I had snatched a 40x40mm aluminum heatsink from an old ATI graphics card and decided to employ its use. It had two snap-fit pins that I popped off, this is designed to loosely fit through those holes. The heatsink still relies on some type of thermal paste to maintain a some-what stable connection, the mount prevents it from sliding down due to vibrations. I'm using Arctic Silver Ceramique and it has significantly reduced running temperatures of the stepper motor. It has held up to around twenty hours of printing thus far with no significant slippage.