O-Rings

[daedalusminos]

So maybe a thicker o ring is required.

But your groove is only 1.4mm wide, are you sure this wasn't originally fitted with a lip seal or similar?

 

[8ob]

I think this could be the problem. A 1.5mm cross section o ring in a 1.55mm groove! So maybe a thicker o ring is required.

Sounds like you need a 1/16" oring.

Bob

 

[AndersK]

You need a cross section of 1,78 or 1,8 mm. Gives 15-16% compression

Edit, forget this didn't see the width. O-ring is probably not what they originally used

 

[Milkybars]

what about an imperial one 1.588 mm is 1/16 ??

 

[awemawson]

My understanding is that an O ring groove should be marginally WIDER than the O ring cord, and the seal is formed by the pressure side deforming the cord into the ninety degree angle formed by the top of the groove and whatever it is sealing against.

The sealing is more subtle than just cramming rubber into the groove.

There is a good guide here:

O-ring installation dimension

Groove Design for correct O-ring dimensions: calculation for piston seals, rod seals and flange seal.

www.cog.de

 

[tom2207]

If there is a hydraulic fittings supplier near to hand they can usually reach you things off the shelf .

 

[mike os]

Bs806
bs014

would be my guess

silicone as first choice then viton

 

[bricol]

Always found James Walker to be a very useful guide:

https://www.jameswalker.biz/en/pdf_docs/3-o-ring-guide-issue-7

 

[Ross365]

Isn't it the case that quite a lot of O rings (by no means all) are specific sizes to the manufacturer / application? It discourages "un-authorised tampering" .

 

[mike os]

Isn't it the case that quite a lot of O rings (by no means all) are specific sizes to the manufacturer / application? It discourages "un-authorised tampering" .

most are standard,

 

[Brad93]

@matt1978 did you ever have any joy with the parts list for my torch?

 

[bricol]

Isn't it the case that quite a lot of O rings (by no means all) are specific sizes to the manufacturer / application? It discourages "un-authorised tampering" .

Unlikely I would have thought - so many standard ones available, there'll be something out there close enough to work, so not worth the bother.

Having said that . . . . . . we have some large diameter ones made with a smaller section than you would expect - we often use them to close gaps on rotating manifolds where don't want a true seal, or to have components rubbing too close - the o-ring either takes a set, or wears enough to not wear the components running past it.