Question Do I need book screws if I’m using a wing + backplate without a STA?

[DR3AD]

on this subject can anyone explain why some book screws have an o ring on them (both sides, male and female) and others don't? Curious, as I want to get some book screws to see if I like them before experimenting with zip ties.... do the o rings matter? are they for grip to the backplate?

 

[lowwall]

on this subject can anyone explain why some book screws have an o ring on them (both sides, male and female) and others don't? Curious, as I want to get some book screws to see if I like them before experimenting with zip ties.... do the o rings matter? are they for grip to the backplate?

I do not know this, but I can speculate that they could be useful to keep the steel screws heads from galvanically "welding" themselves to aluminum backplates.

Edit: DGX says "metal assembly screws include o-rings to help keep the screw in place."

 

[Shabaday]

The O-rings keep the screw from loosening like a lock washer.
So this past diving I removed the STA and and used book screws to hold everything together...That ended up being no issue...what was an issue was the regulator kept hitting my wife in the back of the head no matter how we moved the tank positioning. I put the sta back on and no issue anymore

 

[Unaware6905]

I don't use the screws. I've built over a 100 set ups over the last 10 years for people. Some wanted them so I put them on. Soon though they ditched them. For convenience to keep from having to reposition the wing when switching tanks a zip tie works just as well, it easily removed, and doesn't leave a head that might come into contact with the cylinder. Depending on the wing and where the roll control ribs are if it has any, a cylinder might end up on the screw. No issue with a zip tie.
All of the plates and wings I've used and most that I have seen with slots, have 3 holes that align with the ones in the plate. Run the zip tie through two of them. Problem solved.

I just asked the same question as the OP, and then found this thread. The zip tie method is genius! Just did it. Easy and cheap to replace if they break, too. Thanks.