Mobo reinforcement - vendors take note (Bruce?)

[Since87]

I was reading a thread about motherboards flexing when the block was mounted, and got to thinking that there are likely enough people wanting to really put the screws to their CPU to justify a new product.

I'd happily pay $10 or even $15 for a well designed P4 mobo reinforcement plate.

So what are people's thoughts on the design of such a device?
I'm no mechanical engineer, but here are some design points off the top of my head.

It needs to be thin but stiff. (Steel?) Ideal if it could actually fit between the motherboard and mounting plate, so that a big hole in the mounting plate is not required for use.

The side that is against the mobo needs to be electrically insulative and durable. (Glass filled Acetal?)

The only point of contact between the device and the motherboard (other than at the screws) should be at the CPU pins because:

1. That is where the force that needs to be counteracted is applied.

2. There might be components on the back of the motherboard in other areas.

The screw holes should probably be tapped with a #6-32 thread (for US customers) so that additional hardware is not needed.

Edit: For clarity and to add an issue.

[BillA]

look at the Thermalright plates

[Since87]

Any idea if it is available separate from the heatsink?

A quick google didn't find anything suggesting so.

[BillA]

don't think so
but if there is a demand they will supply it

note that the AMD ref design for the 64 has such
(but we have seen a mobo without it !!)
at 60+ lbf it had better be there

[pHaestus]

I doubt it. The thermalright plate IS nicely designed though.

Too bad Intel started with the new TIM on IHS's. Without that foolishness I would have suggested just popping the top and using ~ 20-24lbs like Athlons...

[BillA]

if all 3 lugs are engaged the max is 30 lbf
(no idea why JoeC is using 15 lbf ???

[Les]

Originally posted by unregistered
if
(no idea why JoeC is using 15 lbf ???

About 50% of the stress you apply?
"~10kgf (22lbf) applied across the TIM joint (90% of the AMD maximum)" from here
Which is equivalent to 30.8lbf on JoeC's 140sq mm die

[Groth]

Hmmm, I made something also those lines way back when.

I used a 2" by 3" by 1 mm thick piece of powdercoated steel (recycled bottom of a defunct arcade stick), drilled holes to match my socket-A platform, brazed in 3" 6-32 machine screws, and used a couple of squares of old mouse pad to support the back of the socket without crushing anything.

It's been behind one mobo or another for a year and a half. Makes changing blocks real easy.

Anyone can make one. Just substitute epoxy for the the braze, and polyurethane for the powdercoat.

[Cathar]

Originally posted by unregistered
if all 3 lugs are engaged the max is 30 lbf
(no idea why JoeC is using 15 lbf ???

Yes, I also thought that 15lbf seemed rather low.

I've often considered a 1/8" steel plate with some 1/16" rubber gasket material glued onto it as a means of insulating the back of the motherboard for TEC use. I use such an arrangement on my video cards with sunken holes in the metal plate to fit pan-head bolt heads in. Of course the bolts need to be fixed for a motherboard where you can't get behind to hold the screws while tightening the springs down, but that could be achieved through any number of glue methods. The spacing is a little tight but it's doable. Wouldn't stop all of the flex, but would stop most at the mounting pressures considered. Easy enough to do with a drill press and some materials for less than $5.

[Tweekster]

Just use the motherboard tray to take the load off of the MB.......set your motherboard into the case, mark the heatsink hole locations, remove MB and drill the holes.........fab 4 spacers from nylon stock (Lowe's, Home Depot, etc) the same length as the standoffs and superglue to the MB tray......then get long enough screws to bolt through the water block, MB, spacers and MB tray.

Or for a really clean setup, drill the 4 holes small enough, then pick up a tap (10-32 typical, I think) at your local hardware store and tap them, then install 4 standoffs......get long enough screws to bolt through the WB, MB and standoffs.

I've used both of these methods.

The downfall of a reinforcement plate is that it still just spreads the load into the motherboard.

[hydrogen18]

my soyo p4x400 had this on it stock. I just upgraded to a ic7-g and never looked to see if it had something on the back.

[Groth]

Originally posted by Tweekster
The downfall of a reinforcement plate is that it still just spreads the load into the motherboard.

A reinforcing plate (ideally) applies an force to the back of the socket equal and opposite to the waterblock mounting force, eliminating the board flexing that normally generates that counter balancing force.

Your set up does nothing to reduce board flex.

[Tweekster]

Originally Posted by Groth

A reinforcing plate (ideally) applies an force to the back of the socket equal and opposite to the waterblock mounting force, eliminating the board flexing that normally generates that counter balancing force.

Your set up does nothing to reduce board flex.

Groth,

Your missing the point. The motherboard doesn't flex as much from mounting pressure as it does from eccentric loads from the weight of the WB or the weights and bends of the plumbing creating an offset load.

Example.....in a typical tower the WB is approx. 3/4" off the face of the MB. Combine this with the bends of the plumbing and the weight of water in the plumbing you have a fairly high twisting force (called moment in the engineering world) that is ripping the WB off the MB. It also creates an imbalance of pressure on the proc core, especially athlons.

By thru bolting the entire assembly to the motherboard tray you've combined the stiffness of the motherboard with the stiffness of the MB to help resist the twisting force (moment), therefore taking stress from the MB.

Do the engineering, it does alot more than 'nothing'.

[Groth]

Originally Posted by Tweekster

The motherboard doesn't flex as much from mounting pressure as it does from eccentric loads from the weight of the WB or the weights and bends of the plumbing creating an offset load.

Yah, right. Show me your numbers. I'll put my 50 kgf applied to the board a few cm from the socket versus your couple pounds of block/hose/water with a 3/4" lever arm.