Originally posted by: Aeros
how do you check if it is flat? i have one with me.... cant play with it til i get home
Another method thats a little more involed, but more difinitive then the razor trick, is to place a small droplet of water on the IHS and place a pane of glass/mirror onto it. If the IHS sticks then the surface is flat. If there is no cohesion then you should lap.
Hope that helps.