. A string and a bob is tied to this rubber valve and hangs out making it easy to get your hand on when you want to let the air out. If you pull hard it comes out fast. Of course these parts must put up with the salt of the sea so are either stainless or non-metallic (rubber or plastic of some form). I use a minimalistic dive-rite model vest. For every 32 foot of depth of diving you pick up an atmosphere of pressure so at a 100 foot dive this is about 50PSI. However, these valves are much stronger than this.

https://www.diverite.com/products/wings/hydro-lite-bcd/ Some BCDs.

If you look at the picture in the next url you will see the valve, string, and bob at the lower right hand side of this part of the vest. https://www.diverite.com/products/wings/voyager-series/

If you google the phrase "scuba bcd dump valve repair" you will see lots of pictures of the portion of the valve that is easily replaced. Also at the following url you will see how the rest of the valve is installed into the rubber bladder. It is similar to patching an inner tube.

https://www.kirkscubagear.com/shop/scuba-accessories/safety/scuba-fix/ Also, lots of You Tube videos available.

Scuba Diving is fun and pleasant and yet it is all about safety. So you want equipment that does not fail!!! Keep it as simple as possible and there are fewer things to go wrong.

Dave L

 

[Geswearf]

I have seen similar to the Amazon link, they work well for adding air to things, use a standard tap.

Stupid questions.

The Helite Turtle 2 vest is a garment that is worn by motorcyclists, horseback riders, and others to mitigate injury in case of a fall. The vest I'm describing has a tether that is fastened to the motorcycle or saddle (newer versions are electronic with accelerometers and sensors) that triggers a spring loaded device that punctures the CO2 cartridge to inflate the vest's bladder. The buckles that fasten this vest are looped on long pieces of webbing faced with velcro. The user adjusts each of three straps (that hold the male and female plastic buckles) to fit his body. This is done with the vest deflated. Having...errrr....tested mine, I found it to be much too tight when it was inflated and I could barely breathe.

Other folks have made the gadget I described - which is putting an automotive wheel air valve (Schrader valve) on a spent cartridge in order to inflate the vest to adjust the fit when inflated. Helite-USA told me the internal pressure immediately after inflation with the cartridge is 6 psi. I want to use a bicycle tire pump to inflate the vest to a firm level - say 4 psi max in order to help my friends adjust the straps. Since at least one acquaintance of mine was injured when his vest was triggered due to the vest being too tight, there is value in being able to adjust the straps properly while it is inflated.

It is possible I am opening myself to some liability, however this project was initially for my use only. I will offer it to my friends who own the vest for their use. If they choose to use it, I suspect my responsibility is low, but I'll ask a friend in the club who is a lawyer. As I said, the vest is supposed to be adjusted by the owner.

Note, my drilling and tapping a spent cartridge is the easiest way for me to adapt a hand bike pump to the 5/8-18 UNF thread on the nose of the cartridge.

Thanks for the warning, I understand what you are saying.

 

[Geswearf]

The following does not answer your question, but provides an alternative method of getting the air out of your vest resonably quickly.

The Helite vest I have, and other motorcycle airbag vests/racing suits are self deflating over a several minute period of time. They are really designed to protect you in the first few seconds of a crash, not hold air for hours. I'm not alone feeling embarrassed when dropping the bike leads to the spectacle of a formerly slim guy now looking like the Michelin Man. The vest is fairly easily unbuckled when inflated, and removing the air can be hastened by opening the velcroed pouch and unscrewing the now punctured CO2 cartridge. Then the vest collapses to its former size in seconds. However, if a user simply waits for a few minutes, the vest will self deflate.

I am familiar with BC's - I used to dive.

 

[Eddyde]

Looks like ⅛ Pipe but check the thread count as NPT and BSPT are only one thread apart.