Just skimmed the last few pages (sadly I dont got much screen time the last few weeks) and noticed pics that looked like they are clamping down the PCB and hitting the IHS?
This is not a good idea! the force of the hit is transfered almost equally to the PCB and IHS (no matter witch one you clamp down) but the PCB can bend, and IHS can not! (at least not as much) and therefore you will bring more stress to the PCB when trying to knock the IHS off the PCB rather than the other way around.
Also you have almost dubble the surface (not mentioning 10 times the structural integrity ) by clamping the IHS vs PCB.
Be careful out there! Rather not read about more broken chips ^^