Scubapro R190/R380/R390 Nylock nut

[NJDiver07866]

Thanks again everyone for your help in the past.
Few questions on the nylock nut on the scubapro 2nd stage.

In the manual it says to disregard and throw out the nut every time you take it off. Is there anything special about this nut? Meaning I have a local shop that caries a bunch of odd shape fasteners. I wanted to pick up a ton of these nuts. My nut *no jokes please* has like a purple nylon looking thread on it.. the one pictured in the kit is white.. so I'm thinking I can just pick up the same type 1/4 nut at a specialty shop?


http://imgs.inkfrog.com/pix/hailais/Kit-R190.jpg

If the directions say replace every time I will. I would like to know why.. I guess the nylon does not last too long? But just wanted to get your guys thoughts and experiences on this nut. Or should I just stick to the scubapro nuts. I'm pretty sure they just repackage a standard 1/4 nyloc nut, don't want to make any assumptions...

Thanks for your help, I took the 2nd stage apart, with the diagram next to me. Was a bit nail bitting at first, but all kidding aside.. not really that bad. Cleaned it all up and put it back together, adjusted the cracking pressure, measured it with a magnehelic guage and everything is working just great!!

Thank you everyone for your help...

[NJDiver07866]

By looking online.. There is a bunch of variations of a 1/4 nyloc nut. Thread size, face size etc..

McMaster-Carr (http://www.mcmaster.com/#nylock-nuts/=1y5jnd)

I think this is them. Just have to figure out the Inch Thread size & the overall length (9/64 or 7/64).

Will post if I find anything more.

Thanks,
Rich

[NJDiver07866]

and I'm assuming stainless steel would be the better one instead of the steel w/ zink finish..

[DA Aquamaster]

You definitely want stainless steel so that it will not corrode in place.

If you have to re-adjust the nut or remove it, then replace it as they don't hold as well when re-adjusted or reused. The reason is simple enough - if it unscrews the lever falls off and the reg will stop delivering gas. A failure to deliver gas failure is bad news, so a new ny-lock nut is cheap insurance.

[awap]

If it does unscrew, cracking effort will go to hell in a handbasket well before the the nut and lever fall off. I got a supply of nuts from M-C but old habits die slowly. I reuse these nuts and have never had any problem.

[cbmech2]

The nyloc nut has the nylon insert that when screwed down helps to hold the nut in place. Although some may choose not to replace it, replacing the nut is cheap insurance against the nut possibly coming loose. It is also designated as an annual replacement part, hence the reason why it is included in the annual service kits for those regulators where it is used. I am with DA in his recommendation to get a stainless nut for a replacement. The last thing you want is to have the nut weld itself to the threads of the poppet.

[Packhorse]

Next you will be wanting to buy a sheet of neoprene and a hole punch to make new seats!

Would you really trust your life to a service kit that cost you less than $1 to assemble?

[awap]

Next you will be wanting to buy a sheet of neoprene and a hole punch to make new seats!

Would you really trust your life to a service kit that cost you less than $1 to assemble?

I do about that with no problems. But I use duro 80 viton rather than neoprene. I have been using them for about a year now. I doubt if those 2nd stage kits cost the manufacturer even a dollar. My homemade seats are costing me about a penny each (a $6 sheet will make over 600 seats). The o-rings in those kits should also be only pennies each in quantity. And the lock nut is maybe a nickle. Packaging might double the cost. Yet, the retail price for those kits runs $8 to $15 each, if you can find a retailer who will even sell them. And that is the biggest rub. Most manufacturers want to force you to spend $100 (parts & labor) for what amounts to a couple dollars worth of parts. :popcorn:

[NJDiver07866]

Thanks for the help folks. I'm totally with you guys, I'm not trying to save a few bucks. With just getting into DIY and having a set of all new tools from Scubatools I have taken apart the reg and put it back together a 1/2 dozen times or so (i bet it gets old, but now its fun and new). Not looking to go cheap, and will replace the nut every time. Just thought there would be a better way instead of buying a new scuba pro kit for $22 bucks a shot. So if anyone has the exact size so I can get a few dozen of these nuts it would help out greatly.

I'm going to the special nut shop to see if the guy can measure my nuts to get me nice shiny nuts so my rod won't fall off. But if anyone knows the size of my nuts off the top of their head, It would help out to verify that the guy measuring my nuts is right. (OCD rebreather training.. worst thing I fear is putting the wrong sized nut that close to my mouth and having my rod fall off)

I won't go as far as punching out my own seats, but kudos for the creativity!!!

Thanks folks will post back

[NJDiver07866]

OK nut measured and confirmed. I ordered it from the McMaster site.
Part #91831A006
1 Pack 18-8 Stainless Steel Nylon-insert Hex Locknut5-40 Thread Size, 1/4" Width, 9/64" Height.

$4.92 for a box of 100.. so ~ 5 cents a nut.

