Beginner's Guide to Regulators

[halocline]

I wrote a short article several years ago for an online column hosted by my friend and cave instructor extraordinaire Natalie Gibb. I was looking through some old files this morning trying to figure out my MK5 DIN retainer conundrum when I found the article. So I thought some people on this forum might get a kick out of it. Enjoy....

 

[rsingler]

What a great article, halo! Easy reading, concise, and best of all, accurate!

Well done.

Perhaps @The Chairman might consider it for sticky fame in this or the Beginners Forum?

 

[The Chairman]

I don't believe that Natt is allowed to cross-post any of her work.

 

[halocline]

I can ask her, I'll see her in a couple of weeks when I'm down there diving with them.

 

[axxel57]

MK5 DIN retainer conundrum....?

 

[The Chairman]

I can ask her, I'll see her in a couple of weeks when I'm down there diving with them.

Give her my warmest regards. She's a one of a kind resource.

 

[halocline]

MK5 DIN retainer conundrum....?

Thank you for asking, I was wondering if someone would. I have a pair of DIN retainers that appear to be MK5 retainers. They're a few mm longer (approx) than the modern retainers, they have circlips holding the wheel on, and one of them has a filter with a small star washer holding it place. They seem to screw in fine and seat well, and they don't leak. But there was a problem with the circlip pressing against the saddle, maybe the DIN retainers were supposed to work with different saddles. Anyhow, I just took the circlip off as it's only function seems to be keeping the wheel on when the retainer is not installed. The other issue is the small star washer that holds the filter in; it's quite a bit smaller than the star washers used in the yoke retainers, and I don't have any of the smaller ones. So I used a 011 o-ring and that holds the filter in well.

So I think I have working DIN retainers for this pair of MK5s, but I was trying to determine if the ones I have are actually for the MK5, and what the deal is with the circlip (the modern DIN retainers don't have one) when I found that old article.

 

[NotSure]

I sounds like you have the correct DIN retainers. The MK5 yoke bolt is designed to bear on the saddle. The circlip is there so the the DIN bolt will also. Later MK5's that came with a plastic saddle had a brass insert the allowed the saddle to take the torque load. The MK5 should not be used with the MK10 plastic saddle or the saddle wiil crack when torqued.

 

[halocline]

I sounds like you have the correct DIN retainers. The MK5 yoke bolt is designed to bear on the saddle. The circlip is there so the the DIN bolt will also. Later MK5's that came with a plastic saddle had a brass insert the allowed the saddle to take the torque load. The MK5 should not be used with the MK10 plastic saddle or the saddle wiil crack when torqued.

View attachment 457216

Thanks! I actually removed the circlip because I didn't want the saddle to bear any of the torque. There can't be a good reason to want pressure on that saddle, can there? I have the plastic saddles with the brass insert, and one of them is cracked.

What I was looking for was being able to easily and smoothly screw in the retainer until it 'bottoms out' and then apply about 23 ftlbs of torque. Removing that circlip allowed me to do that.

I did compare the inserted end of the DIN retainers I have with the same end of the yoke retainer I pulled out of the MK5, and they looked to be identical.

Edit: I have another, much shorter DIN retainer that I believe is a 200 bar retainer for the MK2. I don't have the wheel for that one, but I like to find one and use the MK2 as a deco reg with a 200bar fitting for a small O2 tank.