O-ring groove and other questions
 

Right, various questions, but first, a slight background.

I'm having a waterblock built, proffesional machinists will be making the entire copper plate sections that comprise the block, basically because I have neither the machines or the skills required to make circular grooves 1mm wide and 6mm deep.

Therefore, a very elite precision engineering centre will do it for me :)

I will also ask them to mill a groove for an o-ring, and need to know how deep and how wide this should be.

I also need to know what type ( width and length etc. ) alan bolts to use to hold this thing together. The machinist will drill and tap the holes in the plates, but I need to know what dimensions these holes should be.

Also, I intend that the top plate have holes for mounting on a Socket A, P4 and Hammer systems, like the top of the Waterchill systems from the Vapochill guys, and I need to know where the centres of each of these holes should be, and what diameter they should be as well.

Cheers in advance,

GTA

err... I would dare asking one question, but multiple ones in one thread makes it look like your lazy and want others to do all your thinking for you. However, I do have some time on my hands :D
there are already posts on o-rings. I remember one of the top of my head from BigBen2k. Do a search. To find out what screws or whatever to use, consider land space in which you have to attach, and what screw you want to use or have room for. If you provide a screw, there is no reason they cant tell you what bit to use. So the question is how deep of material are you attempting to use, and that determins what screw head to use. Circular logic, but it works. Go to a metal shop and ask to see some screws. Say.... "that one" and they will cut u a hole. There is a chart floating arond here on hole specs. It has green, red and little arrows. Ill let someone else link you to it.
Did you consider bringing your mobo to the shop and letting them figure it out? Get a ruler.

Why not just buy one? Its cheaper that way ( I am lazy too). ;)

Okay....

I'm not rich enough to afford an AMD and a P4 motherboard. I have the AMD mounting specs for socket A, I need the P4 ones.

And as for Hammer, well, if I had one of the boards for that, i'd be very happy.

Okay, asking about the screws was perhaps a little lazy, but its late here in the UK, and I'm tired, humour me :) I'm also not very clued up on tapping and bolts, i've never used them before, having always soldered my blocks together in the past.

The question should really read " I know the height of the block, but how much height, in mm will the o-ring add, and how much does it need to compress to form a watertight seal "

I was simply asking for some help. If you cannot or will not provide any, because you think i'm a noob or something, then fair enough.

Google is your friend. Has all the answers and pictures to boot about O rings.

If you cannot afford a mobo, then why are you getting a block made? Paper wieght?

if your in the UK and its late here in the states.. man you ARE a nightowl. Frankly don't worry about the screws man. Go find some machine screws that are 1 1/4 longer than your baseplate including head measurement. I don't know the specs so humor me. The head should be able to be fully screwed in and not rise above the plate it is being screwed into. So you will have 2 depths of cutting... the first that is cut to accomodate head size and the 2nd through the center to accomodate the shaft. The only tapping should be on the target plate, the head recieving plate need not have any threads. I can't tell you any measurements as I don't have any provided via.. you. Any machine shop should be able to measure standard machine thread, and measure width of screw radius. Machine shops need only see the screw to easliy make a tap for it. Make sure the screw goes in.. 3 mm as a guestimate + the 1mm-2mm gap that the o-ring will rise above block. I cant give you, that as I dont know how thick an o-ring you are using.
See? I dont think anyone can help with that stuff cept you provide the exact specs. And that is a time waster. Just bring your 1 1/4 machine screws to the shop and say "put this in".
Bring in 3-4 o-rings to the shop. Make them of varying diameters, as he could cut the ring differently.
Man.. its late.

o-rings last entry on page 6
http://forums.procooling.com/vbb/sho...G&pagenumber=6

mounting holes for amd on page 7
http://forums.procooling.com/vbb/sho...s&pagenumber=7

socket a and socket 478 hole dimentions are here :) Is this what you were refering to?

The standard for the O-ring says that :
H=0.67*D to 0.7*D and L= 1.18*D to 1.2*D

Channel MUST be wide tan O-ring because O-ring must be deformed to ensure the sealing !

I finally went to bed, was 5 o'clock when i posted that last one I think.

Cheers for the help though, just what I was looking for.

Jaydee, I've got an AMD motherboard, but I havn't got a P4 motherboard. Its not going to be a paperweight.

GTA I think you are making this harder then it needs to be.

here is what you do.

take your design to the machinst. Talk with him. Allow him to make the descisions on O ring. Most machinist have experiance with this sort of thing. Also find a good sorce for O-rings. Once the block is made, take it in and have them fit an O-ring to the block. As for the screws. Defonitly go with a machine screw with fine threads. This will allow you more turns which gives you a better fit. I dont know why, but I think I want to say I used 8-32 screws.


I hope this helps.

Good luck on the endevore.

Also seeing as you are getting a MAJOR favor from the machinist. And trust me it takes alot of time to do these things, you should float hims a good sized TIP in the end.

Fix

Cheers Fix, I'll let him make the decision on the o-ring in that case.

Although he's not doing me a favour, I'm going to be charged at about £40 an hour for his time, + materials.

But having said that, there is no way I could make this block, its just too precise, 1mm channels 6mm deep, and other parts as well.

since you're not in the US you'll want them to tap the holes to bolt the cover on with an M4 thread instead of a 8-32 since I doubt you can even find any american standard thread sizes in UK.

I would assume that it would fine to have them just tap thru the entire block since that's on the outside edges and won't effect anything and just make sure the screw you use is less than the combined thickness of your cover + block.

How about this embodiment?

Is the volume of the groove that of the O ring?

Yeah...it is almost identical...maybe it shold be a little larger, but this looks like a perfect fit...assembled, of course.

i think the groove should have been a little bit less deep according to the standards.
but it does not mean that if anybody does not follow the standards, then his block will leak :rolleyes:

I don't expect any leaks...will know for sure soon...:)

if i head well, if the cross sectional area of the groove = the cross sectional area of the o-ring, i think that that would not seal very well. Any help from others pls???

My explaination to this is that there will not be enough force on the oring to deforme because it will find its exact position (and even if the block is tightened the mostly possible, most of the force of the top will be exerted on the base itself). at least, the block which i did with hara, we followed the rules which i posted and there remained a space between the top and the base of the block, but no leak :cool:

dido.

The pressure would deform the o-ring in a slightly different manner than a square groove, but it's not too far off.

the rules still have to be applied though, IMO.

The force on the o-ring comes from it's deformation....and yes, there is definitely enough force to deform it, it is obvious since there is a "mark" on the plexi more than 1mm wide proving that the o-ring is firmly compressed.

There is one point, though....is the cross-sectional area difference between the groove and the o-ring the same in case of square-shaped groove and this type of groove?

Something tells me the squareish grove is better. There is more area of contact of the O ring with the plexi.

More area probably means LESS specific pressure...

IMO a rounded groove like you have in your block would seal better than a square groove * , but i would still follow the standards, what i mean is that if I were you, I would have made the groove a little shallower so that more force would be applied on the o ring it self.

Edit * it think like this because all off the o-ring would surely be in contact with the walls, in a square groove, one cannot be sure if the oring is in contact with even the corners of the groove :confused:

anyone is sure about this one??