Design of O-ring grooves

nleahcim · 05-24-2003, 01:44 PM

Hi - I'm working on designing my northbridge block - and i've run into a bit of a,w ell, stumbling block. How should I make the grooves for the o-ring? I'm using a two part design - a top and a bottom. So should I just cut a sort of half pipe design into each with the same diameters (cross sectional and actual) or I have seen some blocks that didn't seem to even have grooves on the upper piece. Or should I make the groove a little smaller in cross sectional diameter to put a little more tension on the o-ring? Thanks for your advice!

Balinju · 05-24-2003, 01:50 PM

ok here you will find the standards of the o ring groove.

now you will need to mill this channel in only one part of your block, either on the top or on the bottom only, but not on both

nOv1c3 · 05-24-2003, 02:46 PM

You could go with just a plain old gasket

Be so much easier than trying to mill a O ring grove

nleahcim · 05-24-2003, 04:09 PM

Oh, I'm not worried about the milling part - my friend will take care of that for me with his CNC milling machine. So, the groove should be square, not round? That is insane!

hara · 05-24-2003, 07:15 PM

It's not. The pressure required to deform the O ring to a rectangular cross section will ultimately seal the block tight.

Balinju · 05-24-2003, 08:20 PM

it is not insane, it will seal perfectly, but you could also opt for a rounded groove done with a ball nose if you do not like the square groove. but always follow the standards.

jaydee · 05-24-2003, 08:48 PM

This is what I went off of for designing the O-ring groove for my REV. 5.0. http://www.quadion.com/factbook/4-10.htm

MadDogMe · 05-26-2003, 04:48 AM

Quote:

you could also opt for a rounded groove done with a ball nose if you do not like the 'square' groove.

I'm not sure if that would work. Basicly you need a flat area top and bottom for the O~ring to 'flatten out' into. I think the standard/formula would be different for a rounded channel :shrug: . I'd be easier to get a good clean smooth finish on the 'square' channel...

nleahcim · 05-26-2003, 03:07 PM

I think I'll just stick with the squar groove design. Less hassle anyways.

jaydee · 05-26-2003, 03:30 PM

Quote:

Originally posted by nleahcim
I think I'll just stick with the squar groove design. Less hassle anyways.

Rounded groove is just as easy to mill. Just need a ball ended endmill. They actually make just as nice a groove as a flat ended endmill. But it is really irrelevant. As long as the groove has the proper depth it is good no matter which way you go.

MadDogMe · 05-27-2003, 06:35 AM

What about width for distortion?, O~rings 'oval' out under pressure don't they?, and they're not supposed to touch the walls?(as far as in it interferes with the O~rings 'distorting' freely?)...

I'm sure it would work with a bit of trial and error to get the dimensions right, but then again I've never seen it used comercialy with any O~ring application I've seen...

jaydee · 05-27-2003, 09:59 AM

Quote:

Originally posted by MadDogMe
What about width for distortion?, O~rings 'oval' out under pressure don't they?, and they're not supposed to touch the walls?(as far as in it interferes with the O~rings 'distorting' freely?)...

I'm sure it would work with a bit of trial and error to get the dimensions right, but then again I've never seen it used comercialy with any O~ring application I've seen...

Just has to be wide enough for the O ring to fit in, you will probably want to go deeper because there will not be as much room for the O-ring to squish. And it can certainly hit the sides of the channels. All the cars I have worked on that used O rings for the water pumps and thermostats all hade the O ring squish against the sides of both walls. Remember this is a PC not anything high pressure. You don't have to be perfect with it.

05-24-2003, 01:44 PM	#1
nleahcim Cooling Neophyte Join Date: May 2003 Location: Oregon Posts: 29	Design of O-ring grooves Hi - I'm working on designing my northbridge block - and i've run into a bit of a,w ell, stumbling block. How should I make the grooves for the o-ring? I'm using a two part design - a top and a bottom. So should I just cut a sort of half pipe design into each with the same diameters (cross sectional and actual) or I have seen some blocks that didn't seem to even have grooves on the upper piece. Or should I make the groove a little smaller in cross sectional diameter to put a little more tension on the o-ring? Thanks for your advice!

05-24-2003, 07:15 PM	#5
hara Cooling Savant Join Date: Oct 2002 Location: Malta, Mediterranean Posts: 662	It's not. The pressure required to deform the O ring to a rectangular cross section will ultimately seal the block tight. __________________ - Every great HD crash day is the day before back-up day. - My Past System - "Better to reign in Hell than serve in Heaven." - Milton, Paradise Lost. - FMZ

05-24-2003, 08:20 PM	#6
Balinju Cooling Savant Join Date: Dec 2002 Location: Malta Posts: 495	it is not insane, it will seal perfectly, but you could also opt for a rounded groove done with a ball nose if you do not like the square groove. but always follow the standards. __________________ So the bullet proof vest aint a $hit when d laser is pointed to your head Kid

05-24-2003, 02:46 PM	#3
nOv1c3 Crazy Stupid Join Date: Nov 2002 Location: Dallas texas Posts: 149	You could go with just a plain old gasket Be so much easier than trying to mill a O ring grove

05-24-2003, 04:09 PM	#4
nleahcim Cooling Neophyte Join Date: May 2003 Location: Oregon Posts: 29	Oh, I'm not worried about the milling part - my friend will take care of that for me with his CNC milling machine. So, the groove should be square, not round? That is insane!

05-24-2003, 08:48 PM	#7
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	This is what I went off of for designing the O-ring groove for my REV. 5.0. http://www.quadion.com/factbook/4-10.htm

05-26-2003, 03:07 PM	#9
nleahcim Cooling Neophyte Join Date: May 2003 Location: Oregon Posts: 29	I think I'll just stick with the squar groove design. Less hassle anyways.

05-27-2003, 06:35 AM	#11
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	What about width for distortion?, O~rings 'oval' out under pressure don't they?, and they're not supposed to touch the walls?(as far as in it interferes with the O~rings 'distorting' freely?)... I'm sure it would work with a bit of trial and error to get the dimensions right, but then again I've never seen it used comercialy with any O~ring application I've seen...

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