Help with aka60/ida thread size

**fireman** · 27th December 2006, 00:04

Any information on the thread sizes on the various fittings on the Russian rebreathers. I Just got my Orca and need to do some replumbing. Not to mention cylinder filling.

**Dave Sutton** · 27th December 2006, 01:38

First, slow down and breath a little.... ;-)

There is VERY little re-do required on the AKA-60. If you carry a bailout bottle offboard and run your suit/wings from it, and don't need to tap into the rigs pneumatics for this, there is *no* work to be done other than to add harness, wings, and P-Connector for the (mandatory) PP02 meter of choice. The pneumatics work fine *as is* so less modification = a better rig, the way I see it. Now, if you want to turn it into a CCR? Different deal... but not a hard one.

If you *do* need to tap into the pneumatics, you can cut lines and use metric Swagelok fittings to "T" things off and take the metric tubes to SAE threads. You can tap the rigs HP crossover line between the two cylinders, for example, run a HP line to a ball valve (on/off) and then to a DIN female port and add a first stage at that port, and run bailout, suit, wings, etc., from that regulator and be able to isolate the port from main supply with the ball valve. It's what I did to my FGT-1D and it works on th AKA as well. Thinbk the tubes are 7mm, might be 6mm, easy to measure and Swagelok has the fittings. 6mm is a normal metric tube fitting, 7mm is almost the same as 3/16 SAE tube and 3/16 fittings work fine.

To turn it into a CCR, cut each tube leading from the bottles, use a Swagelok tube to SAE pipe thread fitting, run that to a DIN female port, add regulators, and go for it from there. Feed gas back to the ADV from the new regulator by reversing the fittings, use normal hose with 1/8 PT male on the end to a Swagelok SAE female to metric tube fitting and add that to the (cut) line to the ADV. Piece of cake. Or you *could* just box it, send it here, and get it back as a CCR all done and tested..... I probably have nearly all the parts in stock.

The port on the bottom of the rig is designed to umbilical feed it, you "can" fill it there but the rig is going to "run" (flow) if you feed gas there so best not. Better to remove and fill the cylinders out of the chassis.

The threads on the cylinders are just a 3/4 inch SAE thread. They are the *same* as the female thread on the inside of a normal SCUBA cylinder (!!). They are NOT metric, as they are the German 02 thread and that thread is a BSP (British Straight Pipe) one that is based on SAE dimensions, not metric. The thread is a pre WW-II standard one that is still used. You can probably find the fitting from W+S Safety in Germany.

With that said, I probably have an extra filler adapter, let me look on the slab in the Little Diveshop of Horrors tomorrow.

Congratulations on getting a nice rig, Good system as-is as a SCC rig and unlimited potential as a CCR conversion platform.

Dave

**fireman** · 27th December 2006, 02:05

Hey thanks for the info. I am going to use it as an scr for a while then KISS it.
In the process of messing around with my new toy, I notice some white stuff inside some of the stainless fittings. The external soft hose, at the bottom end has a patch of corrosion, at the top I actually broke the fitting that the gage screwed into...crap.
The valve on one of the bottles seems to not turn well the other looks fine.
I think it is a very nice rig, unused but old.

When it comes time to ccr it you wouldn't recommend keeping the existing reg for the O2 side?

**Dave Sutton** · 27th December 2006, 21:08

Quote: (Originally Posted by fireman)

Hey thanks for the info. I am going to use it as an scr for a while then KISS it.
In the process of messing around with my new toy, I notice some white stuff inside some of the stainless fittings. The external soft hose, at the bottom end has a patch of corrosion, at the top I actually broke the fitting that the gage screwed into...crap.
The valve on one of the bottles seems to not turn well the other looks fine.
I think it is a very nice rig, unused but old.

When it comes time to ccr it you wouldn't recommend keeping the existing reg for the O2 side?

