heatsink footprint for pcb using eagle

[amateur_25]

I'm looking for some advice on how to create my own footprint for this aluminium heatsink I stripped out of a psu. How can I ensure the footprint allows perfect alignment of the regulator with the mounting holes on the heatsink? It has 150A4Y number which doesn't seem to return any results on google.

[mariush]

It's probably a custom heatsink, made for that specific power supply manufacturer.

I'd say get a caliper and start measuring the distances between the holes, the diameter of the holes, where those support pin are relative to the corners... 

As a tip, you can also use some warm wax (from candles) to make a small rectangle in which you can press the heatsink just as if the wax was the PCB. Afterwards, you can use the impressions in the wax to determine the distances.