Thanks all for the help...

[mattboy]

I've seen the seats that Awap made and they look and work perfect. They're so cheap you could replace them after every dive if you wanted to. When is he going to start making the balanced seats, I wonder? How about replacement seats for the D series? HP seats for the Mk5/10?

There are other ways to keep the nut in place on the R190 if you're in a jam and don't have a new nyloc nut. You can use two regular nuts, one as an adjusting nut, one as a lock nut (if there are enough threads) or you can use some fingernail polish, even a tiny spot of the weaker loctite would work.

[captain]

[QUOTE=Packhorse;4429384]Next you will be wanting to buy a sheet of neoprene and a hole punch to make new seats!

QUOTE]

Did that many times, works like a charm.

[NJDiver07866]

Thanks for the help. Now that I got the right nut size... then I will just stock a bunch of them in my box....

Just for S&G's what tool do you use to punch the seats? Like a leather punch or a Metal punch?

http://www.signs-derby.com/i//punch_kit.jpg

And is there any particular retailer you get the neoprene sheets from? Any specifics on the type or is it simply called neoprene sheets... I have to measure mine and see if I can pull this off...

Raw Materials > Rubber > Sheets and Strips > Rubber,Neoprene,3/32 In Thick,12 x 12 In : Grainger Industrial Supply (http://www.grainger.com/Grainger/items/1DWJ1?cm_mmc=Google%20Base-_-Raw%20Materials-_-Rubber-_-1DWJ1)

You guys are too much... Thanks for the help...

[awap]

I bought mine from McMaster-Carr: McMaster-Carr (http://www.mcmaster.com/)

8985K125 1 Each High-strength Weather-resistant Epdm Rubber, 1/16" Thk, 2"w, 36"l, 80a Durometer, Black

3424A22 1 Each Small-diameter Hole Punch, 9/32" Hole Diameter, Trade Size 11

I see now I went with the EPDM rather than the viton.

[NJDiver07866]

Thanks AWAP Very intresting...

On the EPDM..intresting.. I read that this what they use standard in the scubapro and other makes.

I know the viton has a higher combustion temp.. but I also hear that it releases pretty nasty gas when it burns.

I paid out the wazoo at a local dive shop to get this regs setup for oxygen service.. when I look at the seat it looks like the same material as stock (EPDM) and not the Brown Vition...

Here are the self ignition temperatures in degrees celcius for the different materials: (Found this on the net.. not sure if it is true)

Will pick up a sheet of the Viton.. do you have anything against the Vition? Or just like the EDPM better? Thanks for the help... I find this all intresting...

Silicone: 218
EPDM: 159
Nitril: 173
Butyl: 208
Viton: 268 - 322
Teflon: 378 - 434

[awap]

Thanks AWAP Very intresting...

On the EPDM..intresting.. I read that this what they use standard in the scubapro and other makes.

I know the viton has a higher combustion temp.. but I also hear that it releases pretty nasty gas when it burns.

I paid out the wazoo at a local dive shop to get this regs setup for oxygen service.. when I look at the seat it looks like the same material as stock (EPDM) and not the Brown Vition...

Here are the self ignition temperatures in degrees celcius for the different materials: (Found this on the net.. not sure if it is true)

Will pick up a sheet of the Viton.. do you have anything against the Vition? Or just like the EDPM better? Thanks for the help... I find this all intresting...

Silicone: 218
EPDM: 159
Nitril: 173
Butyl: 208
Viton: 268 - 322
Teflon: 378 - 434

As I recall, the price of viton was 2 or 3 times higher and I saw absolutely no advantage in viton over the EPDM (both have very similar characteristics in scuba applications). Both should handle recreational nitrox with no problem. Heck, even the neoprene will probably take it just fine. In a 2nd stage, it should never see sufficient concentrations and pressures to be a problem. A 1st stage may be another story.

But I am a cheap bastard. Even at a penny a seat, I flip them once and use both faces. Old habits die hard.

BTW, the color of the material is not a reliable indicator of the composition. While brown is fairly common in viton (o-rings), they can all be easily found in black. And they can be special ordered in just about any color.

[NJDiver07866]

Thanks for the help AWAP...

You are too funny by flipping the seats..... I am really enjoing cleaning and servicing my own gear. The Mk25 had me a bit scared.. but once I got it apart and understood how the MK25 tool worked w/ the bushings it went like butter..

Thanks for the help,
Rich

[cbmech2]

Guess I am a cheap bastard too awap as I just bought my sheet of rubber, the punch and the nylock nuts through McMaster-Carr. Do you have any more of that type of information that you could post or pm me with? Now, if I can crack the code on specific -oring sizes for all of the major manufacturers I will be ready for business once my compressor and test bench is installed in the garage. Will post pics if anyone is interested.