Ahhh.... Russian pre-assembled kits. Forgot to mention this bit: Russian *everythings* are not assembled with care, they are assembled to make sure all of the parts are there and for little other reason. It is *expected* that the person person putting it into service will *completely* disassemble it, lube it, reassemble it, and adjust it. We found this out with the (36) sidecar motorcycles I imported new from Moscow. The first one ran like crap, and when I wrote my suplier, he was agast: "You didn;t actually START it, did you?" he asked? Naturally I assured him that I had... "NO!!" he wrote back.. "The valves will toutch... the carbs need to be taken apart and cleaned... the bearings aren't greased....!!" I learned from this that Russians used to buy a (car, motorcycle, etc) and then pay a mechanic to totally overhaul it to begin with. The rebreather is exactly the same. It needs a TOTAL tear down and lube before being used.

If I converted one to a CCR I'd junk all of the pneumatics so I knew what I was working with. The mass flow of te thing is about 20X what you need for KISS 0 flow, so don't even dream of using it CCR with that regulator setup.

Dave

montyg · 28th December 2006, 07:53

Quote: (Originally Posted by Dave Sutton)

First, slow down and breath a little.... ;-)

Thinbk the tubes are 7mm, might be 6mm, easy to measure and Swagelok has the fittings. 6mm is a normal metric tube fitting, 7mm is almost the same as 3/16 SAE tube and 3/16 fittings work fine.

Dave

FWIW, the tube on the IDA-71's are 5/16ths, which is just a little bit smaller than 8mm. Maybe these ones use the same size tube?

rgds
monty

empressdiver · 13th January 2007, 18:45

Have you found out what filling adapter is needed and the outlet thread size of the tank valves for the AKA-60?

Skipbreather · 14th January 2007, 19:24

Quote: (Originally Posted by empressdiver)

Have you found out what filling adapter is needed and the outlet thread size of the tank valves for the AKA-60?

A fill adapter that fits the umbilical port is easy enough to build w/ a lathe. I built one for my AKA60 by starting with standard brass fittings for filling CO2 bottles (CGA 320). It is the same thread (14 threads per inch) but a bit undersize (0.825 inch). The coupler nut is put into the lathe, internal threading tool aligned w/ the existing thread, and the interior is enlarged slightly to fit to about 0.860 or so.

CO2 parts are inexpensive & widely available at most welding supply shops. If not in stock, ask them to order Western Enterprises part numbers CO-2 (the nut), CO-8 (the nipple), and CO-6 (Teflon washer).

Ken

**fireman** · 14th January 2007, 23:50

Are the threads 55 or 60 degrees--bspp or us?

**Dave Sutton** · 15th January 2007, 01:47

Makes no difference because they *work*....

Dave

empressdiver · 13th February 2007, 17:42

I have also just taken delivery of my AKA-60 a few days ago and need to buy a filler adapter for the tank valve outlet thread.

I took a tank to three pneumatics parts suppliers but they didn't have anything that matched and they couldn't tell me what the correct thread was. They tried several including a 1/2" BSPP but it was too small. They also said it wasn't metric since the diameter was a little under 22mm. And I don't have a lathe.

So now I'm stuck at square one. The tank valve outlet has 14 threads/inch and the diameter is 0.855" or about 21.7mm. Thr thread is parallel. Is there a proper thread available?

Dave, do you have another filler adapter in your dive shop somewhere that you can sell to me?

