MK 5 turret retainer

[Luis H]

They are now in the store:

Shop Online

There is no way that Bryan could have had them made for the same price that Scubapro paid. I think at $15 they are very reasonable.
When we had them made as a group they cost us about $13 and we had to pre-order them.

 

[guiness]

now exhaust tees and diaphram covers and the mk 5/109 can last forever

 

[elan]

They are now in the store:

Shop Online

There is no way that Bryan could have had them made for the same price that Scubapro paid. I think at $15 they are very reasonable.
When we had them made as a group they cost us about $13 and we had to pre-order them.

Yeap the price is very reasonable. Cannot complain

 

[Couv]

Well done Bryan and Luis.

A while back we were discussing the proper torque for this retainer. SP shows a torque of 35-45 inch pounds with an * that points to an engineering note to replace the brass retainer with a SS; however the note makes no differentiation in the torque value for brass vs. SS.

The MK10 has two torque values, 35 in lbs for brass and 70 in lbs for SS.

So Luis, should we bump up the torque for the SS (if so how much) or will 35in lbs be enough load to keep it secure?

Thanks,

Couv

 

[Zung]

Because of the horror stories told on this board, I instinctively torqued even the retainers of my MK20's to 40-ish in.-lbs, even though I think they're stainless steel. I have 5 pieces with about 50 dives each, and so far so good, nothing got lose.

So maybe 50 in.-lbs would be a good starting point.

 

[ams511]

Do you guys use loctite on the part?

 

[Zung]

Nooooo!
I put a bit of lube on the threads instead - Makes removal a lot easier!

 

[Luis H]

In this application the 5/16-24 bolt is not clamping anything. What I mean is that there is no clamping force needed to clamp parts together.

The head of the bolt is just a stop and it is not trying to clamp parts together to keep them from sliding. It actually has a low friction washer under the head to allow it to slide.

The only purpose for the torque it to keep the bolt from unscrewing and backing out.

As long as you don’t go crazy rotating the swivel or expose the regulator to a high vibration environment, there are only minimal forces trying to unscrew the bolt. Also regular inspection should expose a loose screw. Look at the gap or any change in the amount of play of the swivel.


I looked at some of my old calculation, and based on that I would keep the torque on the MK-5 SS bolt between 35 to 40 in lb.

I would assume that Scubapro was not addressing the torque on the brass bolt since it is telling the customer not to use them.

I don’t know the actual size of the bolt on the newer regulators (Mk-10 and forward), but my understanding is that they are larger. The strength area is a function of the diameter square. Therefore, it doesn’t take much of an increase in bolt diameter to substantially increase its strength.


Zung,

I would not use lubricant on those threads.

There are two reasons to use lubricant: control corrosion, including galvanic corrosion and to increase the theoretical clamping force for the same torque value.

As I mentioned clamping force in itself is not an issue, but in some cases it could add locking ability. In this case I think you get better locking if you don’t lubricate it. As you mentioned the lubricant is reducing the locking purpose of torquing it.

Corrosion should not be much of an issue either since the threads should always be dry.