rubber o ring

[pete23]

im trying to find a o ring, but struggling.

so hoping someone on here may be able to help.

im after a 6mm section x 21mm inside dia x 27mm outside dia ring.

anyone have a thoughts??

it could be 7 x 21 x 28.

 

[tigler]

Where have you tried ?

 

[pete23]

Where have you tried ?

mainly flea bay at the moment, but have a local comp to phone up tomorrow.

 

[pedrobedro]

If it was 21x28 it would be a 3.5mm section wouldn't it ?

 

[gordon stephenson]

Your figures don't add up. The outside should = the inside + 2X the section.

 

[pete23]

whos figures??

mine, could be as ive no idea how to measure a o ring in o ring tech terms.

i used a set of vernier thing,ys.

 

[GeorgiePorgie]

Go into an Aldi tomorrow,they have a box of different rings,some are O rings.
Last sunday
http://www.aldi.co.uk/uk/html/offers/Offers_Week35Sunday12.htm

 

[hotrodder]

http://www.bearingboys.co.uk/21x3mm_Viton_Orings__Pack_10_-44122-p, OD of those will be 27mm

 

[tigler]

Yeah, as a 21 id x 27 od it's a 3 mm section. The Aldi kit has a 21.5 id x 3 mm section.
If it needs to be precisely a 21 x 3mm section your best bet is a bearing and seal supplier.

 

[pete23]

cheers hotrodder, but i want 6mm section

 

[GeorgiePorgie]

Erm 21+3 is 24 hotrodder I make it 24 OD

 

[GeorgiePorgie]

http://www.applerubber.com/products/o-rings.cfm?gclid=CP_gsOK4kLICFYTMtAodc20ACw

 

[hotrodder]

cheers hotrodder, but i want 6mm section

If you want a 6mm section then one or both of your other dimensions are miles out.

Erm 21+3 is 24 hotrodder I make it 24 OD

21 + 3 is indeed 24. O-rings are circular. Think about it

I can't explain it any better than everyone already has or the drawing in the bearing boys link. Oh, all right then ...

 

[MattF]

Erm 21+3 is 24 hotrodder I make it 24 OD

There's 3mm either side of the hole to account for. I.D+3+3 is the external diameter, not I.D+3. That would give you a seal with a cross section of 1.5mm.

 

[MattF]

cheers hotrodder, but i want 6mm section

What's the application? If it's nowt critical, you could just use any 6mm round, (possibly even square), section strip cut to length and glue the ends together.

 

[hareng]

im after a 6mm section x 21mm inside dia x 27mm outside dia ring.
it could be 7 x 21 x 28.

First of all you need to know the size of the O ring or the bores which its to fit in to.

Just one 3mm cross section alone has 4 o rings around that size.
then add in 3.5mm cross section dubiously two to choose from, got 5 BS211 doing nowt.

**If you can measure the the diameter that the o ring fits in to with width and also the outside diameter its to fit in to we may get some where.

Although O rings are supposed to conform to BS, buy three o rings from three places and all measure differently.
Best bet is individual cash sale at local hydraulics supplier as most theres a minimum order value £15 plus postage and individual line value of £5. So might end up with 75 o rings and find they are wrong.

 

[pete23]

cheers chaps.

you learn something every day, mine is "how to work a o ring size out"

will have a proper measure tomorrow.