Ron

27th December 2006, 00:04	#1 (permalink)
fireman rEvo combat swimmer Current Rebreather/s: rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Nov 2006 Location: chicago Posts: 550	Help with aka60/ida thread size Any information on the thread sizes on the various fittings on the Russian rebreathers. I Just got my Orca and need to do some replumbing. Not to mention cylinder filling.
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27th December 2006, 01:38	#2 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,913	Re: Help with aka60/ida thread size First, slow down and breath a little.... ;-) There is VERY little re-do required on the AKA-60. If you carry a bailout bottle offboard and run your suit/wings from it, and don't need to tap into the rigs pneumatics for this, there is no work to be done other than to add harness, wings, and P-Connector for the (mandatory) PP02 meter of choice. The pneumatics work fine as is so less modification = a better rig, the way I see it. Now, if you want to turn it into a CCR? Different deal... but not a hard one. If you do need to tap into the pneumatics, you can cut lines and use metric Swagelok fittings to "T" things off and take the metric tubes to SAE threads. You can tap the rigs HP crossover line between the two cylinders, for example, run a HP line to a ball valve (on/off) and then to a DIN female port and add a first stage at that port, and run bailout, suit, wings, etc., from that regulator and be able to isolate the port from main supply with the ball valve. It's what I did to my FGT-1D and it works on th AKA as well. Thinbk the tubes are 7mm, might be 6mm, easy to measure and Swagelok has the fittings. 6mm is a normal metric tube fitting, 7mm is almost the same as 3/16 SAE tube and 3/16 fittings work fine. To turn it into a CCR, cut each tube leading from the bottles, use a Swagelok tube to SAE pipe thread fitting, run that to a DIN female port, add regulators, and go for it from there. Feed gas back to the ADV from the new regulator by reversing the fittings, use normal hose with 1/8 PT male on the end to a Swagelok SAE female to metric tube fitting and add that to the (cut) line to the ADV. Piece of cake. Or you could just box it, send it here, and get it back as a CCR all done and tested..... I probably have nearly all the parts in stock. The port on the bottom of the rig is designed to umbilical feed it, you "can" fill it there but the rig is going to "run" (flow) if you feed gas there so best not. Better to remove and fill the cylinders out of the chassis. The threads on the cylinders are just a 3/4 inch SAE thread. They are the same as the female thread on the inside of a normal SCUBA cylinder (!!). They are NOT metric, as they are the German 02 thread and that thread is a BSP (British Straight Pipe) one that is based on SAE dimensions, not metric. The thread is a pre WW-II standard one that is still used. You can probably find the fitting from W+S Safety in Germany. With that said, I probably have an extra filler adapter, let me look on the slab in the Little Diveshop of Horrors tomorrow. Congratulations on getting a nice rig, Good system as-is as a SCC rig and unlimited potential as a CCR conversion platform. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com Last edited by Dave Sutton : 27th December 2006 at 01:42.
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27th December 2006, 02:05	#3 (permalink)
fireman rEvo combat swimmer Current Rebreather/s: rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Nov 2006 Location: chicago Posts: 550	Re: Help with aka60/ida thread size Hey thanks for the info. I am going to use it as an scr for a while then KISS it. In the process of messing around with my new toy, I notice some white stuff inside some of the stainless fittings. The external soft hose, at the bottom end has a patch of corrosion, at the top I actually broke the fitting that the gage screwed into...crap. The valve on one of the bottles seems to not turn well the other looks fine. I think it is a very nice rig, unused but old. When it comes time to ccr it you wouldn't recommend keeping the existing reg for the O2 side?
(Offline)

27th December 2006, 21:08	#4 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,913	Re: Help with aka60/ida thread size Quote: (Originally Posted by fireman) Hey thanks for the info. I am going to use it as an scr for a while then KISS it. In the process of messing around with my new toy, I notice some white stuff inside some of the stainless fittings. The external soft hose, at the bottom end has a patch of corrosion, at the top I actually broke the fitting that the gage screwed into...crap. The valve on one of the bottles seems to not turn well the other looks fine. I think it is a very nice rig, unused but old. When it comes time to ccr it you wouldn't recommend keeping the existing reg for the O2 side? Ahhh.... Russian pre-assembled kits. Forgot to mention this bit: Russian everythings are not assembled with care, they are assembled to make sure all of the parts are there and for little other reason. It is expected that the person person putting it into service will completely disassemble it, lube it, reassemble it, and adjust it. We found this out with the (36) sidecar motorcycles I imported new from Moscow. The first one ran like crap, and when I wrote my suplier, he was agast: "You didn;t actually START it, did you?" he asked? Naturally I assured him that I had... "NO!!" he wrote back.. "The valves will toutch... the carbs need to be taken apart and cleaned... the bearings aren't greased....!!" I learned from this that Russians used to buy a (car, motorcycle, etc) and then pay a mechanic to totally overhaul it to begin with. The rebreather is exactly the same. It needs a TOTAL tear down and lube before being used. If I converted one to a CCR I'd junk all of the pneumatics so I knew what I was working with. The mass flow of te thing is about 20X what you need for KISS 0 flow, so don't even dream of using it CCR with that regulator setup. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
(Offline)

