Rolock 90 o-rings - another post

[Apteryx54]

Hi, have had the Rolock 90 system for several months (~20 dives) with no issues and appreciate the bayonet and twist locking. Thought I should add some spare o-rings to the save-a-dive kit as although I lightly lube the mating o-ring, our dive sites are often silty sandy with some abrasion. Through the forum and discussion on Rolock 90 o-rings and looking at the Rolock website, ( O-rings for bayonet lock (from 2006) – Rolock ) I sourced and purchased the O-Ring: Buna-N, Round, 2.5 mm C.S., 96 mm I.D.
My query is that the o-rings at 96mm I.D. appear to be smaller than the groove on the drysuit side ring which measures ~104mm with vernier (see pics)
First photo shows a new o-ring inside the one I removed with two more new o-rings. (is the old one stretched?)
2nd photo of vernier measuring the drysuit ring ID on the o-ring groove.

The new 96mm o-rings do fit the ~104mm groove with a gentle stretching. Is this normal?

 

[-JD-]

@Zef maybe?

 

[lexvil]

I don’t know the answer, I have ordered some to see how it works, in 3 years of use so far I haven needed to replace the o ring’s and they are still fine.

 

[lexvil]

These appear to be the correct replacement, I have received 10 from Mc Master and changed one , it a good fir but takes a bit to work them into the deep groove, any bigger and they wouldn’t work as they need to be massaged into the groove.

 

[rjack321]

These appear to be the correct replacement, I have received 10 from Mc Master and changed one , it a good fir but takes a bit to work them into the deep groove, any bigger and they wouldn’t work as they need to be massaged into the groove.

what was the mcmaster part number if you have that handy?

 

[Apteryx54]

Thanks @lexvil . All good

These appear to be the correct replacement, I have received 10 from Mc Master and changed one , it a good fir but takes a bit to work them into the deep groove, any bigger and they wouldn’t work as they need to be massaged into the groove.

 

[lexvil]

what was the mcmaster part number if you have that handy?

 

[mr_v]

@Apteryx54 , This is a cross-post from the other thread and my findings. You need a ring with 103 - 105mm inner diameter and 2.5-2.62mm cross section.

Rolock changed their systems. You and I have Rolock 90 with white arrows instead of dimples for indicators. The specs on the site referencing 96mm inner diameter won't work.

2.5mm x 105 mm o-rings will give you easier option for donning on and off. However, you may also unlock your glove by accident.

2.62mm o-rings are hard to find. I have some on the way, 103 inner diameter. These should be tighter and less prone to accidental unlocking.

 

[Apteryx54]

@mr_v Many thanks for the post clarifying what I need! I will try and source the 2.62mm x 103mm id here in Australia. Appreciate your vendor name and any part number.

By the way, another twist (pun intended) for my Rolock 90s. They arrived 'dimpled' but unpainted and I added a couple of dots from a white paint-stick. No arrows.

 

[mr_v]

I have these o-rings coming in soon:

Metric Buna O-rings 101.27 x 2.62mm Minimum 5 pcs

22.3 mm ID x 27.1 mm OD x 2.4 mm CS-Price for 25 pcs

oringsandmore.com

I ordered 2.5mm x 105mm from McMaster Carr:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Note, o-rings can handle 3% stretch with reasonable cross-section loss, so 101mm is okay for 2.62mm cross-section.