Sea & Sea Synch cord connector o ring dimensions

[sherco49]

Hi,
i am checking my camera gear, and i realize that the o rings of the Sea & Sea optical synch cords connector are torn.
Can someone give me their dimensions?
Thank you for you answers

 

[bvanant]

I have been using the ones from Backscatter, or Nauticam. By my measurements, it should be
cross section is 1.8 mm,
OD= 7.05 mm
ID 3.45 mm.

The important bit is the OD. The hole on my S&S strobes is just a bit under 7 mm diameter.
Bill

 

[sherco49]

I have been using the ones from Backscatter, or Nauticam. By my measurements, it should be
cross section is 1.8 mm,
OD= 7.05 mm
ID 3.45 mm.

The important bit is the OD. The hole on my S&S strobes is just a bit under 7 mm diameter.
Bill

Thank you for your answer
you are right, i have to measure the hole diameter to be sure

 

[d^2b]

I remember from a previous search that they are a JIS o-ring size. I actually ended up sanding some larger (N90) ones down, but on the little baggie I wrote JIS S4, so maybe that's correct? That would be 6.5mm OD.

 

[sherco49]

My measurments are

I remember from a previous search that they are a JIS o-ring size. I actually ended up sanding some larger (N90) ones down, but on the little baggie I wrote JIS S4, so maybe that's correct? That would be 6.5mm OD.

6.5 outer diameter looks too small. i measured the optical bore, it is 6.9/7mm. The connector is 6.8mm OD, and 5mm for the groove diameter.
So OD=7 CS=1 o ring should fit

 

[d^2b]

My measurments are

6.5 outer diameter looks too small. i measured the optical bore, it is 6.9/7mm. The connector is 6.8mm OD, and 5mm for the groove diameter.
So OD=7 CS=1 o ring should fit

I agree with you it sounds odd, but compare e.g.

https://www.bhphotovideo.com/c/product/1407130-REG/sea_sea_ss_x_10182_o_ring_s_4_nbr60_for.html

Perhaps the very soft N60 o-rings stretch around the 5mm groove enough that the fit is reasonable?

In any case, it's a low risk experiment, as long as the connectors don't fall out, since they are not actually sealing anything in any housing I've seen with fiber optical connectors.

 

[VsubT]

In any case, it's a low risk experiment, as long as the connectors don't fall out, since they are not actually sealing anything in any housing I've seen with fiber optical connectors.

Great point. I’ve always wondered whether those o-rings actually make a seal or not, since air trapped inside would expand and pop the connectors out as we descend.

Seems like the o-rings are more of a friction fit mechanism than a seal. If I were designing a connection like that, an inset transverse groove on the interior of the receiving cylinder with a longitudinal channel that allows expanding air to escape would make sense. Putting the equalization channel in the connector itself might make more sense from a manufacturing perspective though.

Lance

 

[d^2b]

Putting the equalization channel in the connector itself might make more sense from a manufacturing perspective though.

I hadn't thought about that, but indeed the 3 brands of fiber optic cable I have all have a channel in the connector that goes under the O-ring.

 

[happy-diver]

Maybe some quick stuff

https://www.applerubber.com/src/pdf/section3-o-ring-basics.pdf

 

[bvanant]

Our rule of thumb for implantable devices is that a good seal needs something like 7% compression.
Bill