The ideal block mounting kit.
 

After a lot of experience mounting blocks over the last couple years, and tired of the tedious labor that can be repetitive block tests, have found what I consider the ideal mounting kit. The result is a cheap, quick and reliable group.


http://img46.exs.cx/img46/5913/Pernos1.jpg



The parts: (McMaster pn - Description)

-91772A161 - 18-8 SS Pan Head Phillips Machine Screw 6-32 Thread, 2-1/2" Length
This is the same thread used on the standard AMD64 back plate, so is very future proof.

-9657K154 - Steel Compression Spring Znc-Pltd Spring-Tempered, 1" L, 5/16" OD,.035" Wire
Deliver 5 lbs at full compression, for a total of 20, right on AMD recommended force.

-92741A110 - Brass Round Knurled Thumb Nut 6-32 Screw Size, 3/8" Head Dia, 1/4" O'all Height
Cheap and easy to screw without tools.

-90130A007 - EPDM Rubber Cushioning and Sealing Washer #6 Screw Size, .120" ID, 1/4" OD, .062" Thickness
This is a key element. It protects the mainboard and avoids screw rotation while tightening.

-9452K318 - Buna-N O-Ring As568A Dash Number 104
Used to hold bolt on position while mounting.

-90061A007 - Black Nylon 6/6 Shoulder Washer Short Barrel, #6 Screw Size, .040" Length
One on each side of the spring. Protect the block, keep the spring centered, and provide a smooth sliding surface to the nut.

Total cost depends on quantity, but is like U$1 per bolt assembly.


Some details of the installation:

http://img47.exs.cx/img47/3172/Pernos3.jpg

The rubber washer does a very good job, once the bolt head and mainboard are touching it, there's no rotation while tightening, so only one hand is required and no tools.

http://img42.exs.cx/img42/7019/Pernos4.jpg

The O-ring fits tightly, and holds the screw in place. Once it is close to the mobo there’s no more access needed to the backside, the rest of the installation can be done with the board mounted.


http://img42.exs.cx/img42/7501/Pernos5.jpg

Since only one hand is enough to tighten each screw, the process can be done in parallel, tightening at the same time each diagonal pair. This results in an always balanced force on the center of core, making it very safe to bare dies cpus.

I Hope this info is useful for procoolers, finding the ideal matching parts required several hours of research on Mac Master catalog.

Any suggestions to improve it will be appreciated.

Have you considered getting 15LB springs instead and only tightening them part way so it works for AMD Athlon, A64, and P4? (P4 can go up to 100, but whatever)

Looks really good. I would suggest using nylon washers instead of O-rings, its possible that they can get pushed around the bolt heads? Im not 100% sure but I used rubber washers and thats kinda what happened, this is years ago.

but that definately loooks good.

If your to do it again, I would get some 6-10lb springs or even bigger if you want, you can adjust the pressure a litttle better, I usually run about 28-30lbs on my core, just do it really carefully.

Jon

The rubber washers that holds the load is not an o-ring, it has flat faces. In the pic is already under the full spring compression and dont walk outside. nylon wont be usefull, it will require holding the screw with some tool while tightening, loosing a lot of the convenience of this setup.

I had plans of using stronger springs, but selection was limited to ones available on that catalog to keeep the same provider for all parts. Harder springs available were too wide or too long to be practical.

I'm holding back from high mounting forces, 20 lbs is more than enough. I can't measure an improvement with more force, and it can have nasty side effects: I have a permanently deformed mobo and CPU! Yes, the pcb on a 1700+ that I used a long time under big pressure, is now concave!