I'm making a water cooling system for my friend's computer with i7 processor. The cooling block is basically 3 parts, a copper plate that's fixed to the processor, an 'injection plate' which guides the water through the copper plate and a plate on top to attach the pipes.

Here's the injection plate, just done with my CNC router ... not the milling machine!

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Took quite a while to make that - mainly due to needing 7 different tools (milling cutters from 2mm to 10mm and drills) and machining on both sides. The actual cutting time wasn't too bad.

It will be anodised next, and the copper part nickel plated.