28th December 2006, 07:53	#5 (permalink)
montyg Monty Guest Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Feb 2007 Location: Cape Town, South Africa Posts: 242	Re: Help with aka60/ida thread size Quote: (Originally Posted by Dave Sutton) First, slow down and breath a little.... ;-) Thinbk the tubes are 7mm, might be 6mm, easy to measure and Swagelok has the fittings. 6mm is a normal metric tube fitting, 7mm is almost the same as 3/16 SAE tube and 3/16 fittings work fine. Dave FWIW, the tube on the IDA-71's are 5/16ths, which is just a little bit smaller than 8mm. Maybe these ones use the same size tube? rgds monty
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13th January 2007, 18:45	#6 (permalink)
empressdiver New Member Current Rebreather/s: Other SCR Other Rebreather/s: Other SCR Join Date: Dec 2005 Location: Toronto, Ontario, Canada Posts: 39	Re: Help with aka60/ida thread size Have you found out what filling adapter is needed and the outlet thread size of the tank valves for the AKA-60? __________________ If not now, when?
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14th January 2007, 19:24	#7 (permalink)
Skipbreather Reads the fine print Current Rebreather/s: Megalodon Home Build Other Rebreather/s: Not Bought Yet MK 15.X Home Build Join Date: Mar 2005 Location: Chicago, Illinois, USA Posts: 584	Re: Help with aka60/ida thread size Quote: (Originally Posted by empressdiver) Have you found out what filling adapter is needed and the outlet thread size of the tank valves for the AKA-60? A fill adapter that fits the umbilical port is easy enough to build w/ a lathe. I built one for my AKA60 by starting with standard brass fittings for filling CO2 bottles (CGA 320). It is the same thread (14 threads per inch) but a bit undersize (0.825 inch). The coupler nut is put into the lathe, internal threading tool aligned w/ the existing thread, and the interior is enlarged slightly to fit to about 0.860 or so. CO2 parts are inexpensive & widely available at most welding supply shops. If not in stock, ask them to order Western Enterprises part numbers CO-2 (the nut), CO-8 (the nipple), and CO-6 (Teflon washer). Ken __________________ "Entropy RULES! Enjoy the interim."
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14th January 2007, 23:50	#8 (permalink)
fireman rEvo combat swimmer Current Rebreather/s: rEvo Other CCR Other Rebreather/s: rEvo Other CCR Join Date: Nov 2006 Location: chicago Posts: 550	Re: Help with aka60/ida thread size Are the threads 55 or 60 degrees--bspp or us?
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15th January 2007, 01:47	#9 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,913	Re: Help with aka60/ida thread size Makes no difference because they work.... Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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13th February 2007, 17:42	#10 (permalink)
empressdiver New Member Current Rebreather/s: Other SCR Other Rebreather/s: Other SCR Join Date: Dec 2005 Location: Toronto, Ontario, Canada Posts: 39	Re: Help with aka60/ida thread size I have also just taken delivery of my AKA-60 a few days ago and need to buy a filler adapter for the tank valve outlet thread. I took a tank to three pneumatics parts suppliers but they didn't have anything that matched and they couldn't tell me what the correct thread was. They tried several including a 1/2" BSPP but it was too small. They also said it wasn't metric since the diameter was a little under 22mm. And I don't have a lathe. So now I'm stuck at square one. The tank valve outlet has 14 threads/inch and the diameter is 0.855" or about 21.7mm. Thr thread is parallel. Is there a proper thread available? Dave, do you have another filler adapter in your dive shop somewhere that you can sell to me? Ron __________________ If not now, when?
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