clamping force? springs shipped with various wbs?

bobkoure · 05-13-2004, 09:52 AM

Hey Folks,
I'm looking for info on recommended clamping force between CPU and heatsink (I'm an AMD guy, but Intel's interesting, too).
As well, any info on the springs and screws shipped with various 4-hole-mount water blocks (spring length, rate and screw thread-pitch is what I'm looking for).
I'd like to try my hand at writing up a "guide" - maybe, if good enough, of course, it might be welcome, well... here.
FWIW, all the time I was growing up, my Dad was in the fasteners and springs business. I seem to have absorbed at least some of that info. I've always thought that this stuff was dead easy, but given the number of questions about "how many turns?" on the forums I sometimes frequent, it's apparently not.
So far, the only "hard" info I've run across is AMD Thermal, Mechanical,and Chassis Cooling Design Guide (the major piece of info from which is Clip force as high as 30 lb is acceptable if using a 6-tab clip). I'm pretty sure that means 30lbs total. Anyone know? Bill A?
I'm also making the assumption that you'd want a heat sink clamped to a CPU just as hard as the CPU manufacturer recommended (if not harder). But this is just from the intuitive thought that things clamped together tighter exchange heat better. The relationship is probably asymptotic, but I'm guessing that the recommended clamping force leaves us well below the asymptote.
So - if you've got URLs to white papers or other stuff, please pass 'em my way.
Thanks!
Bob
PS: I'm going to be away from my PC for almost a week starting next Monday afternoon. If you reply to this thread during this period, I am not ignoring you...

bigben2k · 05-13-2004, 02:07 PM

24 lbs. 30 lbs is indeed for a socket mount. It's all in the same document (I know, it's hard to dig it up).

bobkoure · 05-13-2004, 08:53 PM

So, there's less clamping force if it's not a socket mount?
I was reading that page to be "24 lbs if you're using two lugs, 30 lbs if you're using all six". So I'd expect to see 6lbs force on each corner in a four hole mount?

bigben2k · 05-14-2004, 08:20 AM

Yep, that's correct.

05-13-2004, 09:52 AM	#1
bobkoure Cooling Savant Join Date: Feb 2003 Location: USA - Boston area Posts: 798	clamping force? springs shipped with various wbs? Hey Folks, I'm looking for info on recommended clamping force between CPU and heatsink (I'm an AMD guy, but Intel's interesting, too). As well, any info on the springs and screws shipped with various 4-hole-mount water blocks (spring length, rate and screw thread-pitch is what I'm looking for). I'd like to try my hand at writing up a "guide" - maybe, if good enough, of course, it might be welcome, well... here. FWIW, all the time I was growing up, my Dad was in the fasteners and springs business. I seem to have absorbed at least some of that info. I've always thought that this stuff was dead easy, but given the number of questions about "how many turns?" on the forums I sometimes frequent, it's apparently not. So far, the only "hard" info I've run across is AMD Thermal, Mechanical,and Chassis Cooling Design Guide (the major piece of info from which is Clip force as high as 30 lb is acceptable if using a 6-tab clip). I'm pretty sure that means 30lbs total. Anyone know? Bill A? I'm also making the assumption that you'd want a heat sink clamped to a CPU just as hard as the CPU manufacturer recommended (if not harder). But this is just from the intuitive thought that things clamped together tighter exchange heat better. The relationship is probably asymptotic, but I'm guessing that the recommended clamping force leaves us well below the asymptote. So - if you've got URLs to white papers or other stuff, please pass 'em my way. Thanks! Bob PS: I'm going to be away from my PC for almost a week starting next Monday afternoon. If you reply to this thread during this period, I am not ignoring you...

05-13-2004, 02:07 PM	#2
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	24 lbs. 30 lbs is indeed for a socket mount. It's all in the same document (I know, it's hard to dig it up). __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

05-14-2004, 08:20 AM	#4
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Yep, that's correct. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

05-13-2004, 08:53 PM	#3
bobkoure Cooling Savant Join Date: Feb 2003 Location: USA - Boston area Posts: 798	So, there's less clamping force if it's not a socket mount? I was reading that page to be "24 lbs if you're using two lugs, 30 lbs if you're using all six". So I'd expect to see 6lbs force on each corner in a four hole mount?

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