Wing nuts or lock nuts?

[Jack Hammer]

I use whatever is on the tanks I grab, usualy wingnuts or a variety of different delrin nuts from several manufacturers. If you press down on the center spine of the plate while tightening your fasteners they don't come loose.

 

[JohnnyC]

Split lock washers don't actually do anything. NASA and the USAF both did studies on the efficacy of lock washers. When it comes to "locking," they don't.

If you want to prevent loosening backplate bolts, either use thread locking compound, nylon-insert lock nuts, understanding that with repeated use cycles they will loose their "locking" ability, or drill the bolt for a backup like an r-pin.

I just make mine hand tight, then push down on the plate while tightening the wingnuts with a homemade wrench.

 

[Compressor]

Interesting that there is a variety of ways to do things. I appreciate all the input given so far.

 

[JohnnyC]

You can make these yourself with the appropriate sized socket or pipe and a 4.5" grinder with a new rock disk. If you have the capability, weld a little t-handle on top or through. Works great.

https://www.glaciertanks.com/img-WN-TR-SOCKET-1.jpg

 

[Lorenzoid]

My aluminum plate has just enough flex that it has somewhat the same effect as a lock washer when I crank down the wingnuts, which never come loose. With my steel plate, yeah, the wingnuts loosen now and then. I haven't tried lock washers or nyloc nuts yet. Watching this thread for suggestions.

 

[Wookie]

Split lock washers don't actually do anything. NASA and the USAF both did studies on the efficacy of lock washers. When it comes to "locking," they don't.

True they don't lock. But they don't "do nothing" either. They compensate when the fasteners do loosen.

http://hillcountryengineering.com/w...it-Lockwashers-Separating-Myth-from-Truth.pdf

 

[Diving Dubai]

I personally use the Dive Rite Screws now. The O-ring is the locking device. Properly tightened they've never come loose.

Before that I used to use a coach bolt with Nylock nut. Good solution as long as you keep the required spanner/ socket handy to remove them.

I've never now use wing nuts, they generally aren't' made to good tolerances. Part of the mechanical locking is formed by the opposite tensile forces on the nut and bolt threads. Wing nuts just don't.

I only remove my bladder in the winter when moving it to a plated rig - but it is checked frequently.

The only time I've ever had a plate/sti come loose and wobble on my back is when I used a wing nut years ago

 

[Diving Dubai]

Of course if ya'll want to be sure...

You can always wirelock - brings back memories when had to wire lock complete turbine discs on fighter jets - that really was dull

 

[TrimixToo]

Geez, fellas, if you want to be sure, ya gotta double-nut 'em, tighten 'em up 'til they just start to strip, go back a quarter turn, and then *weld* 'em. Everything *else* is just taking a chance. Isn't it? Here, hold my beer while I show ya...

For backmounted doubles anything more than flat washers and wingnuts is just silly. They don't come loose (as in "off"), as long as they were well-snugged before the dive. They might be less than finger tight; but seriously, folks, nothing is going to make the things rotate seven or more times to come off while you're diving. Not even one of them, much less both of them.

 

[JohnnyC]

True they don't lock. But they don't "do nothing" either. They compensate when the fasteners do loosen.

http://hillcountryengineering.com/w...it-Lockwashers-Separating-Myth-from-Truth.pdf

If there's enough vibration or force to overcome the initial torque of the fastener, the minor friction of a helical lock washer once the fastener is not under tension is not going to stop movement of the fastener, and movement of the joint itself. I'm curious what they based their statement off of, because empirically and experimentally it's not true. By the time the fastener has lost torque and begins to loosen, you've lost like, 90% of the clamping force of the joint itself. There's nothing to compensate for because the joint has already failed to the point that it's entirely ineffective. It's certainly not going to stop the fastener from being lost.

Helical spring lock washers actually increase the rate of loosening. Want to keep a nut from coming off a bolt? Proper torque. Absolutely no helical spring lock washers! Use a flat washer to increase the bearing surface.