O-rings, where do you get them? 2.5x49mm

WobblyHand

WobblyHand

H-M Supporter - Diamond Member
H-M Lifetime Diamond Member
Joined
Dec 18, 2019
Messages
6,586
So far, I've only found one place, theoringstore that carries 2.5mm(CS) x 49mm(ID) orings. They are only 20.1 cents each, but have a min order of $5 and a flat rate $10 shipping. So about $15 for 25 of them. McMaster has them $20.60 for 10 shipped. I'm trying to fix a back flow valve that is leaking. There's two o-rings, a size 123 which I have a bag of, and the 2.5x49, which I haven't sourced yet. Grainger might have them, but I need to travel a bit to get there. Do you need to be an industrial customer with Grainger? I thought that was true at one time.

Cheap o-ring kits don't go this large.

Of course I only need a couple, 10 would be a lifetime supply, I'd guess. Are there any other sources that might be less expensive? Yeah, being cheap I guess, but wondering if there might be a better source.

Searching online at hardware stores is utter futility - the websites seem to have anti-search algorithms installed. I have never seen more irrelevant results. Tell me, what does a metal number that you screw on your house have to do with a metric rubber o-ring? Struggling to see the relevance, yet that was the first result! Might call a HW store, maybe they can tell me if they carry metric o-rings and their max size they stock. Don't mind going and picking through the boxes if there's a chance of success...
 
Last edited:
That O ring looks like a strange mix of imperial and metric dimensions. That may limit your choices.
 
homebrewed said:
But I did find this.
Click to expand...
I've bought from them before apparently. (Don't remember what though!). Long time to wait for an o-ring though, as late as mid June delivery. I'd like to get my sprinkler system online before that.

That shop does CS and OD, not CS and ID, so under his system it would be 2.5x54. Confusing standards! Guess I need to go with the oring store...
 
The back flow valve has a very slow leak at the moment - I'm betting it is this o-ring. It seems the o-ring that is in there is the wrong size. (2.5x50?) I have to sort of persuade the current o-ring into place. I measured the ID and OD of the valve itself, so I'm pretty sure of the size. The lip OD which is pretty easy to measure with calipers is 54mm. The lip is 2.5mm. I probably ought to lube the o-ring with silicone grease to help it out.

It's kind of an art pressurizing these valves. Do it wrong and they sort of chatter. That means lots of water all over the place. If you slowly feed the water to the irrigation system, it works fine. Too bad I seem to forget this (every season)! Yeah, I got wet. Good thing is the valve piece I machined more than a year ago is in great shape.
 
WobblyHand said:
The back flow valve has a very slow leak at the moment - I'm betting it is this o-ring. It seems the o-ring that is in there is the wrong size. (2.5x50?) I have to sort of persuade the current o-ring into place. I measured the ID and OD of the valve itself, so I'm pretty sure of the size. The lip OD which is pretty easy to measure with calipers is 54mm. The lip is 2.5mm. I probably ought to lube the o-ring with silicone grease to help it out.

It's kind of an art pressurizing these valves. Do it wrong and they sort of chatter. That means lots of water all over the place. If you slowly feed the water to the irrigation system, it works fine. Too bad I seem to forget this (every season)! Yeah, I got wet. Good thing is the valve piece I machined more than a year ago is in great shape.
Click to expand...
Often, when looking for an O-ring I measure the groove and go to the groove charts to determine the size I need.
 
You must log in or register to reply here.
Back
Top