[mattboy]

Couv has some annotated schematics of MK5/10 that show the standard o-ring sizes. I'd like to know the standard sizes for the G250 poppet/balance chamber o-rings (probably tiny metric) and the one on the D400 poppet (slightly bigger).

On a slight hijack, I took apart an old D400 poppet today and I'm convinced that making those seats would not be too difficult.

[cbmech2]

I have a list that I started based on a consolidation of different things I found on the net and put them into an excel spreadsheet (attached).

[couv]

cbmech2

Like the others, I too am a cheap bastard so I do not have the latest version of Xcel, can you post that in an older version?

If you (or anyone) PMs me with an email address where you can receive PDF files and I will try to send you a copy of my annotated drawings.

Viton and EPDM have very long shelf lives and that's why they are a better choice for us DIY guys than Nitril or most rubber based seal material. Viton is more expensive but has more consistency in the hardness from one o-ring to the next. Silicone is good in applications where you will not need any lubricant, but in addition to being a cheap bastard, I like keep things simple by stocking as few different materials as possible.

Matt, the S-wing poppet is probably a -oo1 1/2 …very hard to find so I have been using a -002 and as yet no problems. I do not have any scrotum type regulators, but if the poppet o-rings are slightly larger than the G250 poppet o-rings, then in all probability they are -002. I'll bring some to you on the upcoming FGB trip.

couv

[awap]

Not to be outdone on cheap by the amateurs above, I don't have any excel (or office) SW. How about a good old .txt file? I could probably spring for .pdf:D

[muddiver]

I have a list that I started based on a consolidation of different things I found on the net and put them into an excel spreadsheet (attached).

Sweet O-ring chart.

To the OPs original question: Nylock nuts are a jamb type nut. The nylon inside the nut acts as the threads and when screwed onto the correct size threaded post the grooves cut into the nylon act as a lock washer or jamb nut. It only works once, then the mater looses its resilience and you also gouge some of the nylon out in the first run so there is not enough the hold a second time, thus defeating the purpose of the nut. These are place holder nuts, not load bearing.

If the self locking nut is not white insice, I suspect that they are not nylon, but possably an oxygen compatable material. As long as you don't dive any mix over 21% O2 it sould not make a difference. Rebuild away. ;)

If you are being cheap and you dive Nitrox or mixed gas, changing to run of the mill hardware in a regulator is not very smart. :no: Not only are you installing non-oxygen compatable materials, common hardware is not clean and has left over hydrocarbons on it from the manufacturing process. My statement only holds for the first stage. The second stage is on the low pressure side and unlikely to be subjected to adiabatic heating.

[USFishin]

Does anyone know if the locknuts discussed here in this thread (18-8 Stainless Steel Nylon-insert Hex Locknut 5-40 Thread Size, 1/4" Width, 9/64" Height) are a SCUBA industry standard size? I have Oceanic regulators and have rebuilt them once with the annual service kits. I am considering getting the EPDM sheets, punch, and locknuts from McMaster. I have an old locknut from the rebuild and could go measure it I guess but I figured I'd ask if anyone knew if this size is the same for other regs.

[cbmech2]

Awap,
Been MIA for a spell. Been working on a hell of alot of regs and actually doing some diving. The text file and the MS Excel 97-2003 version is attached. Feel free to add to it as it is a work in progress. Enjoy!

[NJDiver07866]

Flammability and sensitivity of ... - Google Books (http://books.google.com/books?id=m6-IjjQn2GoC&pg=PA319&lpg=PA319&dq=is+nylon+oxygen+compatible&source=bl&ots=W-sQply_XR&sig=gEyDQK1qkWPV2NUBIl1UXm7y-LM&hl=en&ei=2eCsSo3NDM-ZlAeDnezRBg&sa=X&oi=book_result&ct=result&resnum=1#v=onepage&q=is%20nylon%20oxygen%20compatible&f=false)

Nylon is 'Oxygen' happy in my 2nd stage at these pressures... Intresting reading if it is a rainy day...

I simple green everything and run 100% through my regs. I use EPDM instead of Viton. Prepare to beat me up now :)

[BlueWaterDiving]

Did you find your nuts that you were looking for???? If not PM me your address and I will send you some nuts:D

[USFishin]

Does anyone know if the locknuts discussed here in this thread (18-8 Stainless Steel Nylon-insert Hex Locknut 5-40 Thread Size, 1/4" Width, 9/64" Height) are a SCUBA industry standard size? I have Oceanic regulators and have rebuilt them once with the annual service kits. I am considering getting the EPDM sheets, punch, and locknuts from McMaster. I have an old locknut from the rebuild and could go measure it I guess but I figured I'd ask if anyone knew if this size is the same for other regs.

I measured a nut from one of my Oceanic Delta 3's and it is the same size as noted above. I am thinking that this size is probably somewhat of an industry standard. The nut size on the Oceanic Delta 3/4 and Alpha 7/8 are all the same size.