Big HeatSink with M2 Extender. Assembly Help

Can someone help me decipher this specification? I’m not very mechanically inclined. :frowning: I believe that M2.5 is the diameter of the threaded part. What is the “18+10”? Many thanks.

In this sketch,
M2.5 corresponds to D (not to SW, this was a careless mistake.)
18 corresponds to L
10 corresponds to B
All data in mm and without guarantee.


Ah, perfect… thanks a lot!

Perhaps this picture of the original M.2 extender board is obsolete and misleading, now?

the original M.2 extender board and the new M.2 extender board using two different FPC cables. The two types of cables should not be used intersect

Yes, I was the first to learn that the hard way and informed everyone here about the pinouts being reversed on ver 1.4. That’s why I don’t want others to make the same mistake.
My point is that the photo shows the connections for the original M.2 extender board ver 1.2, instead of the current ver 1.4. Since customers will be receiving the new board, perhaps they would be confused by the illustration of the original board, instead of what they receive?

With regards to the shorter FPC cable being used, it is still needed if the customer wants to protect the Rock Pi 4B inside a case, where the longer FPC cable would completely block access to the microSD. The only solution is to mount the SSD on to the heatsink, while using the short FPC cable because it allows the case to still be close enough to the microSD slot to be within reach. Of course, the short FPC cable needs to have the end contacts on the opposite side, just like the new long FPC cable.

Voi la, problems solved. :sunglasses:

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Hi Norbert,
The longer FPC cables are 60mm long. If you purchased the new ver 1.4 board (the shorter one with the M.2 connector on the opposite side from the SSD, then the FPC cables should have end contacts exposed on opposite sides.
Either way, the important part is to ensure that the exposed contacts face the circuit board (M.2 shim board and M.2 extender board) at both ends.
Hope this helps, my friend. :sunglasses:

Important tip: Start your tap from the threaded side of the heatsink and continue tapping the existing threads through to the opposite side of the heatsink. Otherwise, the new threads may not line up with the existing threads. :wink:

I loosened the chuck on my drill press and used it as a tap handle (while it was guided by the spindle) to avoid cross threading and breaking the tiny taps. 1/2 turn in, then 1/4 turn out to clear the cutting edge.

Amazon provided a tapered tap and a plug tap, which should be used in that order.

You probably already know these things, but I thought it would be helpful for everyone. Take your time and good luck. :sunglasses: